Sunday, September 17, 2017

Dino Bios: Giganotosaurus.

Giganotosaurus carolinii Holotype Specimen MUCPv-CH 1 (Carmen Funes Municipal Museum):
G. (Tyrannotitan) chubutensis (MEF Museum):
G. (Mapusaurus) roseae (Nagoya City Science Museum):
Time: 115.469-84.1 million years ago, late Albian-late Santonian of the early Cretaceous period.
Place: South America.
Size: 35-50 feet Feet (10.6-15.3 meters).
Weight: 6.3-8.2+ tons.
Diet: Carnivore.
Skull: 1.498-157.8+ cm. 
Type species: G. carolinii.
My Additional Species:
1. G. (Mapusaurus) roseae.
2. G. (Tyrannotitan) chubutensis.

Let's talk about Giganotosaurus!

Description and Specimens:
Giganotosaurus was a member of the giganotosaurini family, and it was one of the largest carnivorous theropod dinosaurs of all time. In 2004, Mazzetta et al., (2004) gave Giganotosaurus carolinii a weight of 8.2 tons. In 2014, Campione et al., (2014) gave Giganotosaurus carolinii a weight of 6.3 tons. Then ]Snively et al., (2018) gave it 8.0 tons. In 2019, Persons IV et al., (2019) gave MUCPv-CH 1 6.9 tons (6,260 kg). In total, Giganotosaurus carolinii was 6.3-8.3 tons in weight. Blanco and Mazzetta (2001) said that Giganotosaurus carolinii was capable of running up to 14 meters per second, or 31 miles per hour, but Snively et al., (2018) said that it was less agile than Tyrannosaurus but more agile than other theropods (pg. 63). Dececchi et al., (2020) says that theropods over 1000 kg would not be able to run fast, despite their different limb lengths. Instead, they were speed-walkers (Dececchi et al., 2020, "Abstract;" "Discussion," "Getting up to speed" p. 3; "Why tyrannosaurids?" p. 2) (EurekAlert, 2020). They could do this for a long time (The Canadian Press, 2020). The young seem to have been faster ("Results," "Relative leg length" p. 1), and pack-hunting was also suggested to help large theropods take down prey (The Canadian Press, 2020) (Dececchi et al., 2020, "Discussion," "Why tyrannosaurids?" p. 2-3). So as for speed, Giganotosaurus (all three species) may not have been fast runners, but pack-hunting could have helped in taking down prey.

According to Kenneth Carpenter (2002), in most predatory theropods used their mouths first to grab prey first, and then they would grab their prey "in a 'bear hug'" with their hands (pg. 72, "Conclusion"). For Allosaurus, a relative of Giganotosaurus, its arms were relatively long and robust. The range of motion in its arms seems to have allowed it to grab and pull "moderately large prey" towards it. Carpenter says that evidence of Allosaurus using its arms to hunt large sauropods isn't present ("Biomechanical Analysis," pg. 71). Text-figure 9 shows Allosaurus', and other theropod's, range of motion for their hands (pg. 69). Apparently, it can bend its hand quite well outward. Perhaps this was the same for Giganotosaurus. Matt A. White et al., (2015) says that carcharodontosaurid arms were similar to tyrannosaurs, in which they used their jaws to grab their prey first and used their arms to secure it ("Discussion," p. 6). Therefore, it seems that carcharodontosaurids like Giganotosaurus used their hands to help their jaws capture prey mainly. However, their hands might have been able to bend slightly like Allosaurus'.

Carnivorous theropod dinosaurs had enamel in their teeth, so they must have had lips to cover and protect their teeth (Reisz and Larson, 2016, pg. 64-66) (Blake Eligh, 2016) (Mindy Weisberger, 2016) (Emanuela Grinberg, 2016) (Phys, 2016). Therefore, Giganotosaurus would have had lips covering its teeth. Interestingly, dinosaurs couldn't move its tongues (Mindy Weisberger, 2018) (ScienceDaily, 2018).

Carcharodontosaurus had short arms, similar to tyrannosaurinae (Guinard, 2020, Abstract).

1. MUCPv-CH 1 (Skull from Coria and Salgado, 1995, p. 225 Figure 1) (Scale bars are A: 1 meter, B and C: 10 cm):
Length: 41 feet (12.4 meters).

2. MUCPv-95 (Dentary from Calvo and Coria, 1998, pg. 120 Figure 5):
Length: 43 feet (13.1 meters).

Time Period and Species:
Giganotosaurus lived in South America. I consider there to be three species within the genus: G. (Tyrannotitan) chubutensis, G. carolinii, and G. (Mapusaurus) roseae. G. (Tyrannotitan) chubutensis 
is the oldest member of the giganotosaurini (Novas et al., 2013, pg. 15 Figure 12) (Novas et al., 2015, p. 2). It was discovered in the Cerro Castano Member (115.469-101.4 Ma) of the Cerro Barcino Formation (Krause et al., 2019, pp. 35 and 40, Figures 2 and 6) (Novas et al., 2005, p. 227). The holotype, MPEF-PV 1156, is 35 feet long (10.6 meters). The largest specimen, MPEF -PV 1157, was 42 feet long (12.9 meters). 

G. carolinii's is the second oldest species in the genus. It was named after the man R. D. Carolini, who discovered the holotype specimen (Calvo, 1999, pg. 26-27).  G. carolinii's fossils were found in the Candeleros Formation (Coria and Salgado, 1995, p. 225). U-Pb, and zircon, dating from Garrido (2010) gives two dates: 97 Ma, plus or minus 3 million years, and 94 Ma (p. 134). In total, this is 100-94 Ma. Dating from Tunik et al., (2010) give a age of 104.3 Ma, plus or minus 2.5 million years, 100.5 Ma, plus or minus 2.1 million years, and 98.6 Ma, plus or minus 2.5 million years (pp. 270-271). In total, this is 106.8-98.4 Ma. Tunik et al.'s dates have been backed up by Krause et al., (2019) (p. 42). U-Pb dating from Di Giullo et al., (2012) give 102 Ma, plus or minus 2 million years, and 100 Ma, plus or minus 8 million years. Some zircon grains give a date of 105 million years (p. 560 "Results"). In total, this gives an age range of 108-92 Ma. In total, the Candeleros Formation is 108-92 Ma. This is middle Albian-early Turonian in age. It seems that G. (Tyrannotitan) chubutensis and G. carolinii coexisted for a little while, since the Cerro Carcino, and Candeleros, Formations are mostly contemporaneous (both formations are equal in time) (Krause, 2019, p. 42; p. 35 Figure 2; p. 40 Figure 6). 

The holotype specimen of G. carolinii, MUCHv-CH 1, is 70% complete (Jorge Orlando Calvo, 1999, p. 26-27), and measures 41 feet (12.4 meters) (Coria and Salgado, 1995, give a length of 12.5 meters, while Coria and Currie, 2002 give a length of 12.0 meters). The holotype's skull was 1.498 meters long, and its femur was 132.5 cm long. A second specimen, MUCPv-95, is based on a dentary (bottom jaw fragment) that measures 59 cm, compared to MUCPv-CH 1's 56-cm dentary. Based on this, MUCPv-95 was 43 feet long (13.1 meters), 5.4% longer than MUCPv-Ch 1. Its skull would have been 1.578 meters long. This makes Giganotosaurus, in total, 41-43 feet long (12.4-13.1 meters).

The third, and latest, species is G. (Mapusaurus) roseae. G. (Mapusaurus) roseae was discovered in the Huincul Formation (Coria and Currie, 2006, "Abstract," p. 74). Up to a minimum of nine individuals were found together in the formation (Bell and Coria, 2013, "Abstract").  Corbella et al., (2004) give a radiometric age of 88 million years, plus or minus 3.9, for the formation, based on a fission-track analysis ("Abstract;" "Characteristics and radiometric age of the tuff bed," p. 229). This gives a full time frame of 91.9-84.1 Ma. The Huincul Formation is overlying (above) the Candeleros Formation (Tunik et al., 2010, pg. 262 Figure 3) (Coria and Salgado, 1995, pg. 226) (Coria and Currie, 2006, pg. 74), which means that it is younger than the Candeleros Formation. I've given an age of 108-92 Ma for the Candeleros Formation, so I'm giving the Huincul Formation an age range of 92-84.1 Ma. This is early Turonian-late Santonian in age. G. (Mapusaurus) roseae was also the largest species of Giganotosaurus, reaching 36-50 feet in length (10.9-15.3 meters). 

All three species have a chin/ventral process or flange on their dentaries (Novas et al., 2005, p. 227) (Coria and Currie, 2006, pp. 83-84). All three species have 15 teeth in its dentary, and 2 serrations per 1 mm on its teeth (Novas et al., 2015, pp. 6-7). Both G. carolinii and G. (Mapusaurus) roseae had one pneumatopore/pneumatic foramen on the medial views of their quadrates (Hendrickx et al., 2015, Figure 5 B and C). G. (Tyrannotitan) chubutensis doesn't seem to have one preserved. All three species have tall dorsal and caudal neural spines (Novas et al., 2015, pp. 13-14, and 17) (Coria and Currie, 2006, pp. 90 and 92) (Coria and Salgado, 1995, p. 225). Coria and Salgado (1995) said that G. carolinii had tall dorsal neural archs (p. 225), but Figure 2 shows what seems to be tall dorsal neural spines as well. All three species also had similarly-shaped ilia (Novas et al., 2005, p. 227 Figure 1) (Coria and Currie, 2006, p. 99 Figure 26). G. carolinii's ilium was damaged (Carrano et al., 2012, p. 235), but it's likely that its ilium was shaped like the other two species'. All three species seem to have similarly-shaped femora, and share a large 4th trochanter (Coria and Salgado, 1995, pp. 225-226) (Coria and Currie, 2006, p. 103) (Novas et al., 2015, p. 22). G. (Tyrannotitan) chubutensis' autapomorphy (distinguishing characteristic) that separates it from G. carolinii and G. (Mapusaurus) roseae is that three of its teeth had bilobate denticles on its teeth (Novas et al., 2015, p. 8). 

Taurovenator, a carcharodontosaurid that was stated to have lived alongside G. (Mapusaurus) roseae (Motta et al., 2016), is now considered a junior synonym of G. (Mapusaurus) roseae (Coria et al., 2019, Discussion para. 4) (The Theropod Database, "Mapusaurus roseae," "Comments").

Coria et al., 2019 on Taurovenator (Discussion para. 4):
G. (Mapusaurus) roseae Skull (NBC, 2006):
G. (Mapusaurus) roseae in Chased by Dinosaurs:
Note: In the series, it's called "Giganotosaurus," but it's actually G. (Mapusaurus) roseae. If you're a splitter, then this would be Mapusaurus roseae. For me, this show isn't entirely off in calling this theropod Giganotosaurus, since there's little to differentiate the two species from what I've investigated.

G. (Mapusaurus) roseae in Planet Dinosaur:
"Long Tooth" the G. (Mapusaurus) roseae in Dinosaurs: Giants of Patagonia:
Prey: 
Giganotosaurus' prey consisted mainly of sauropods. G. (Tyrannotitan) chubutensis hunted the titanosaurs Chubutisaurus and Ligabuesaurus, and the rebbachisaur Amazonasaurus. It also seems to have hunted the large titanosaur Patagotitan, along with G. carolinii.

G. carolinii hunted the rebbachisaur Limaysaurus, the titanosaurs Andesaurus, MMCH-Pv 47, Patagotitan, MUCPv-251, and MOZ Pv 1221. MUCPv-251, a sauropod that is possibly a titanosaur, and MOZ Pv 1221, a titanosaur from the Candeleros Formation, are unidentified genera. MUCPv-251 could be the same genus as MOZ Pv 1221, or both sauropods might actually be Argentinosaurus. 

Giganotosaurus carolinii vs. Andesaurus:
Patagotitan:
MOZ Pv 1221 (Otero et al., 2021, Figure 5) (MOZ Pv 1221 is brown, Andesaurus is yellow, and Limaysaurus is blue):
G. (Mapusaurus) roseae hunted the titanosaur Argentinosaurus, the rebbachisaur Cathartesaura, and the ornithopod Anabisetia.

G. (Mapusaurus) carolinii vs. Argentinosaurus (Planet Dinosaur):
Enemies:
G. (Tyrannotitan) chubutensis' enemies consisted of the ceratosaurid Genyodectes, the spinosaur Irritator (22-24 feet; 6.8-7.3 meters), the tyrannosauroid Santanaraptor, and the abelisaur Spectrovenator.

G. carolinii's enemies consisted of the abelisaur Ekrixinatosaurus (24 feet; 7.2 meters), the dromeosaur Buitreraptor (4 feet; 1.3 meters), and perhaps the spinosaurid Spinosaurus quilombensis (27-55 feet; 8.1-16.8 meters).

G. (Mapusaurus) carolinii's enemies were the abelisaurid Skorpiovenator (15 feet; 4.5 meters), the neovenatorid Gualicho (24 feet; 7.2 meters),and perhaps Spinosaurus quilombensis (27-55 feet; 8.1-16.8 meters), just like G. carolinii did. However, confrontations between G. (Mapusaurus) roseae and Spinosaurus would not have been frequent, due to both predators inhabiting different ecological niches. Spinosaurus would have preferred rivers and fish (Kristen Rogers, 2020, "Competing for food," p. 1), while G. (Mapusaurus) carolinii would have preferred land.

Skorpiovenator in Planet Dinosaur:
Links:
1. Giganotosaurus carolinii:
Coria and Salgado (1995):
https://vdocuments.mx/a-new-giant-carnivorous-dinosaur-from-the-cretaceous-of-patagonia.html

Calvo and Coria (1998):
http://www.arca.museus.ul.pt/ArcaSite/obj/gaia/MNHNL-0000776-MG-DOC-web.PDF

Link 2: 

https://www.researchgate.net/publication/40662857_New_specimen_of_Giganotosaurus_carolinii_Coria_Salgado_1995_supports_it_as_the_largest_theropod_ever_found
Jorge Orlando Calvo (1999) (PP. 17-18, 22-24, 26-27, and 41):
https://www.researchgate.net/publication/284053211_Dinosaurs_and_other_vertebrates_of_the_Lake_Ezequiel_Ramos_Mexia_Area_Neuquen-Patagonia_Argentina
Tu Casu Estu Destino. "Villa el Chocon" (Pg. 1):
http://neuquentur.gob.ar/en/destinations/villa-el-chocon/
Welcome to Argentina. "Carmen Funes Municipal Museum":
https://www.welcomeargentina.com/cutralco-huincul/carmen-funes-municipal-museum.html
Time:
International Chronostratigraphic Chart (2020):
https://stratigraphy.org/timescale/
International Commission of Stratigraphy Website:
https://stratigraphy.org/news/130
Size:
https://psdinosaurs.blogspot.com/2018/12/giganotosaurus-specimen-sizes.html
Link 2:
https://psdinosaurs.blogspot.com/2018/10/how-big-was-mucpv-95.html
Link 3:
https://psdinosaurs.blogspot.com/2018/10/calculations-for-largest-theropods.html
Weight:
Mazzetta et al., (2004) ("Abstract;" Pages 9-10, 12):
http://www.miketaylor.org.uk/tmp/papers/Mazzetta-et-al_04_SA-dino-body-size.pdf
Campione et al., (2014):
https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/2041-210X.12226
Snively et al., (2018) (Table 3):
https://peerj.com/articles/6432/
Link 2:
https://peerj.com/preprints/27021.pdf
Persons IV et al., (2019) (Table 2):
https://onlinelibrary.wiley.com/doi/epdf/10.1002/ar.24118?tracking_action=preview_click&r3_referer=wol&show_checkout=1
Abstract:
https://onlinelibrary.wiley.com/doi/pdf/10.1002/ar.24118
Hands:
Kenneth Carpenter (2002):
https://www.researchgate.net/publication/225366451_Forelimb_biomechanics_of_nonavian_theropod_dinosaurs_in_predation
Matt A. White et al., (2015) ("Discussion," p. 6):
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0137709
Lips:
Reisz and Larson (2016) (Pg. 64-66):
https://cansvp.files.wordpress.com/2013/08/csvp-2016-abstract-book-compressed.pdf
Blake Eligh (2016):
https://www.utoronto.ca/news/did-dinosaurs-have-lips-ask-university-toronto-paleontologist
Mindy Weisberger (2016):
https://www.livescience.com/54912-did-t-rex-have-lips.html
Emanuela Grinberg (2016):
https://www.cnn.com/2016/05/22/world/dinosaur-lips-teeth-study/index.html
Phys (2016):
https://phys.org/news/2016-06-dinosaurs-lips.html
Tongue:
Mindy Weisberger (2018):
https://www.scientificamerican.com/article/t-rex-couldnt-stick-out-its-tongue/
ScienceDaily (2018):
https://www.sciencedaily.com/releases/2018/06/180620150129.htm
Speed and Agility:
Blanco and Mazzetta (2001):
https://www.app.pan.pl/archive/published/app46/app46-193.pdf
Snively et al., (2018):
https://peerj.com/preprints/27021.pdf
Dececchi et al., (2020):
https://www.researchgate.net/publication/336117841_The_fast_and_the_frugal_Divergent_locomotory_strategies_drive_limb_lengthening_in_theropod_dinosaurs
EurekAlert (2020):
https://www.eurekalert.org/pub_releases/2020-05/p-trw051320.php
The Canadian Press (2020):
https://www.kamloopsthisweek.com/news/research-says-t-rex-was-built-for-long-distances-not-sprints-1.24134506
Prey:
Limaysaurus:
https://psdinosaurs.blogspot.com/2018/12/size-calculations-for-herbivorous.html
Andesaurus:
Time:
Mannion and Calvo (2010):
https://academic.oup.com/zoolinnean/article/163/1/155/2625609
Calvo and Bonaparte (1991):
https://paleoglot.org/files/Calvo&Bonaparte%201991.pdf
Size:
https://psdinosaurs.blogspot.com/2018/12/size-calculations-for-herbivorous.html
Patagotitan:
Time:
Carballido et al., (2017):
http://rspb.royalsocietypublishing.org/content/284/1860/20171219
Size:
https://psdinosaurs.blogspot.com/2018/12/size-calculations-for-herbivorous.html
MUCPv-251:
https://psdinosaurs.blogspot.com/2020/08/a-giant-sauropod-argentinosaurus-from_22.html
Size:
https://psdinosaurs.blogspot.com/2018/12/size-calculations-for-herbivorous.html
MOZ Pv 1221:
https://psdinosaurs.blogspot.com/2021/01/giant-titanosaurs-40-tons-or-more.html
Size:
https://psdinosaurs.blogspot.com/2018/12/size-calculations-for-herbivorous.html
Enemies:
Ekrixinatosaurus:
Time:
https://www.researchgate.net/publication/262222847_A_new_Abelisauridae_Dinosauria_Theropoda_from_northwest_Patagonia
Size:
https://psdinosaurs.blogspot.com/2018/10/calculations-for-largest-theropods.html
Buitreraptor:
Size:
https://psdinosaurs.blogspot.com/2018/10/calculations-for-largest-theropods.html
Time:
https://www.app.pan.pl/archive/published/app56/app20090127.pdf
Link 2:
https://www.sciencedirect.com/science/article/pii/S0195667117300678
2. G. (Tyrannotitan) chubutensis:
Skeleton:
MEF Museum. "Cast Production and Design Services for Museums" Catalog:
https://mef.org.ar/pdf/ExhibitsMEF_2019.pdf
Link 2:
https://mef.org.ar/visits/exhibitions/
Size:
https://psdinosaurs.blogspot.com/2018/10/calculations-for-largest-theropods.html
Time:
Novas et al., (2005) (Pg. 227):
https://www.researchgate.net/publication/7901883_A_large_Cretaceous_theropod_from_Patagonia_Argentina_and_the_evolution_of_carcharodontosaurids
Benson et al., (2010) (Figure 3):
https://www.researchgate.net/figure/Relationships-of-Cretaceous-allosauroids-based-on-the-phylogenetic-analysis-herein_fig3_272152523?_sg=sg8gP3l_KoTmLPM7P9r-Lu_yNk9SC72jXEy7GrKPInaa4D1wqfQQSERNvHNSCGjUX0VdyILWGIKwJYn1Oo3d5w
Full Paper:
https://www.researchgate.net/publication/26892358_A_new_clade_of_archaic_large-bodied_predatory_dinosaurs_Theropoda_Allosauroidea_that_survived_to_the_latest_Mesozoic
Eddy and Clarke, (2011) (Figure 55):
https://www.researchgate.net/figure/Phylograms-and-comparisons-of-body-size-optimization-across_fig27_50892373
Full Paper:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3061882/
Novas et al., (2013) (Pg. 11):
https://www.researchgate.net/publication/259045022_Evolution_of_the_carnivorous_dinosaurs_during_the_Cretaceous_The_evidence_from_Patagonia
Novas et al., (2015) (Pg. 2):
Khosla and Lucas (2016) (Pg. 104, Table 9):
https://books.google.com/books?id=OsJQDwAAQBAJ&pg=PA104&lpg=PA104&dq=Cerro+Castano+member&source=bl&ots=Z80R-QvpzZ&sig=ACfU3U2EnTHODxW1x5MFakQNnmYpM4Knxg&hl=en&sa=X&ved=2ahUKEwjmyOyu5rfqAhXzj3IEHbF0BEQQ6AEwDHoECAwQAQ#v=onepage&q=Cerro%20Castano%20member&f=false
Ezcurra and Novas (2016) (Pg. 146):
https://www.researchgate.net/publication/305011083_Theropod_dinosaurs_from_Argentina
Tomas et al., (2017) ("Abstract," pg. 2-8):

https://www.researchgate.net/publication/318373276_Biostratigraphy_and_biogeography_of_charophytes_from_the_Cerro_Barcino_Formation_upper_Aptian-lower_Albian_Canadon_Asfalto_Basin_central_Patagonia_Argentina

("Abstract"):

https://www.sciencedirect.com/science/article/abs/pii/S0195667117300836

Utricle Definition:

Palomar College. "Botany 115 Terminology: Fruit Terminology Part 3":
https://www2.palomar.edu/users/warmstrong/termfr3.htm

Merriam Webster. "Utricle":
https://www.merriam-webster.com/dictionary/utricle

Candiero et al., (2018) (Figure 1):
Krause et al., (2019) (P. 35 Figure 2, p. 39 Table 1, p. 40 Figure 6, p. 42):
http://staff.mef.org.ar/images/investigadores/diego_pol/papers/101.pdf
("Abstract"):

https://www.researchgate.net/publication/337297381_High-resolution_chronostratigraphy_of_the_Cerro_Barcino_Formation_Patagonia_Paleobiologic_implications_for_the_mid-cretaceous_dinosaur-rich_fauna_of_South_America

Link 2 ("Abstract"):
https://www.sciencedirect.com/science/article/abs/pii/S1342937X19302886
International Chronostratigraphic Chart (2019 Version):
http://stratigraphy.org/ICSchart/ChronostratChart2019-05.jpg
Link 2:
http://stratigraphy.org/index.php/ics-chart-timescale
Lips:
Reisz and Larson (2016) (Pg. 64-66):
https://cansvp.files.wordpress.com/2013/08/csvp-2016-abstract-book-compressed.pdf
Blake Eligh (2016):
https://www.utoronto.ca/news/did-dinosaurs-have-lips-ask-university-toronto-paleontologist
Mindy Weisberger (2016):
https://www.livescience.com/54912-did-t-rex-have-lips.html
Emanuela Grinberg (2016):
https://www.cnn.com/2016/05/22/world/dinosaur-lips-teeth-study/index.html
Phys (2016):
https://phys.org/news/2016-06-dinosaurs-lips.html
Tongue:
Mindy Weisberger (2018):
https://www.scientificamerican.com/article/t-rex-couldnt-stick-out-its-tongue/
ScienceDaily (2018):
https://www.sciencedaily.com/releases/2018/06/180620150129.htm
Hands:
Kenneth Carpenter (2002):
https://www.researchgate.net/publication/225366451_Forelimb_biomechanics_of_nonavian_theropod_dinosaurs_in_predation
Matt A. White et al., (2015) ("Discussion," p. 6):
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0137709
Speed:
Dececchi et al., (2020):
https://www.researchgate.net/publication/336117841_The_fast_and_the_frugal_Divergent_locomotory_strategies_drive_limb_lengthening_in_theropod_dinosaurs
EurekAlert (2020):
https://www.eurekalert.org/pub_releases/2020-05/p-trw051320.php
The Canadian Press (2020):
https://www.kamloopsthisweek.com/news/research-says-t-rex-was-built-for-long-distances-not-sprints-1.24134506
Prey:
Chubutisaurus:
Length:
https://psdinosaurs.blogspot.com/2018/12/size-calculations-for-herbivorous.html
Time:

***Krause et al., (2019) (P. 37, 40, and 42):

http://staff.mef.org.ar/images/investigadores/diego_pol/papers/101.pdf

Bonaparte and Gasparini (1978):
https://paleoglot.org/files/Bonaparte&Gasparini_79.pdf
Salgado (1993):
https://www.researchgate.net/publication/290798931_Comments_on_Chubutisaurus_insignis_Del_Corro_Saurischia_Sauropoda
*Weishampel et al., (2004) (Pg. 571):
https://www.researchgate.net/publication/234025996_Dinosaur_Distribution
Mannion and Calvo (2011) (Table 7):
https://academic.oup.com/zoolinnean/article/163/1/155/2625609
*Carrano et al., (2012) (Pg. 257-258): 
https://www.researchgate.net/profile/Matthew_Carrano/publication/230808558_The_phylogeny_of_Tetanurae_Dinosauria_Theropoda/links/0912f504a5960e5645000000/The-phylogeny-of-Tetanurae-Dinosauria-Theropoda.pdf?origin=publication_detail
*Fossilworks. "Bayo Overo Member" (105.3-99.7 Ma): 
http://fossilworks.org/bridge.pl?action=collectionSearch&formation=Cerro%20Barcino&member=Bayo%20Overo
Ligabuesaurus:
https://psdinosaurs.blogspot.com/2018/12/size-calculations-for-herbivorous.html
Amazonasaurus:
https://psdinosaurs.blogspot.com/2018/12/size-calculations-for-herbivorous.html
Enemies:
Genyodectes:
Rauhut (2004) (Pg. 895):

https://www.researchgate.net/publication/235907356_Provenance_and_anatomy_of_Genyodectes_serus_a_large-toothed_Ceratosaur_Dinosauria_Theropoda_from_Patagonia

Ezcurra and Novas (2016) (Pg. 145-146):
https://www.researchgate.net/publication/305011083_Theropod_dinosaurs_from_Argentina
Riley Black (2012):
https://www.smithsonianmag.com/science-nature/what-is-genyodectes-144686459/
Irritator:
Time:
Custodio et al., (2017) ("Abstract"): 
https://www.researchgate.net/publication/318770927_The_transgressive-regressive_cycle_of_the_Romualdo_Formation_Araripe_Basin_Sedimentary_archive_of_the_Early_Cretaceous_marine_ingression_in_the_interior_of_Northeast_Brazil
Varejao et al., (2019) (:Abstract"):
https://ui.adsabs.harvard.edu/abs/2019SedG..389..103V/abstract
Rodrigues et al., (2020) ("Abstract"):
https://www.sciencedirect.com/science/article/pii/S019566712030241X
Size:
https://psdinosaurs.blogspot.com/2018/10/calculations-for-largest-theropods.html
Angaturama is Likely Irritator:
Dal Sasso et al., (2005) (Pg. 894, Figure 3):
Specimen LPP-PV-0042:
Aureliano et al., (2018) (Pg. 4, 8, and 12):
Spent Time in Water:
Kristen Rogers (2020) ("Competing for food," p. 1):
https://www.cnn.com/2020/04/29/world/spinosaurus-swimmer-discovery-scn/index.html
Santanaraptor:
Time:
Custodio et al., (2017) ("Abstract"): 
https://www.researchgate.net/publication/318770927_The_transgressive-regressive_cycle_of_the_Romualdo_Formation_Araripe_Basin_Sedimentary_archive_of_the_Early_Cretaceous_marine_ingression_in_the_interior_of_Northeast_Brazil
Varejao et al., (2019) (:Abstract"):
https://ui.adsabs.harvard.edu/abs/2019SedG..389..103V/abstract
Rodrigues et al., (2020) ("Abstract"):
https://www.sciencedirect.com/science/article/pii/S019566712030241X
A Tyrannosauroid:
Delcourt and Grillo (2018) ("Abstract"):
https://www.researchgate.net/publication/327509211_Tyrannosauroids_from_the_Southern_Hemisphere_Implications_for_biogeography_evolution_and_taxonomy
Spectrovenator:
Zaher et al., (2020):
Link 2:

http://sciencepress.mnhn.fr/en/periodiques/comptes-rendus-palevol/19/6#:~:text=of%20the%20Abelisauridae-,An%20Early%20Cretaceous%20theropod%20dinosaur%20from%20Brazil%20sheds%20light,cranial%20evolution%20of%20the%20Abelisauridae&text=Abelisaurid%20theropods%20dominated%20the%20predator%20role%20across%20Gondwana%20during%20the%20Late%20Cretaceous.&text=Late%20Cretaceous%20abelisaurids%20are%20known,taxa%20with%20well%2Dpreserved%20skulls

Supplementary Information:

http://sciencepress.mnhn.fr/sites/default/files/documents/fr/comptes-rendus-palevol2020v19a6-additional-material.pdf

Time Period:
Corbella et al., (2004) ("Abstract;" "Characteristics and radiometric age of the tuff bed," p. 229):
Coria and Salgado (1995) (P. 226):
International Chronostratigraphic Chart (2020):

Lips:
Reisz and Larson (2016) (Pg. 64-66):
https://cansvp.files.wordpress.com/2013/08/csvp-2016-abstract-book-compressed.pdf
Blake Eligh (2016):
https://www.utoronto.ca/news/did-dinosaurs-have-lips-ask-university-toronto-paleontologist
Mindy Weisberger (2016):
https://www.livescience.com/54912-did-t-rex-have-lips.html
Emanuela Grinberg (2016):
https://www.cnn.com/2016/05/22/world/dinosaur-lips-teeth-study/index.html
Phys (2016):
https://phys.org/news/2016-06-dinosaurs-lips.html
Tongue:
Mindy Weisberger (2018):
https://www.scientificamerican.com/article/t-rex-couldnt-stick-out-its-tongue/
ScienceDaily (2018):
https://www.sciencedaily.com/releases/2018/06/180620150129.htm
Hands:
Kenneth Carpenter (2002):
https://www.researchgate.net/publication/225366451_Forelimb_biomechanics_of_nonavian_theropod_dinosaurs_in_predation
Matt A. White et al., (2015) ("Discussion," p. 6):
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0137709
Skull:
NBC (2006):
http://www.nbcnews.com/id/12356665/ns/technology_and_science-science/t/huge-dinosaurs-roamed-argentina-groups/#.XlQBxraZOu4
Speed:
Dececchi et al., (2020):
https://www.researchgate.net/publication/336117841_The_fast_and_the_frugal_Divergent_locomotory_strategies_drive_limb_lengthening_in_theropod_dinosaurs
EurekAlert (2020):
https://www.eurekalert.org/pub_releases/2020-05/p-trw051320.php
The Canadian Press (2020):
https://www.kamloopsthisweek.com/news/research-says-t-rex-was-built-for-long-distances-not-sprints-1.24134506
Taurovenator is G. (Mapusaurus) roseae:
Motta et al., (2016):
https://www.researchgate.net/publication/304013683_NEW_THEROPOD_FAUNA_FROM_THE_UPPER_CRETACEOUS_HUINCUL_FORMATION_OF_NORTHWESTERN_PATAGONIA_ARGENTINA
The Theropod Database. "Mapusaurus roseae." "Comments":
https://www.theropoddatabase.com/Carnosauria.htm#Mapusaurusroseae
Coria et al., (2019) (Discussion para. 4):
https://www-sciencedirect-com.proxy-um.researchport.umd.edu/science/article/pii/S0195667119303957?via%3Dihub
Date:
https://www.researchgate.net/publication/337514360_An_Early_Cretaceous_medium-sized_carcharodontosaurid_theropod_Dinosauria_Saurischia_from_the_Mulichinco_Formation_upper_Valanginian_Neuquen_Province_Patagonia_Argentina
Prey:
Argentinosaurus:
Time:
Carballido et al., (2017): 
http://rspb.royalsocietypublishing.org/content/284/1860/20171219
Riga et al., (2016):
https://www.nature.com/articles/srep19165
Lacovara et al., (2014):
https://www.nature.com/articles/srep06196
Size:
https://psdinosaurs.blogspot.com/2018/12/size-calculations-for-herbivorous.html
Cathartesaura:
Time:
Gallina and Apesteguia (2005):
https://www.researchgate.net/publication/262637167_Cathartesaura_anaerobica_gen_et_sp_nov_a_new_rebbachisaurid_Dinosauria_Sauropoda_from_the_Huincul_Formation_Upper_Cretaceous_Rio_Negro_Argentina
Size:
https://psdinosaurs.blogspot.com/2018/12/size-calculations-for-herbivorous.html
Anabisetia:
Coria and Calvo (2002):
https://www.researchgate.net/publication/233127594_A_new_iguanodontian_ornithopod_from_Neuquen_Basin_Patagonia_Argentina
Enemies:
Skorpiovenator:
Time:
Canale et al., (2009):
https://www.researchgate.net/publication/23572798_New_carnivorous_dinosaur_from_the_Late_Cretaceous_of_NW_Patagonia_and_the_evolution_of_abelisaurid_theropods
Size:
https://psdinosaurs.blogspot.com/2018/10/calculations-for-largest-theropods.html
Gualicho:
Apesteguia et al., (2016):
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0157793
Spinosaurus quilombensis:
Posted by at

Wednesday, September 13, 2017

Dino Bios: Spinosaurus.

Spinosaurus:
Time: 113-94 million years ago; Albian-Cenomanian of the early-late Cretaceous period.
Place: South America and Africa.
Size: 27-46 feet (8.1-14.1 meters). 
Weight: 3.6-7.2 tons (based on MSNM V4047). 
Diet: Piscivore.
Additional Species:
1. S. (Oxalaia) quilombensis.

Let's talk about Spinosaurus, probably the most confusing, and most heavily debated, dinosaur of all time!

Description:
Spinosaurus lived in the Albian-Cenomanian of the early-late Cretaceous period, 113-94 million years ago. It was 27-50 feet long (8.1-15.1 meters), and weight 3.6-7.2 tons. It had a long and slender skull that were filled with conical-shaped teeth. These jaws were designed to catch fish. Its nostrils were positioned below its eyes, allowing Spinosaurus to keep its snout in the water without the fear of drowning. Spinosaurus' eyes sat on the top of its head, which would have helped it to see while submerged in the water. This helps to conclude that Spinosaurus was indeed semi-aquatic (Arden et al., 2018). Sereno et al., (2022) have concluded that Spinosaurs was semi-aquatic but not an aquatic predator (Abstract; Conclusions). Fabbri et al., (2022) says that it was, given the extremely thick bone density of the animal (pp. 854 and 856; Figures 1 and 3). 

Its neck was long and slender. This would have helped Spinosaurus to catch its prey, presumably by using its long neck to shove its snout at fish. Its arms were long and equipped with sharp claws. These would have been good for slicing fish open (Ibrahim et al., 2014, pg. 1613-1614). However, Hone and Holtz (2017) said that Spinosaurus' (and other spinosaurids') arms could not reach up to its snout, so using its arms and claws to catch prey wouldn't seem to work. Also their lack of grasping capabilities seem to hinder their ability to catch prey as well. However, they seem to have been good for digging to make nests or for prey buried in the ground (pg. 1128). They might have even been used for intimidation, but this is speculative (pg. 1129, Figure 6).

The legs of Spinosaurus were short but muscular, used for traversing through the water. The toes on its feet were flat and webbed, like a penguin's or a crocodile's (Ibrahim et al., 2014, pg. 1614-1615). Some people think that Spinosaurus did like water, but it couldn't swim like a crocodilian. It would have stayed near the shore, or go into shallow water, and hunt fish that way (The Atlantic, 2016) (Donald M. Henderson, 2018). Kenneth Carpenter in 2014 said that the water would not be deep enough for it to swim, and it would only be "hip-deep" (Phys, 2014). Sereno et al., (2022) concluded that Spinosaurus was bipedal, and traveled across land just fine (Abstract). The short legs were for carrying its weight (Conclusions, 2). Fabbri et al., (2022) maintains that Spinosaurus' body design was geared towards an aquatic lifestyle (pp. 856-857). 

Spinosaurus had a long tail that would have been used to help it swim in the water (Ibrahim et al., 2014, pg. 1616). Ibrahim et al., (2020) (Tail-propelled aquatic locomotion in a theropod dinosaur)
discovered Spinosaurus tail vertebrae that show that it had a fin on its tail ("Abstract") ("A Swimming Dinosaur: The Tail of Spinosaurus," 2:41-2:48). It's tail was comparable to "crocodiles and newts" ("A Swimming Dinosaur: The Tail of Spinosaurus," 3:11-3:20) (Jackson Ryan, 2020, p. 8), and it would have allowed Spinosaurus to hunt prey underwater (Jackson Ryan, 2020, p. 4) (Will Dunham, 2020, p. 1 and 6). It was probably like a crocodile (Will Dunham, 2020, p. 11) (Carolyn Gramling, 2020, p. 1). Sereno et al., (2022) said that Spinosaurus was not an aquatic dinosaur, but a "semiaquatic bipedal ambush piscivore that frequented the margins of coastal and inland waterways." It wasn't an underwater pursuit predator (Abstract; Conclusions, 4 and 6-8). The tail was a "pliant billboard than flexible fluke" for swimming (Conclusions, 3). Fabbri et al., (2022) maintains that the tail was for swimming (p. 852).

Carnivorous theropod dinosaurs had enamel in their teeth, so they must have had lips to cover and protect their teeth (Reisz and Larson, 2016, pg. 64-66) (Blake Eligh, 2016) (Mindy Weisberger, 2016) (Emanuela Grinberg, 2016) (Phys, 2016). Therefore, Spinosaurus would have had lips covering its teeth. Interestingly, dinosaurs couldn't move its tongues (Mindy Weisberger, 2018) (ScienceDaily, 2018).

Oxalaia, a spinosaur from South America (Kellner et al., 2010), is now considered to be Spinosaurus (Smyth et al., 2020, "Abstract"). Most of the Spinosaurus skeletons come from Africa, but now Spinosaurus material is coming from South America as well. I would say, based on location, "Oxalaia 
quilombensis" can be considered Spinosaurus quilombensis.

Spinosaurus teeth, discovered from the Ifezouane and Aoufous Formations of the Kem Kem Beds, outnumber other fossils discovered in the site, including Onchopristis. With a lack of other terrestrial theropod, and even aquatic animal, fossils at the two sites, it is suggested that Spinosaurus is either largely aquatic, or even completely aquatic (Beevor et al., 2020, "Abstract," Table 1A-B, "Discussion: Relative Abundances," "Conclusions") (Sci News, 2020, p. 15) (Carly Cassella, 2020, p. 8 and 13). Egg-laying would have been the only reason for Spinosaurus to venture onto land. Sereno et al., (2022) have stated that Spinosaurus spent more time on land than near water, based on the locations of the fossils (Abstract; Conclusions), despite the fact that the animal seems to be designed for life in the water (Fabbri et al., 2022, pp. 852, 856-857).
Spinosaurus Holotype IPHG 1912 VIII 19 (Ernst Stromer, 1915, Article 3, pg. 35, Table 1):
Spinosaurus Tail (Ibrahim et al., 2020b, Tail-propelled aquatic locomotion in a theropod dinosaur, pg. 2, Figure 1):
Size:
Spinosaurus' size has fluctuated over the years. Dal Sasso et al. (2005), when the specimen MSNM V4047 was discovered, gave Spinosaurus a length of 16-18 meters and a weight of 7-9 tons (pg. 895). This was based on the specimen MSNM V4047. However, Francois Therrien and Donald M. Henderson, in the paper My Theropod Is Bigger Than Yours... Or Not: Estimating Body Size From Skull Length In Theropods, in 2007, gave MSNM V4047 a length of 12.6-14.3 meters long and a weight of 11,987-20,887 kilograms (13.2-23 tons) (pg. 111). They stated that, "A revised body size estimate for a large Spinosaurus specimen suggests a much shorter and heavier animal than recently suggested," ("Abstract").

In 2014, Spinosaurus was given a length of 49 feet (15.0 meters) (Ibrahim et al., 2014 pg. 1613 and Supplementary Materials pg. 9) to 50 feet (15.2 meters) (Paul Sereno, "Spinosaurus aegyptiacus"). Sereno gave a body mass of 7.5 tons. In 2018, Donald M. Henderson (2018) gave the skeleton a length of 15.6 meters ("Materials and Methods," p. 1).

Evers et al., (2015) stated that the reconstructed Spinosaurus skeleton, built by Ibrahim et al., (2014), had the bones of Sigilmassasaurus in it (Evers et al., 2015,  "The 'neotype' of Spinosaurus aegyptiacus"). Hendrickx et al., (2016) agreed with this (Hendrickx et al., 2016, "Diversity," p. 6). Arden et al., (2018) said that Sigilmassasaurus was larger than Spinosaurus, and assigned MSNM V4047 to Sigilmassasaurus ("Phylogenetic Analysis," p. 4-5), but Larkin and Longrich (2018) stated that MSNM V4047 didn't belong to Spinosaurus or Sigilmassasaurus (p. 139). Therefore, it seemed that the longest species of spinosauridae is an undetermined species and not Spinosaurus. Ibrahim et al., (2020b) stated that Sigilmassasaurus was Spinosaurus.

Update (4/24/20-4/26/20): Ibrahim et al., (2020a) (Geology and paleontology of the Upper Cretaceous Kem Kem Group of eastern Morocco) wrote a VERY long paper about prehistoric African animals from the Kem Kem Group of Morocco, Africa. In the "Spinosauridae" category of the "Taphonomy" section of their paper, they've refuted Arden et al., (2018) and Evers et al., (2015) in establishing Sigilmassasaurus as a separate species, and concluded that only one genus of spinosaurid existed in the Kem Kem Group: Spinosaurus. They reassigned "Sigilmassasaurus," "Spinosaurus marocannus," and "Spinosaurus B" to Spinosaurus aegyptiacus now. So until further notice, "Sigilmassasaurus" is now Spinosaurus. 

I obtained a body length of 29-47 feet (8.8-14.2 meters), which is supported by Sereno et al., (2022) whom gave it a body length of 14 meters (Conclusions, 1):
Specimens:
1. IPHG 1912 VIII 19 (Holotype):
Photo from Stromer (1936) (P. 65):
Length: 27 feet (8.1 meters).

 2. 1922 X 45 ("Spinosaurus B"):
Length: 31 feet (9.3 meters).

3. FSAC-KK 11888 (Neotype):
Length: 34 feet (10.3 meters). 
Age: 17.
Age 18: 35 feet (10.7 meters)(?). (My estimate)

 This specimen was discovered in 2014 by Ibrahim et al., (2014), and was a subadult at 17 years of age (Supplementary Materials, pg. 14).

4. MHNM.KK378:
Length: 31 feet (9.5 meters).
Age: Adult.

5. MNHM SAM 124:
Length: 40 feet (12.1 meters).

6. BSPG 2011 I 118:
Length: 46 feet (14.1 meters).

7. MSNM V4047:
Length: 46 feet (14.0 meters).

8. MN 6117-V (S. quilombensis):
Length: 39 feet (11.9 meters).

9. NHMUK VP R 16421:
Length: 41 feet (12.5 meters).

10. MHNM.KK376:
Length: 29 feet (8.8 meters).

It seems that, during the Cenomanian, the larger spinosaurids evolved and took over the rivers, driving the giant crocodylomorphs, like Sarcosuchus, into extinction (Arden et al., 2018, "Abstract"). This could to be the reason why Spinosaurus grew so large in the Cenomanian.

Sail:
And now, the sail. The sail is a mystery and many hypotheses have been proposed for it. However, in the 2016 paper The riddle of Spinosaurus aegyptiacus' dorsal sail, written by Gimsa et al., it was hypothesized that Spinosaurus used its sail to help it stay submerged in the water, and to give it more power and maneuverability in its neck and tail ("Abstract," Figure 1). This would've helped Spinosaurus to stun or injure its prey with its jaws or tail. Sailfish use their sails the same way, and thresher sharks use their tails to help capture prey. They also suggest that Spinosaurus' sail acted like a screen that helped Spinosaurus to encircle prey underwater, and then capture it. 

In fact, Spinosaurus' sail looks like a sailfish's sail.

 Sailfish:
Spinosaurus Submerged and Swimming (Gimsa et al., 2016):
The sail could have also acted like a ship's keel, which would have given Spinosaurus stability in the water (Andrew Whalen, 2020, p. 9).

Update (5/4/21): Holtz told me today after class that Spinosaurus' sail might be a sexual dimorphic trait that only males have. Females might not have them. I asked him if Sigilmassasaurus might be a female Spinosaurus, since most depictions show it without a sail. He says it's a possibility, but not conclusive. With that in mind, Sigilmassasaurus could be a female Spinosaurus. This is speculation though, but I find the idea to be very fascinating. The sail could also have changed color, according to Holtz as well.

Update (6/19-22/22): Sereno et al., (2022) have given Spinosaurus a circular-shaped sail again (Figure 1, A-E):
However, Fabbri et al., (2022) kept Ibrahim et al., (2020b)'s design for the sail.

Locomotion:
It is interesting to note that when Spinosaurus was first discovered, it was thought that it was a quadruped. In fact, it looked like Dimetrodon (Donald F. Glut, 2001, pg. 82).

Spinosaurus from 1970's(?) as described in Donald F. Glut (2001) (Pg. 82):
However, after Suchomimus and Baryonyx were discovered, scientists realized that Spinosaurus looked like them (Glut, 2001, pg. 84) (Charig and Miller, 1997, pg. 55-57). They used Suchomimus' and Baryonyx's body design to come up with a new look for Spinosaurus (Glut, 2001, pg. 84), this time with a bipedal look (Charig and Miller, 1997, pg. 12 and 55) (Sereno et al., 1998, pg. 1300):
But after its re-discovery in 2014, Spinosaurus has been depicted as walking on all fours again. Primarily, it was shown walking on its knuckles like an anteater or sloth. The reasons for this was stated by Ibrahim et al., (2014), and by Paul Sereno in the YouTube video Rediscovering Spinosaurus: The First Semi-Aquatic Dinosaur. They stated that Spinosaurus' legs were not efficient enough for it to walk as a biped on land, and Nizar Ibrahim said that Spinosaurus would have used its arms to help support its weight. Spinosaurus' arms were about the same size as its legs. Sereno in the video also stated that, when creating a computer model of the animal, it could not support itself on its hind limbs alone.

More information on Spinosaurus' anatomy was explained in Ibrahim et al., (2014):

1. "We note here that Spinosaurus must have been an obligate quadruped on land, the first discovered among theropod dinosaurs, given the usual horizontal sacroiliac joint and the anterior location of the estimated center of body mass," (pg. 1615).

2. "The center of mass in a biped must be located over the middle one-third of the pes to generate a plausible mid-stance pose. In our flesh rendering of Spinosaurus, the center of body mass is positioned in front of both the hip and knee joints at a distance greater than femur length, suggesting that forelimb support was required during terrestrial locomotion. Spinosaurus appears to have been poorly adapted to bipedal terrestrial locomotion. The forward position of the center of mass within the rib cage may have enhanced balance during foot-propelled locomotion in water," (pg. 1615). 

3. "Reduction of the pelvic girdle and hindlimb and the concomitant enhancement of axial-powered locomotion are common among semiaquatic vertebrates," (pg. 1616). 

Spinosaurus' Posture After Ibrahim et al., (2014) (David Bonadonna):
The 2014 reconstruction was met immediately with skepticism. It was argued that a quadrupedal Spinosaurus doesn't seem probable (Scott Hartman, September 13, 2014, p. 11), which led to other paleontologists to reconstruct Spinosaurus themselves. Some made it a biped (Andrea Cau, 2014 and 2015), while others stated that the legs were incorrectly scaled and should be longer (Scott Hartman, September 12, 2014). Some said that Spinosaurus could "combat crawl" (Duane Nash, August 16, 2014) (Duane Nash, September 14, 2014). This means that Spinosaurus, basically, would belly-slide on land like a loon. The internet basically attacked Ibrahim and his team (Scott Hartman, September 13, 2014, p. 13). However, the legs were proven to have been small (Hartman, September 18, 2014). In 2017, Ibrahim and his team reviewed the neotype's skeleton, and concluded that the bones came from one individual animal that was a subadult. Therefore, the leg lengths for the neotype are valid (Fabbri et al., 2017):
The reason for having Spinosaurus being portrayed as  quadruped originally by Ibrahim et al., (2014) was that, in the Supplementary Materials of their paper on page 24, it is shown that Spinosaurus' center of gravity (represented by a red dot) is in the middle of its body, not at its hips like other theropods. Therefore, Spinosaurus would be leaning forward a lot.

Spinosaurus' Center of Gravity (Red Dot) (Ibrahim et al., 2014, Supplementary Materials, pg. 24):
However, Donald Henderson (2018) wrote a paper saying that Spinosaurus' center of gravity was closer to its hips, like other bipedal theropods, allowing it to walk as a biped ("Abstract," Figure 1, "Results" p. 1). He gave 0.3182 for its center of mass (Figure 7), which is similar to other theropods (Figure 1).

Spinosaurus' Center of Gravity (Henderson, 2018, Figure 1):
From what I can tell, although this seems to be a "slam dunk" as to whether or not Spinosaurus could walk as a biped, Henderson (2018) does have some problems though. First, Henderson blamed the new body proportions given to Spinosaurus, by Ibrahim et al., (2014), as a result of incorrectly using other species of spinosaurids in reconstructing the skeleton ("Discussion," p. 7-8). Fabbri et al., (2017) proved that Spinosaurus did indeed have short legs, so this critique is incorrect. Second, Henderson got the center of mass for Spinosaurus closer to its legs (Figure 1, Figure 11), but he got the center of mass for Spinosaurus' sail in the middle of Spinosaurus' stomach (Figure 2). Shouldn't it be the same for the sail and legs? This seems to be ignored ("Results" p. 1, "Discussion" p. 2-3). 

 Spinosaurus Center of Mass for It's Sail (Henderson, 2018, Figure 2):
Henderson used a pigeon and an ostrich to confirm this ("Discussion" p. 2-3, Figure 11), but Spinosaurus is not closely related to either of those animals like other theropods are. Once again, Fabbri et al., (2017) says that Spinosaurus is closer to penguins. Henderson did say that the penguin's center of mass was in the middle of its belly (Figure 4), so it should be the same for Spinosaurus, as Ibrahim et al., (2014) did (Supplementary Materials, pg. 24, Figure S3). 

 Third, Henderson compared Spinosaurus to other theropods like T. rex, Suchomimus, and even an alligator in order to see how well Spinosaurus could float. He said that Spinosaurus could only float just as good as those other two dinosaurs (Figure 5, "Discussion" p. 4), and that Spinosaurus would tip over in the water unlike an alligator based on its center of mass and metacentric height ("Results" p. 6, Figure 7). However, Ibrahim et al., (2014) said that Suchomimus and T. rex were not like Spinosaurus, due to the short hind limbs and thickness of the bones. Those two dinosaurs seem to have had a more terrestrial lifestyle than Spinosaurus did. Also, Spinosaurus' bones were more dense than an alligator's, so it should have floated just as good as an alligator (Supplementary Materials, pg. 14-15). Henderson got an alligator's center of mass close to its legs (Figure 3), but alligators are still quadrupedal (Reilly and Blob, 2003, "Abstract"). Alligators can do a trot on land, but this is because their tails are dragging on the ground. Also, their tails and limbs have "individual reaction forces" that help them, which "is consistent with the more caudal location of its center of mass" (Willey et al., 2004, "Summary") (Reilly and Blob, 2003, "Abstract"). Dinosaurs didn't drag their tails (David Hone, 2012), so Spinosaurus couldn't drag its tail to walk like a biped on land. Also, trotting is something that is done on all fours, as defined by Merriam-Webster. Crocodilians do have large feet, which allows the "ground reaction force to shift farther from the limb joints" in an upright posture (Reilly and Blob, 2003, "Abstract"). In 2012, a crocodile in Africa was photographed standing on its hind legs, but this was only to grab food held out by visitors. Once it got its food, it went back onto its stomach (Alex Ward, 2012, p. 9). However, Spinosaurus' feet are either about the same, or slightly smaller, than its hands, with pedal unguals 2-4 being the same size as pedal ungual/digit 1, which is the smallest toe on a theropod's foot. Usually for theropods, unguals 2-4 are larger than ungual/digit 1 (Ibrahim et al., 2014, pg. 1614-1615, p. 8-10). Also, if Spinosaurus' posture was similar to a crocodilian's, then it wouldn't be able to stand in a bipedal pose for very long at all.

 With the information I have, and from what paleontologist Duane Nash said about his "combat crawl" for Spinosaurus, I think Spinosaurus used belly-sliding on land, similarly to a loon, crocodilians, otters, and penguins. Given that its habitat was a swamp or near a river, it would have had to deal with a muddy environment. Loons and crocodilians live in the same habitats. Loons always stay near water (Alina Bradford, 2016, "Habitat"), and crocodiles live near "lakes, rivers, wetlands, and even some saltwater regions" (Bradford, 2014, "Where do crocodiles live?"). For loons, given that their short limbs that makes walking on land very hard (Alina Bradford, 2016, "Description") (U.S. Fish and Wildlife Refuge, "Common Loons," "Nesting"), they tend to "move one foot forward at a time" with their bellies on the ground, or they belly-slide to help get themselves in the water (West Pond Association, "The Common Loon," "Daily Life' p. 4). I think Spinosaurus would have done the same thing. Plus, penguins and loons have thick bones, and feet placed at the anterior part of their bodies, like Spinosaurus did (Loon Preservation Committee, "Common Loon Plumage and Appearance," p. 1) (International Penguin Conservation and Work Group, "Introduction to Penguins," p. 2). Penguins would also belly-slide, also known as tobogganing, rather than walk, since it conserves energy (Wilson et al., 1991, "Abstract") (Gill and Prevost, "Penguin: Natural History: Locomotion and orientation,” Encyclopaedia Britannica) (New England Aquarium, 2016, "Penguins Teacher Guide: Physical Characteristics” pg. 2 p. 3) (Sea World Parks and Entertainment, "All About Penguins: Physical Characteristics: Legs and Feet” p. 3). Since Spinosaurus and a penguin have similar center of masses and bone densities (Ibrahim et al., 2014, Supplementary Materials, pg. 24, Figure S3) (Fabbri et al., 2017) (Henderson, 2018, Figure 4), it seems more likely that Spinosaurus acted more like a loon or penguin on land, and belly-slide in order to conserve energy. At best, it probably walked by moving one foot forward at a time while having its belly on the ground.

 Loon:
Penguin Toboganning:
Penguin's Center of Mass (Henderson, 2018, Figure 4):
For crocodilians, despite having a center of mass closer to its legs (Henderson, 2018, Figure 3), crocodiles use the belly crawl as their main mode of transportation on land (Adam Britton, 1996, p. 1). They put their whole bodies on the ground, and their legs help to push them across the ground (p. 2). They can either be slow, or move at "5 to 10 kph" (3.1-6.2 mph) (p. 1). At higher speeds, their bellies can be lifted of the ground a little bit to "reduce friction" (p. 4). This helps the crocodile to get into the water "when sliding down an embankment into a river, lake, or pond" (Marshall Cavendish, 20011, pg. 60) (Sally M. Walker, 2004, pg. 17), and when they're scared (Sally M. Walker, 2004, pg. 17). Gharials belly-slide on land because they have "weak leg muscles," which means they are "poorly equipped for locomotion on land." They do most of their transportation via water (Smithsonian National Zoo and Conservation Biology Institute, "Gharial," "Conservation," "Physical Description" p. 3). 

Alligator Center of Mass (Henderson, 2018, Figure 3):
Crocodile Getting Into Water on Its Belly:
Crocodile Getting Out of Water on Its Belly:
Otters, like the loon, penguin, and crocodilians, have an elongated body and short legs. It's long tail helps the otter to swim, along with its webbed feet. On land, they are fast but they can move faster by belly-sliding (The National Wildlife Federation, "North American River Otter," Description p. 1). They slide in ice and mud (The National Wildlife Federation, "North American River Otter," Description p. 1) (San Francisco Zoo, "North American River Otter," Fun Facts). They can do this for fun (The National Wildlife Federation, "North American River Otter," Description p. 1), or to escape from enemies (Ernest Thompson Seton, 1909, "The Canada Otter," pg. 829). This seems to make the otter faster than a human (Ernest Thompson Seton, 1909, "The Canada Otter," pg. 829). Using this information, it sounds more plausible that Spinosaurus, while belly-sliding through the mud, would be faster than, and escape from, the two-legged Carcharodontosaurus and Bahariasaurus.

Otter Belly-Sliding:
There are other spinosaurids that seem to have done this as well. Aureliano et al., (2018) describes a spinosaurid (Irritator?) specimen from South America, called LPP-PV-0042, that had a small tibia that was dense like Spinosaurus' (pg. 8 and 12). It seems possible that this spinosaurid might have been belly-sliding as well. Also, Evers et al., (2015) reports that the specimen "Spinosaurus B," which seems to belong to Sigilmassasaurus, had a tibia only 60 cm long (Backed up in Stromer, 1934, pg. 16). However, they said that if spinosauridae did have short limbs, then it did belong to "Spinosaurus B" ("'Spinosaurus B' and Sigilmassasaurus," pg. 64). Short legs have been proven true for spinosauridae (Fabbri et al., 2017, pg. 109), so it seems that Sigilmassasaurus had short hindlimb too ("'Spinosaurus B' and Sigilmassasaurus"). Therefore, it seems that Sigilmassasaurus was a belly-slider as well, or at least walked by moving one foot forward at a time.

Update (4/24/20-6/18/20): Ibrahim et al., (2020) (Geology and paleontology of the Upper Cretaceous Kem Kem Group of eastern Morocco), Smyth et al., (2020), and Ibrahim et al., (2017) conclude that "Sigilmassasaurus" and "Spinosaurus B" are synonyms of Spinosaurus now. Therefore, "Sigilmassasaurus" had short legs too, since it is Spinosaurus.

Update (4/24/20): Spinosaurus' new tail, as described in Ibrahim et al., (2020) (Tail-propelled aquatic locomotion in a theropod dinosaur), prevented Spinosaurus from rolling over (Jackson Ryan, 2020, p. 9). This solves the "tipping over" problem mentioned by Henderson (2018) ("Results" p. 6, Figure 7). Also, it has been said, once again, that Spinosaurus needed help walking on land (Will Dunham, 2020, p. 10).

 Ibrahim et al., (2020) (Tail-propelled aquatic locomotion in a theropod dinosaur) also redid Spinosaurus' center of mass/gravity, and it appears to be closer to the middle of its body again, as reported in Ibrahim et al., (2014) (Supplementary Materials, pg. 24). In Ibrahim et al., (2014), the center of mass was 1.04 m. In Henderson (2018), it was 0.3182 in Figure 7, but the authors give 0.48 m. Now it's 0.725-0.825 m (Ibrahim et al., 2020, Extended Data Figure 8, "B"-"D"). This seems to back up what was said in Dunham (2020) about needing support for walking (p. 10). Jason Treat and Mesa Schumacher (2020) says that "Spinosaurus' center of gravity leans forward, which aids swimming, and its curved claws are more suited for catching prey in the water than for walking on land." Ibrahim et al., (2020) (Tail-propelled aquatic locomotion in a theropod dinosaur; Supplementary Materials, pg. 31, "Body mass, segment masses, and centre of mass (CoM)") says that  the new COM supports their 2014 conclusion that Spinosaurus needed support for walking on land, and that "a facultative, if not completely, quadrupedal gait on land" is necessary. Also, an animal that has a COM that is greater than their femur length will hinder bipedal locomotion, and even standing, on land.

Quote from Ibrahim et al., (2020) (Tail-propelled aquatic locomotion in a theropod dinosaur; 
Supplementary Materials, pg. 31, Body mass, segment masses, and centre of mass (CoM), p. 31):
Just in case, I decided to measure the ilium and femur of FSAC KK 11888 in Ibrahim et al., (2020)(b) (p. 2, Figure 1), and I got 70 cm for the ilium and 60 cm for the femur. I measured them again in Ibrahim et al., (2020)(a) (Figure 129), and I got 71 cm for the ilium and 66 cm for the femur. Then in Ibrahim et al., (2014) (p. 1614, Figure 2), I got 79 cm for the ilium and 62 cm for the femur. These sizes are either almost the same size, or only slightly larger than, the ilium of Allosaurus specimen USNM 4734 (72 cm) (Gilmore, 1920, p. 66), but its femur is 85 cm (p. 69). USNM 4734 is 7.9 meters long. The ilium of Baryonyx is 83.5 cm (Charig and Miller, 1997, pg. 47), and its body length is 7.6 meters long. FSAC is 10.3 meters long. The leg muscles of Spinosaurus wouldn't be able to carry its weight on land. Paleo-artist Luis V. Rey suggested this first on his blog ("Spinosaurus Revisited Part 2. Spinosaur hysteria!").

 Otero et al., (2019) studied the locomotive history of the sauropodomorph Mussaurus. After studying different specimens from various ontogenetic ages (young to adults), it seems that the young were quadrupedal but the adults were bipedal. When they're young, Mussaurus' center of mass (CoM) was positioned in the middle of the animal's body, and the CoM was greater than the animal's femur length. This would make the young Mussaurus a quadruped. As they grew into an adult, their CoM would get shorter than the length of their femur, and closer to their hips, making it a biped. In fact, the CoM has to be less than one of the animal's femur length in order for it to be bipedal ("Abstract," Figure 2, "Discussion" p. 1 and 4). Spinosaurus' CoM (0.725-0.825 m) is still greater than one length of the animal's femur (0.625 m) (Ibrahim et al., 2020, "Body dimensions, body body mass, body segment masses, and whole body centre of mass" pg. 1). 

Therefore, with its center of mass/gravity tipping it forward, and its claws not suited for walking on land, it seems that my loon/penguin mode of transportation for Spinosaurus could help solve this. Walking by putting one foot forward while its belly is on the ground/belly-sliding, Spinosaurus wouldn't need to use its hands and it would have had the support it needed to maneuver on land.

Spinosaurus' Center of Mass (Ibrahim et al., 2020b) ("B" is new COM, "C" is Henderson (2018) COM, and "D" is Ibrahim et al., (2014) COM):
Of course, some people say otherwise. Mark Witton (2020) says that the new COM from Ibrahim et al., (2020) means that Spinosaurus was closer to being a biped, and a speculative quadruped ("Spinosaurus 2020: thoughts for artists," "Posture and balance" p. 1-2). This is not what Ibrahim et al., (2020) said. They said that Spinosaurus was more than likely a quadruped (look above). Witton also thinks that more testing could result in a strictly bipedal Spinosaurus altogether ("Spinosaurus 2020: thoughts for artists," "Posture and balance" p. 1-2). However, Witton did some calculations of his own, and says that Spinosaurus' legs wouldn't be able to carry an animal that was over four tons, and the animal's legs would have to be straight and not bend in order to support itself as a biped ("Posture and balance" p. 3):
The neotype is speculated to weigh 3.6-4.6 tons (Ibrahim et al., 2020, Supplementary Materials, pg. 31). If it was in a vertical posture, as proposed by Andrea Cau in 2014-2015, and didn't bend its legs, then it could support itself. In any other posture, Witton says that its legs wouldn't be able to support its weight ("Spinosaurus 2020: thoughts for artists," "Posture and balance," p. 2-3). My question is, if the neotype's legs wouldn't be able to support its body unless it was in a vertical posture and its legs were straight, and its mass was not above four tons, then how would the even larger specimens like MSNM V4047 be able to support themselves? Henderson (2018) gave MSNM V4047 a weight of 6,500 kg (7.2 tons) (Table 2). Sereno et al., (2022) gave a weight of 7,390 kg (8.15 tons) (Results: S. aegyptiacus flesh model form and function, para. 3). What about the neotype being 4.6 tons instead of just 4? This, along with the "completely straight legs" argument, makes a "strictly bipedal" Spinosaurus seem unrealistic, despite some people desperately wanting it to be. This was stated by Duane Nash in 2016 (March 9, 2016, p. 5-8).

Also, here's more proof that the scientists behind Ibrahim et al., (2020) said that Spinosaurus leaned more towards quadrupedalism rather than bipedalism. Stephanie E. Pierce and George V. Lauder, two "professors of organismic and evolutionary biology from Harvard," as stated in Clea Simon (2020), built a computer model of Spinosaurus. Pierce said that Spinosaurus' center of mass would have made Spinosaurus "tip forward if it were on land, a dynamic that fits with the short legs" (p. 10):
Perhaps new data will reveal a "strictly bipedal" Spinosaurus in the future, but the data we have now shows that Spinosaurus would have needed help walking on land. I'm going to stick with the belly-sliding posture until further notice.

Update (10/27/20): Gharials are a genus of crocodilian that have weak leg muscles that prevent them from walking on land like other crocodilians. They have to push themselves across the land by belly sliding. They rely on swimming for transportation (Smithsonian National Zoo & Conservation Biology Institute, "Gharial," "Physical description" p. 3) (Animal Diversity Web, "Gavialis gangeticus Gharial," "Habitat," "Physical Description"). They are also have an aquatic lifestyle, and only come onto land to bask and nest ("Native Habitat" p. 2). Adults are primarily piscivorous, while the young eat a variety of smaller animals ("Food/Eating Habits"). 

I think this is another great example of what Spinosaurus' lifestyle would've been like, if not the best one, and it's another reason why I support belly sliding for Spinosaurus whenever it came onto land.

Update (12/17/20): Scott Hartman has, once again, criticized the neotype specimen. He has stated that he thinks the neotype specimen might not be Spinosaurus, and, even though he admits that he might have to check his numbers again, he has resolved to using the tibia length of "Spinosaurus B" in his reconstruction of Spinosaurus, since the neotype's leg proportions don't seem to match it ("The Road to Spinosaurus III: Of Chimeras and Leg Proportions: Of Chimeras and FSAC-KK-1188" p. 1; "Leg Proportions" p. 8; "Conclusions" p. 1-2). This has produced, according to his results, a Spinosaurus with longer legs, making it a biped ("The Road to Spinosaurus IV: Not Your Father's JP3 Spinosaurus").

Scott Hartman's Reconstruction of Spinosaurus ("The Road to Spinosaurus IV: Not Your Father's JP3 Spinosaurus"):
However, "Spinosaurus B" has a tibia that is 60 cm long (Stromer, 1934, pg. 16) (Evers et al., 2015, 
"'Spinosaurus B' and Sigilmassasaurus," pg. 64) This produces an animal that is 31 feet long (9.3 meters). The neotype has a tibia that is 66.8 cm long (Ibrahim et al., 2014, "Supplementary Materials" pg. 33), and is 10.3 meters long. It would be the neotype that had longer legs than "Spinosaurus B." This would still produce an animal that had small legs. Also, the sail is incorrect. Hartman thinks the structure of the sail in unknown ("The Road to Spinosaurus IV: Not Your Father's JP3 Spinosaurus: 6"), but based on the skeletal information from the holotype and neotype, it wouldn't be a perfect half-circle. Spinosaurus' sail would have been similar to a sailfish's. 

Nothing against Hartman, or Witton for that matter, but I think some personal biases is being used here to produce a Spinosaurus that they think should have existed. However, the evidence is pointing in another direction. Spinosaurus is not a typical bipedal theropod dinosaur that lived on land. Once again, in the future, if evidence is presented that Spinosaurus was indeed a bipedal animal, then I will take back my belly-sliding posture. However, belly-sliding like a gharial, loon, and even a penguin, seems to be the best terrestrial form of locomotion for Spinosaurus within its swampy environment. Longer legs would get Spinosaurus stuck in the mud, exposing it to any enemies who are looking for a meal, like Carcharodontosaurus and Bahariasaurus (maybe a large crocodyliform?). Belly-sliding in the mud would help Spinosaurus to transverse easier through the swamp, while the other two theropods would have more trouble keeping up with their longer legs. Duane Nash already explained this half a decade ago. 

But I digress. Aside from laying eggs, let's not forget that this animal would have spent all of its time in the water (Beevor et al., 2020), so terrestrial locomotion would have been basically nonessential. 

Update (1/26-3/5/21): Hone and Holtz (2021) wrote a paper on Spinosaurus. They refuted the papers published by Ibrahim et al. in 2020, and put Spinosaurus was a wader, hunting for fish, and even swimming, but not an aquatic predator ("Abstract," "Summary" p. 6). They used a model for Spinosaurus that was bipedal (Figure 1), said that Spinosaurus' skull was closer to terrestrial animals (despite saying that Spinosaurus' skull is in between terrestrial and fully aquatic animals) ("Results: Skull Shape" p. 3) (Figure 3), questioned Spinosaurus' tail as being adapted for underwater propulsion ("Results: Tail"), questioned Spinosaurus' feet as being designed for swimming ("Results: Ungual Shape" and "Hind limbs"), said that Spinosaurus would have had trouble chasing after prey and keeping itself buoyant in the water ("Results: Aquatic Locomotion" p. 13) (Laura Geggel, 2021, p. 8), that Spinosaurus' sail might be a display feature ("Results: Dorsal and Caudal Sail Function" p. 7), and that Spinosaurus was a terrestrial and aquatic hunter, not just an aquatic one ("Results: Environmental Factors" p. 5). 

Hone's and Holtz's Spinosaurus Neotype Design by Genya Masukawa (Figure 1):
Figure 1: Spinosaurus wading  design (Top) (standing in water with head above the waves) is said to be more accurate than the swimming design proposed by Ibrahim et al., (2020)(b) (Bottom). Black arrows represent disproven traits. Gray arrows represent traits that can go with, or against, either model. White arrows represent traits that can go with either model. Scale bar is 1 meter:
Figure 1 Description:
Judging from the Figure 1 diagram, Spinosaurus' legs and tail might've been able to help it swim, but according to Hone and Holtz, the animal seems to thrive better as a wader, not a swimmer. Nizar Ibrahim says that Hone and Holtz's paper doesn't change anything (Laura Geggel, 2021, p. 17).

There are a few problems that I've found with Hone's and Holtz's paper: 

1. They did state that the design of Spinosaurus' skull is in between terrestrial and fully aquatic but they chose to say it was more likely a terrestrial-like theropod skull.

2. They used a Spinosaurus model that had longer legs and not a "M"-shaped sail. 

3. They questioned Spinosaurus' legs as being adapted for aquatic locomotion, despite being similar to a crocodilian's or a penguin's. 

As for that last part, Nash said that Spinosaurus would have been an underwater walker, and the data from Hone's and Holtz's paper actually support this view as well. This would help Spinosaurus to save more energy, and keep itself balanced, while swimming. As for the tail, if it didn't help Spinosaurus to swim, then it would have helped it to keep its balance as it walked under the water. This is similar to an average theropod's tail as they walked on land. As for the sail, Spinosaurus' sail is similar to a sail fish's, so having the sail just for display doesn't really seem complete. Spinosaurus hunting both terrestrial and aquatic prey doesn't sound so bad, although trying to figure out how it did so on land would take some time. My best guess that Spinosaurus belly-slid onto land, lied down, and waited for a small terrestrial creature to come its way. Hone's and Holtz's Spinosaurus model shows that it could walk as a biped just fine, despite evidence presented by Ibrahim et al., 2020(b) (with a COM greater than the femur length). That is still problematic. Most Spinosaurus teeth are found in ancient aquatic environments where other terrestrial animals are very rare, or even absent. This doesn't sound like an animal that would spend most of its time near land. Maybe Spinosaurus ambushed some terrestrial prey from time to time, but it would have to be in the water. There's also a problem with the fact that Spinosaurus' skull wasn't designed to hunt giant prey. Perhaps Spinosaurus hunted pterosaurs, as Hone and Holtz (2021) hinted at ("Results: Environmental Factors" p. 2). However, Spinosaurus couldn't run on land, therefore it would have to be from the water, or as I've explained above, it would slide onto land, and then lie and wait for a small creature to appear. The design of Spinosaurus' body also doesn't make it friendly towards land. The dense bones also seem to be odd on an animal that would have spent time on land, while most other theropod dinosaurs have hollow bones. Hone and Holtz say that Spinosaurus would have been in competition with both land and aquatic predators ("Results: Environmental Factors" p. 5), but it would be easier for Spinosaurus to take on a giant crocodyliform in the water than a Carcharodontosaurus on land, among other terrestrial carnivorous theropods. (Also, even though Hone and Holtz state that Spinosaurus was a weird theropod that preferred aquatic environments, you can bet that more people will take this paper as saying that Spinosaurus was an average terrestrial theropod)

Hone and Holtz wrote a very detailed paper, summarizing all the previous studies on Spinosaurus and its kin. Since Dr. Holtz is my professor now, I want to be careful with what I say. However, as I've heard him say many times now, science is about being objective. Taking this into account, I do not think that this paper gets rid of a possible aquatic Spinosaurus, but I do think Hone and Holtz make some good points that definitely fits with Nash's underwater-walking Spinosaurus. If Spinosaurus didn't swim after prey, then walking in the water and stalking prey would be the next best bet. However, I don't think that Spinosaurus just being a wader works, especially with the massive amount of Spinosaurus teeth discovered with other fish fossils in an ancient riverbed. Evidence in the future might change this and put Spinosaurus as a terrestrial predator again, but as of right now, Spinosaurus still seems to be more at home in the water. 

As I've said before, Hone's and Holtz's paper fits well with Nash's portrayal of Spinosaurus, so an underwater-walking Spinosaurus is the best bet for now. I am more open to Spinosaurus being bipedal and more terrestrial now, but the weight of the evidence (as far as I can tell) points to a dinosaur that spent most of its time in water and wasn't suited well for terrestrial habitation. 

Update (2/13/21): Spinosaurus is not the first carnivorous dinosaur to be at home in the water. The hesperornithiformes were an order (Martin et al., 2012, 2. Systematic paleontology) of theropod dinosaurs that looked a lot like modern birds (UCMP, Introduction to the Hesperornithithiformes p. 4). They also spent most of their time in the water. What's more important to me is that they couldn't walk as bipeds on land. They belly-slided (Martin et al., 2012, 1. Introduction para. 2) (Martynuik, 2012, p. 170). Since their hind limbs were designed for swimming, they couldn't travel on land well. Some genera might have been capable of flight, but most hesperornithiformes swam to travel instead of walked (Bell et al., 2019, p. 10: 4.1. Ecological implications para. 2) (Martin et al., 2012, 1. Introduction para. 2, 3. Discussion para. 3). 

It seems that the more specialized an animal is for a semi-, or fully, aquatic lifestyle, their hind limbs don't function well on land anymore. If people can't, or even refuse, to see that this is what's happening for Spinosaurus, then how can the hesperornithiformes get away with this? We already have theropods that couldn't walk as bipeds anymore because they were specialized swimmers. As diverse as dinosaurs were, just accepting that one family of theropods could forgo bipedal locomotion on land for swimming and not another is narrowing our view of how these creatures looked and lived. Like I said before, if it's proven that Spinosaurus was capable of bipedal locomotion, then I'll recant my position on this whole matter. However, the physiology of Spinosaurus seems to point to belly-sliding, especially since another family of theropods have taken this route.

In summation, Spinosaurus is closer to the gharial, loon, and hesperornithiformes, in terms of terrestrial locomotion, not other terrestrial theropods. Spinosaurus was a belly-slider, not a biped.

Update (2/15/21): Larramendi et al., (2020) addressed Henderson (2018) in their paper from 2020, and stated the problems that helped Henderson to get his results. They say that, if the remodel of Spinosaurus with its paddle-like tail is correct, had a wider torso/thoracic region that it would have had in real life, and modified the air sacs, then Spinosaurus would have been more stable in the water than suggested by Henderson. They also give Spinosaurus, and other spinosaurs, an NSG (specific gravity/density/weight of an animal or object; see Abstract) of 1.05, compared to Henderson's SG of 0.833 (3. Results and Analysis 3.2.9 Nonavian avepod theropod dinosaurs, para. 2-3). The buoyancy of water is 1.0 SG (2 Methodological Considerations: 2.1 Water and air). This means that Spinosaurus would sink below the water.

Quote from Larramendi et al., (2020) on Henderson (2018) (3. Results and Analysis 3.2.9 Nonavian avepod theropod dinosaurs para. 3):
Larramendi et al. also state that, in Larramendi's and Paul's unpublished observations, Spinosaurus' "terrestrial performance" would have been "limited," due to its "small ilium and hindlimb proportions relatively to its large BM (body mass)." This helps to support the "too short femur relative to its center of mass for a feasible terrestrial bipedal locomotion on land." They also state that isotopes collected by Amiot et al., (2011) help to support this as well (3. Results and Analysis 3.2.9 Nonavian avepod theropod dinosaurs para. 2):
Once again, this shows that Spinosaurus was not a typical terrestrial bipedal theropod. This also seems to support the idea of Spinosaurus being a competent swimmer. Even if it wasn't able to pursue after prey underwater, a Spinosaurus walking as a biped in the water is the best bet, as stated by Nash and still supported by the findings of Hone and Holtz (2021). It would stand still in the water, waiting for anything to come close to it, and when the time came to strike, it did. On land, however, it would be a belly-slider, similar to hesperornithiformes, gharials, and loons. The best way for it to hunt on land would be to lie and wait. When a small animal (more likely a pterosaur) unconsciously walks past a hiding Spinosaurus, the dinosaur would attack!  

Update (3/28/21): Hummingbirds can't walk or hop, since their legs are small and not very strong. They can shuffle, but that seems to be it (Hummingbird Central, "Hummingbird  Facts and Family Introduction: Flying ... and Walking," para. 2). 

It looks like Hummingbirds were designed mainly for flying rather than for walking. The same can probably be said for Spinosaurus, which swam, or walked, in water rather than walked on land. 

Update (8/28/21): Gimsa and Gimsa (2021) wrote a paper that tries to give some leeway on the hypothesis that Spinosaurus was a underwater pursuit predator. Here's some notes that I've taken while reading their paper:

1. Introduction, para. 5: Spinosaurus' sail is shaped like a sailfish's. 
2. Introduction, para. 6: Spinosaurus' skull, and neck, designs allowed it to "pivot feed," which is using fast head movements to capture prey underwater.
3. Discussion: Buoyancy and Balance Aspects, para. 2: Straight neck in water moves COM towards belly, while an "S-shaped" neck moves COM closer to the hips and allows for bipedal locomotion on land.
4. Conclusions: Authors think that the question arises if Spinosaurus was actually semi-terrestrial. 

Note four is very interesting to me. Spinosaurus always seemed like it would have been at home in the water rather than on land. However, note three sounds like a good compromise for the whole debate about Spinosaurus' terrestrial lifestyle. At this point, I really don't care if Spinosaurus was a belly-slider, or bipedal.

Update (6/19-22/22): Sereno et al., (2022) have concluded that Spinosaurus was bipedal, wasn't an aquatic dinosaur, and hunted along the shores (Abstract, Conclusions, 2, 4, 6-8, 11). The center of mass was about 13.2-28.5 cm. The femur was longer than that (about 40 cm) (Materials and Methods, Flesh model density, dimensions and properties, para. 4).

Spinosaurus' posture (Sereno et al., 2022, Figure 1, A-E):
Spinosaurus' center of mass (Sereno et al., 2022, Figure 2). Red plus sign is the CoM:
Abstract:
Center of Mass (CoM) ((Materials and Methods, Flesh model density, dimensions and properties, para. 4):
However, Fabbri et al., (2022) continued to use Ibrahim et al., (2020b)'s design for Spinosaurus (Figure 1). They also studied the thickness of the cavity of the bones, and found that they were almost solid inside. This means that Spinosaurus was a water-loving dinosaur and dived for food. Baryonyx was about the same, while Suchomimus was more terrestrial (pp. 854 and 856; Figure 3). The occupation of spongiosa in the medullary cavity is also present in quadrupedal animals like sauropods, ornithischians, and large-bodied terrestrial mammals (Figure 1).

Spinosaurus' design and spinosaur bone density (Fabbri et al., 2022, p. 854, Figure 1):
So now, we have two different papers on Spinosaurus this year with two different outcomes. Perhaps Spinosaurus was more terrestrial, or maybe it was still semi-, or even fully-, aquatic. What I do know is that, based on the bone density from Fabbri et al., (2022), Spinosaurus couldn't just be dipping its toes into the water and then staying a fully-terrestrial dinosaur. As was mentioned in Larramindi et al., (2020) as well, Spinosaurus' thick bones fit more with a theropod that liked to swim and would be heavier than the gravity of water. Given the larger SG provided in Larramindi et al., (2020), I think the thick bones and SG of Spinosaurus would have made it capable of submerging in water.  

Caneer et al., (2021) found T. rex arm marks in Colorado that suggests that it rose from a quadrupedal stance into a bipedal one (Abstract; pp. 29-30; p. 33 Figure 6, C; p. 35 Figure 8). If T. rex could use its arms like that, then I believe that Spinosaurus using its (longer) arms to help pull its body forward on the ground in a belly-sliding posture would have worked.

T. rex arm trace fossils (Caneer et al., 2021, p. 33 Figure 6, C):
Drawing of T. rex showing how it used its arms to sit down, or even get up from the ground (p. 35 Figure 8):
I believe that this helps to support my belly-sliding idea for Spinosaurus. 

Update (3/11-8/24/24):
I've come to the conclusion that Spinosaurus was quadrupedal, and that it pronated its hands, or did something similar, while walking on land. The humerus-to-femur ration is between 81.1-92.6% (for the neotype). I also got a CoM of 1.02-3.43 m for the neotype (1.02 m, 1.201 m, 2.33 m, and 3.43 m, are the best estimates). See my recent post to find out more:
Spinosaurus hunted mainly fish. It would go into the water and catch fish while swimming (Ibrahim et al., 2020, "Abstract") (Jackson Ryan, 2020) (Will Dunham, 2020).

Spinosaurus Hunting Bawitius:
The fish that Spinosaurus hunted were pretty big, like Mawsonia (3.5-6.3 meters) (Dutel et al., 2014, pg. 1241) and Onchipristis (5-6 meters) (David Moscato, 2017).

Onchopristis from Planet Dinosaur:
Onchopristis' Size (David Moscato, 2017):
Spinosaurus and Prey (Jamale Ijouiher, 2016, Figure 8):
However, Spinosaurus might not have hunted the large adults. It might have gone after the young, or smaller fish, that it could swallow. According to Charlie Underwood, as stated in the article This Huge Ancient Sawfish Had Harpoons On Its Face by David Moscato, says that Spinosaurus "had crocodile-like teeth and so could not cut food and would have largely been limited to fish it could swallow whole" (10). On the other hand, an Onchopristis skeleton with a Spinosaurus tooth in it. The fish got away. It looks like the fish was too strong for Spinosaurus' jaws and it broke free. ("Palaeobiological Significance," under the "Discussion" section in Spinosaur taxonomy and evolution of craniodental features: Evidence from Brazil, p. 5). Spinosaurus might have hunted small fish mainly since they were easier to catch and eat, but it does seem like Spinosaurus hunted larger fish as well. Other prey might have included small sharks like Cretolamna appendiculata, Squalicorax baharijensis, and possibly other smaller aquatic or marine animals like polycotylidae and turtles (Ijouiher, 2016, Figure 8).

In the scientific paper Spinosaur taxonomy and evolution of craniodental features: Evidence from Brazil, by Sales and Schultz (2017), it was revealed that Spinosaurus used its vision and mechanoreceptors (sensory organ) to spot and sense for prey, rather than using olfaction (sense of smell). This was perfect for catching fish and other aquatic prey, so it's more than likely now that Spinosaurus hunted mainly in the water rather than on land. The holes on the tip of Spinosaurus' snout were used for mechanoreception. It was also stated that other spinosaurids that used olfactory for hunting, like Irritator and Suchomimus for example, were more terrestrial than those who did not use olfactory, like Spinosaurus. Therefore, Spinosaurus not only hunted marine prey most of the time, but mainly spent its time in the water as well ("Palaeobiological Significance," under the "Discussion," p. 4-5). Also, due to the different hind limb bone sizes, it was mentioned that Spinosaurus was more aquatic than Suchomimus, for example, since it had shorter back legs ("Palaeobiological Significance," under the "Discussion" section, p. 2).

Hone and Holtz, Jr. (2017) stated that spinosaurids had teeth with few serrations, so tearing apart prey would not have been likely (pg. 1127). It seems that they might have swallowed their prey whole, as stated before (Moscato, 2017). They also stated that the spinosauridae seem to have used their hands for digging or even perhaps for intimidation, rather than catching and dissecting prey (pg. 1128-1129; Figure 6). They might not have even been scavengers, especially given how many spinosaur species coexist in some areas (pg. 1127). They also suggested that the spinosauridae could swallow large prey (pg. 1128-1129).

Arden et al., (2018) stated that Spinosaurus' eyes sat on the top of its head, similar to crocs and hippos ("Abstract"), while the rest of its body was submerged in water. The paper Spinosaur taxonomy and evolution of craniodental features: Evidence from Brazil, says that Spinosaurus hunted using mechanoreception, or sensors on its snout, to hunt, and this was used mostly to hunt aquatic prey ("Discussion").

Supposedly, Spinosaurus couldn't swim after prey, as stated in The Atlantic's 2016 article and Henderson's 2018 paper. Henderson (2018) says that Spinosaurus would flip over if Spinosaurus couldn't touch the bottom of the water with its feet, no matter how much it inflated its lungs. Spinosaurus would have had to walk along the shore and catch its food that way, or go in shallow water and catch food or else it would drown. However, as stated before, Gimsa et al., (2016) explained that Spinosaurus could have used its sail to stay underneath the water, and it would give more power to its neck and tail. This would have helped Spinosaurus to catch aquatic prey ("Abstract," "Introduction," Figure 1). Therefore, using its sail and tail, Spinosaurus would have hunted fish while submerged in the water.

To sum this all up, Spinosaurus spent most of its time near or in the water (either at the water's edge, in shallow water, or even in semi-deep water) and hunted fish and other marine life. It could have used its eyes, neck, sail and tail to catch fish while in the water while its nose sat above the water. It seems that it would only catch prey that it could swallow whole with its jaws. As for its claws, they seem to have been used for digging after prey in the ground or for making nests.

 Update (4/29/30): Spinosaurus could swim in water now, thanks to the fin on its tail (Ibrahim et al., 2020) (Jackson Ryan, 2020) (Will Dunham, 2020). Therefore, it would hunt for food while in the water. It probably hunted by using its jaws mainly (Hone and Holtz, Jr., 2017, pg. 1127-1129), but perhaps the claws also played a part (Jason Treat and Mesa Schumacher, 2020). This would be tricky, since theropods could only place their palms medially (side to side) to each other (Milner et al., 2009, "Abstract: Conclusions/Significance") (Eliza Strickland, 2009) (Thomas H. Maugh II, 2009), and theropods could only grab prey that was at the base of their necks and under their chests (Senter and Robins, 2005, "Abstract") ("Senter and Sullivan, 2019, "Functional and Behavioral Inferences"). It seems more plausible for Spinosaurus to use its jaws most of the time. It might have only used land to rest or lay eggs.

There's still a question of how deep could Spinosaurus swim? Swimming in deep water might have been prohibited, due to the animal's COM, as explained by Sereno when he and his team did a test (The Atlantic, 2016, p. 15), but Spinosaurus definitely seems to have been a river monster (Gramling, 2020, p. 3) (Dunham, 2020, p. 1 and 3). It probably didn't swim too fast in the water, given it's size, as explained by Lauder. Pierce says that the animal seems to have swam "about two-and-a-half meters per second," based on the neotype specimen (Simon, 2020, p. 12). Duane Nash (March 9, 2016) says that Spinosaurus used the rivers to walk, and its tail would have helped. He also says that Spinosaurus' thick bones would have sunk the animal deeper into the water. With its short legs and thick bones, Nash says that Spinosaurus would have swam/walked in the water similarly to a hippo, which also has thick bones and short limbs. Ibrahim et al., (2020) (Tail-propelled aquatic locomotion in a theropod dinosaur) says that Spinosaurus lived in a freshwater environment (pg. 3), and its teeth have been found in an ancient riverbed (Carly Cassella, 2020, p. 1) (Sci News, 2020) (Alex Fox, 2020, p. 2). Based on all of this information, it seems to me that Spinosaurus swam in shallow rivers, and would have used them to walk or swim. Perhaps deeper water wouldn't have been good, due to its COM and thick bones. I think Spinosaurus would have lived in a freshwater marsh, which are common near rivers and are "usually one to six feet deep" (NHPBS, "Freshwater Marshes" p. 1). The Everglades is one of them (Forest Preserve District of Will County, 6/11/20, "What's the Difference?: Wetland vs. Marsh vs. Swamp" p. 9-10). It's about 4-9 feet deep (Everglades Holiday Park, "5 Things You Might Not Know About the Florida Everglades: The Everglades is shallow"). That sounds about right, considering that sawfish (Onchopristis is one of them) are found mainly in shallow water (NWF, "Sawfish: Range" p. 2). This water can be less than 1, but up to 3, meters deep. They can be found in water "over 70 meters deep" though (Australian Government Department of Agriculture, Water and the Environment, "Pristis zijsron-Green Sawfish, Dindagubba, Narrowsnout Sawfish: Habitat" p. 1-4). Perhaps Spinosaurus could go into slightly deeper water, but not too much. I would say maybe just enough to submerge its sail. I believe that larger specimens of Onchopristis might be there too.

Update (9/30/20): With a high record of Spinosaurus teeth recorded by Beevor et al., (2020), it seems that Spinosaurus possibly spent all of its time in the rivers of prehistoric Africa (as well as South America). This means that this dinosaur was possibly aquatic altogether (Beevor et al., 2020, "Abstract," Table 1A-B, "Discussion: Relative Abundances," "Conclusions") (Sci News, 2020, p. 15) (Carly Cassella, 2020, p. 8 and 13) (Alex Fox, 2020, p. 2). Of course, I would say that egg-laying would have been the only thing that made Spinosaurus go onto land, and belly-sliding would have helped with that.

Update (10/27-30/20): Gharials also live in freshwater rivers (Animal Diversity Web, "Gavialis gangeticus Gharial," "Habitat"). 

Update (2/13/21): Hesperornithiformes swam in freshwater ((Martin et al., 2012, 1. Introduction para. 2, 3. Discussion para. 3).

Spinosaurus' habitat consisted of mangrove swamps (Ijouiher, 2016, pg. 2-3 “Lithrostratigraphy” p. 2; “Paleoenvironment: Topography” p. 1; pg. 4 Figure 2). Once again, the Everglades is a mangrove swamp (United states Environmental Protection Agency, "Wetlands: Mangrove Swamps," "Description"). I think we can assume, at this point, that Spinosaurus lived in an Everglades-like environment with waters reaching up to nine feet deep. Interestingly, the climate seem to have consisted of monsoons and storms, and forest fires (Ijouiher, 2016, pg. 4 “Climate”). Spinosaurus' environment wasn't exactly peaceful.

Update (4/18/21): A couple of weeks ago, I asked professor Holtz how Spinosaurus would have hunted for food. He said exactly what I had hypothesized for a while now: Spinosaurus used its jaws to shake its prey apart, and then swallow down the pieces. It's claws would not have helped it in hunting. 

There's a good reason why Spinosaurus didn't use it's hands to help it hunt: They were shrinking! Professor Holtz told me about some new Spinosaurus arm bones that were discovered recently. Apparently, the lower arm (radius and ulna) are very reduced, and the third finger is really long. Professor said that Spinosaurus' arms were shrinking, akin to what the tyrannosaurids and carcharodontosaurids were doing with their arms! This is why Spinosaurus relied more on its jaws for catching food instead of its hands and claws.

As I've also observed, the claws on the hand are smaller, and thinner, than other spinosaurids. Both Baryonyx species (or Baryonyx and Suchomimus, if you consider the two genera to be separate) have a large thumb claw on their first fingers that is really thick. Spinosaurus doesn't have this.

Spinosaurus arm from DinoLab's Instagram page (Gramho):

Here's another picture of the hand compared to a full-grown woman for scale (The Zone @91-3, 9/2/20):
Perhaps these elongated fingers help to back up Luis V. Rey's hypothesis of a "walrus-like" posture for Spinosaurus on land? Well, I actually got in contact with Luis V. Rey, and we talked about the Spinosaurus arm. He said that some of the arm bones (like the wrists) are still unknown, but there is more evidence yet to be published that points to Spinosaurus being FULLY aquatic!

Here's a pic of our conversation:
It seems that Spinosaurus has more surprises in store for us yet!

Update (4/23/21): The arm is basically a composite. More information coming in the future. 

Update (6/12/21):
According to Paleontologist Roberto Diaz Sibaja, also known as Palaeos, says that the arm is a composite. The only bones that seem to be real, according to what DinoLab have said, are the metacarpals, phalanges, and the radius and ulna but they are partially complete. The humerus is totally fake. There is also some criticism towards the third finger being way too long, but it's not conclusive.

All in all, the arm is not totally trustworthy. Perhaps the metacarpals and phalanges are real, along with the partial radius and ulna, but I would take this with a grain of salt. 

Here's everything that Mr. Sibaja said on his FaceBook post:
Update (8/28/21):
Gima and Gimsa (2021) hypothesize that Spinosaurus' skull, and neck, designs allowed it to "pivot feed," which is using fast head movements to capture prey underwater (Introduction, para. 6). 

Update (6/19-22/22): Sereno et al., (2022) said that Spinosaurus was a bipedal, semi-aquatic, piscivorous theropod that didn't hunt in water but from the shore. It weighed about 7, 400 kg, with an average density of 830 kg/m^3. This is lighter than water at 1,026 kg/m^3. This means that Spinosaurus could float, but not dive. It could stand in water that was 2.6 meters high (Abstract; Conclusions, 2-8, 11).

Conclusions, 2-8:
Conclusions, 11:
On the flip side, Fabbri et al., (2022) said that Spinosaurus' body design, including extremely thick bones, allowed for it to have an aquatic lifestyle (pp. 852, 854, 856-857; Figures 1 and 3). This is similar to the larger SG obtained by Larramidi et al., (2020). 

In conclusion, it's up to the reader to decide what kind of lifestyle Spinosaurus had. I'm tired of flip-flopping with this animal, and it's time that I came to my own conclusions based on the evidence. Since I am no stranger to taking a more controversial route, I am going to stick with Spinosaurus being a semi-, or fully-, aquatic animal, based on the dense bones, the higher SG, and the small leg and hip bones. It wouldn't make sense for a strictly terrestrial theropod to have a body plan similar to other semi- and fully-aquatic animals if it wasn't going into the water most of the time. I believe that Spinosaurus mostly stayed in the water and hunted there, or even ambushed small prey on land sometimes. I believe that it was still a belly-slider due to its smaller legs than its other relatives like Baryonyx, and would have better luck standing up as a biped in water.

Jaw Strength:
Spinosaurus' jaws were elongated and thin. According to Cuff and Rayfield (2013), authors of the article, Feeding Mechanics in Spinosaurid Theropods and Extant Crocodilians, it's jaws had a high resistance to bending and torsion compared to some crocodilians, but it doesn't have a strong resistance to mediolateral and dorsoventral bending. It's resistance to torsion is similar to that of a gharial. Thus, Spinosaurus would have preferred small prey ("Discussion" p. 6-8 and "Conclusion"). However, the article also says that what the animal ate depended on its body size. Therefore, since Spinosaurus was so big, it could have eaten some large animals, but it would have to do so without too much torsion and bending to its jaws ("Abstract" par. 2).

I think Spinosaurus would have definitely swallowed down smaller fish. When it comes to larger fish (Onchopristis and Mawsonia), there's a bit of a conundrum. Spinosaurus could have shaken large fish until they broke up into smaller pieces, but hopefully this wouldn't do damage to its skull. I think Spinosaurus would have carefully torn off pieces of a larger fish, like a fin or the tail, and then swallow them down systematically. This is just a guess of mine, but I think it is a highly probable scenario.

Contemporaries:
In Africa, Spinosaurus lived alongside Carcharodontosaurus, Bahariasaurus, the abelisaurid OLPH 025, Paralititan, Rebbachisaurus, various crocodyliforms, and Ouranosaurus or a new species of ornithopod. Only a tooth, and a giant footprint, from an ornithopod have been found. Most of Spinosaurus' African counterparts are explained in the article Paleontological studies of Cretaceous vertebrate fossil beds in the Tataouine Basin (southern Tunisia) by Michela Contessa in 2013 (All: Pages 20-29; Sarcosuchus: Pages 25-26, 28; Spinosaurus, Carcharodontosaurus, and ornithopod: Pages 27-29). Ibrahim et al., (2020) discusses the ornithopod fossils as well ("Dinosauria," "Ornithischia"). As if the weather wasn't bad enough (Ijouiher, 2016, pg. 4 “Climate”).

In South America, Spinosaurus lived alongside Argentinosaurus, Patagotitan, MMCH-Pv 47, Andesaurus, Limaysaurus, Cathartesaura, Anabisetia, Giganotosaurus, Ekrixinatosaurus, Skorpiovenator, Buitreraptor, Unenlagia, and Gualicho.

However, when it comes to interacting with the other carnivorous dinosaurs, Spinosaurus spent most of its time in the water, away from the other carnivores (Kristen Rogers, 2020, "Competing for food," p. 1).

Links:
Ernst Stromer (1915):
Translated to English:
http://www.dinochecker.com/papers/Stromers-Egypt-expedition_Spinosaurus_Stromer_1915.pdf
Original (Article 3):
https://www.biodiversitylibrary.org/item/124817#page/126/mode/1up
Stromer (1936) (Pg. 65): 

https://www.zobodat.at/pdf/Abhandlungen-Akademie-Bayern_NF_33_0001-0102.pdf

Website:
https://www.zobodat.at/publikation_series.php?as_l%5B0%5D%5Bi%5D=surnamenr&as_l%5B0%5D%5Bqt%5D=equals&as_l%5B0%5D%5Bv%5D=66775&as_l%5B1%5D%5Bi%5D=&view=list

Time:
Albian-Cenomanian:
Candiero et al., (2018) (Table 1):
https://pubs.geoscienceworld.org/sgf/bsgf/article/189/4-6/15/565723/large-sized-theropod-spinosaurus-an-important
Link 2:
https://www.researchgate.net/publication/328358895_Large-sized_theropod_Spinosaurus_an_important_component_of_the_carnivorous_dinosaur_fauna_in_southern_continents_during_the_Cretaceous
Link 3:
https://www.semanticscholar.org/paper/Large-sized-theropod-Spinosaurus%3A-an-important-of-Candeiro-Gil/9dfd67b8cadea47eb179bc423ecd8ab97134e231
Albian:
A.F. de Apparent (1960) ("Age of Continental Intercalaire," p. 11):
https://paleoglot.org/files/Lapparent_60.pdf
Taquet and Russell (1998) (Pg. 351, "Conclusion"):
Buffetaut and Ouaja (2002) (Pg. 415-416):
https://core.ac.uk/download/pdf/15484814.pdf
Link 2:
https://core.ac.uk/reader/15484814
Contessa, Michela. Paleontological studies of Cretaceous vertebrate fossil beds in the Tataouine Basin (southern Tunisia). 2013. Pg. 20-29:
http://amsdottorato.unibo.it/5240/1/Contessi_Michela_tesi.pdf
Beevor et al., (2020) ("Geological context" p. 3):

https://www.sciencedirect.com/science/article/pii/S019566712030313X

Cenomanian:
Ernst Stromer (1915) (Pg. 1):
http://www.dinochecker.com/papers/Stromers-Egypt-expedition_Spinosaurus_Stromer_1915.pdf
Ibrahim et al., (2014) (Pg. 1613):
https://www.researchgate.net/publication/265553416_Semiaquatic_adaptations_in_a_giant_predatory_dinosaur
Supplementary Materials (Pg. 18, "Stratigraphic Position"):
http://science.sciencemag.org/content/suppl/2014/09/10/science.1258750.DC1/Ibrahim.SM.pdf
Ibrahim et al., (2020). Geology and paleontology of the Upper Cretaceous Kem Kem Group of eastern Morocco. ("Age," p. 2, 4-6):
https://zookeys.pensoft.net/article/47517/element/7/0/deltadromeus/
Beevor et al., (2020) ("Geological context" p. 3):

https://www.sciencedirect.com/science/article/pii/S019566712030313X

International Chronostratigraphic Chart (2020):
https://stratigraphy.org/timescale/
International Commission of Stratigraphy Website:
https://stratigraphy.org/news/130
Size:
https://psdinosaurs.blogspot.com/2018/12/spinosaurus-specimens_19.html
Link 2:
https://psdinosaurs.blogspot.com/2018/10/calculations-for-largest-theropods.html
Dal Sasso et al., (2005) (Pg. 895):
Therrien and Henderson (2007) (pg. 111): 
https://docs.google.com/viewer?a=v&pid=sites&srcid=ZGVmYXVsdGRvbWFpbnxiYXJ5b255eHBkeHxneDo0MmEyZjA2MWEzM2Q1Mjhj
Ibrahim et al., (2014) (Pg. 1613):
Supplementary Materials (Pg. 9):
Paul Sereno ("Spinosaurus aegyptiacus"):
Henderson, Donald M. (2018) ("Materials and Methods," p. 1):
Arden et al., (2018) ("Phylogenetic Analysis," p. 4-5):
https://www.researchgate.net/publication/326507888_Aquatic_adaptation_in_the_skull_of_carnivorous_dinosaurs_Theropoda_Spinosauridae_and_the_evolution_of_aquatic_habits_in_spinosaurus
Lakin and Longrich (2018) (Pg. 139):
Ibrahim et al., (2020a). Geology and paleontology of the Upper Cretaceous Kem Kem Group of eastern Morocco. ("Taphonomy," "Spinosauridae"):
https://zookeys.pensoft.net/article/47517/element/7/0/deltadromeus/
ScienceDaily (2020):
https://www.sciencedaily.com/releases/2020/04/200423130449.htm

Sereno et al., (2022):

https://www.biorxiv.org/content/10.1101/2022.05.25.493395v1.full

Oxalaia is Spinosaurus:
Smyth et al., (2020) ("Abstract"):
Time:
Kellner et al., (2010):
http://www.scielo.br/pdf/aabc/v83n1/v83n1a06.pdf
Size:
https://psdinosaurs.blogspot.com/2018/10/calculations-for-largest-theropods.html
Spent Time in Water:
Kristen Rogers (2020) ("Competing for food," p. 1):
https://www.cnn.com/2020/04/29/world/spinosaurus-swimmer-discovery-scn/index.html
Weight:
Henderson, Donald M. (2018) (Table 2):
https://peerj.com/articles/5409/
Ibrahim et al., (2020b). Tail-propelled aquatic locomotion in a theropod dinosaur:
https://www.nature.com/articles/s41586-020-2190-3.epdf?sharing_token=wElGAWkXZX3eB14Er_jbUdRgN0jAjWel9jnR3ZoTv0OcJuFkKXfvVfjOrYF9meV2qCJkOX1x2LjcUMb1Lb5lZ9chhU_Vqfej8-PBfY04xZnY48UXBKYSWhbFemIIs3mnslnJcMCkPcDsf4JmQim7ZWuw7gTuaSQgIH1NES8XsNEAQbuXpuNMgu2T0alEiU1nolCaK6s1p8TvLl3vrvhPiBE9R0sp6pL6T-Jdz-i53gDgBKDkO1M4-gD343aSCj8uA6Wk_OUCrH_JGGWbqhjD9_2bj7JSympkyTP7aZ9BtXc%3D&tracking_referrer=www.sciencenews.org
Link 2:
https://www.nature.com/articles/s41586-020-2190-3
Supplementary Information (pg. 29 "Body mass, segment masses, and centre of mass (CoM)"):
https://www.readcube.com/articles/supplement?doi=10.1038%2Fs41586-020-2190-3&index=0

Sereno et al., (2022):

https://www.biorxiv.org/content/10.1101/2022.05.25.493395v1.full

Sail:
Gimsa et al., (2016). The riddle of Spinosaurus aegyptiacus' dorsal sail:
https://pubs.geoscienceworld.org/geolmag/article/153/3/544/353182/the-riddle-of-spinosaurus-aegyptiacus-dorsal-sail
Andrew Whalen (2020) (P. 9):
https://www.newsweek.com/spinosaurus-tail-fossil-discovery-paddle-jurassic-park-aegyptiacus-size-skeleton-aquatic-1501509

Sereno et al., (2022):

https://www.biorxiv.org/content/10.1101/2022.05.25.493395v1.full

Locomotion History:
Donald F. Glut (2001) (Pg. 82 and 84):
Charig and Miller (1997) (Pg. 12 and 55):
Sereno et al., (1998) (Pg. 1300):
Scott Hartman (September 12, 2014):
Scott Hartman (September 13, 2014):
Andrea Cau (2014):
Andrea Cau (2015):
Duane Nash (August 16, 2014):
Duane Nash (September 14, 2014):
Scott Hartman (September 18, 2014):
Henderson, Donald M. (2018):
Ibrahim et al., (2020b). Tail-propelled aquatic locomotion in a theropod dinosaur:
https://www.nature.com/articles/s41586-020-2190-3.epdf?sharing_token=wElGAWkXZX3eB14Er_jbUdRgN0jAjWel9jnR3ZoTv0OcJuFkKXfvVfjOrYF9meV2qCJkOX1x2LjcUMb1Lb5lZ9chhU_Vqfej8-PBfY04xZnY48UXBKYSWhbFemIIs3mnslnJcMCkPcDsf4JmQim7ZWuw7gTuaSQgIH1NES8XsNEAQbuXpuNMgu2T0alEiU1nolCaK6s1p8TvLl3vrvhPiBE9R0sp6pL6T-Jdz-i53gDgBKDkO1M4-gD343aSCj8uA6Wk_OUCrH_JGGWbqhjD9_2bj7JSympkyTP7aZ9BtXc%3D&tracking_referrer=www.sciencenews.org
Link 2:
Supplementary Information (pg. 29, "Body mass, segment masses, and centre of mass (CoM)"):
"Body dimensions, body body mass, body segment masses, and whole body centre of mass" pg. 1:
https://www.readcube.com/articles/supplement?doi=10.1038%2Fs41586-020-2190-3&index=3
Larramendi et al., (2020):

https://anatomypubs.onlinelibrary.wiley.com/doi/abs/10.1002/ar.24574

 Otero et al., (2019):
https://www.nature.com/articles/s41598-019-44037-1
Jackson Ryan (2020):
Will Dunham (2020):
"A Swimming Dinosaur: The Tail of Spinosaurus":
Carolyn Gramling (2020):
Jason Treat and Mesa Schumacher (2020):
Image:
Article:
Mark Witton (2020) ("Spinosaurus 2020: thoughts for artists," "Posture and balance" p. 1-3):
Clea Simon (2020):
Scott Hartman (2020):
"The Road to Spinosaurus III: Of Chimeras and Leg Proportions":

https://www.skeletaldrawing.com/home/the-road-to-spinosaurus-iii-of-chimeras-and-leg-proportions11262020

"The Road to Spinosaurus IV: Not Your Father's JP3 Spinosaurus":

https://www.skeletaldrawing.com/home/road-to-spinosaurus-iv-not-your-fathers-jp3-osaurus11282020

Hone and Holtz (2021):

https://palaeo-electronica.org/content/2021/3219-the-ecology-of-spinosaurus
Gimsa and Gimsa (2021):
https://www.mdpi.com/2075-1729/11/9/889/htm
Sereno et al., (2022):

https://www.biorxiv.org/content/10.1101/2022.05.25.493395v1.full
Fabbri et al., (2022):

https://www.nature.com/articles/s41586-022-04528-0.epdf?sharing_token=rxUUwyZxDWQ24dJfwtIw89RgN0jAjWel9jnR3ZoTv0NEFj8DFZa3bazFWKdXldNTvT8T3daJQzYMUbPXaqso6c2KKBgthBeOpsV72_JOZHeSlOxZzzE9wUggHYItKT5ASyn5r0hTiRPfCQi_Cfe9RPf0tvCNFd3T4QXE2UU4r7wR-SYYL4_TSvBiBpniofeQoStgnv6yWzzkL81Gcy2g6hKT9nO8ozsufeY9DwX1VK-Vsw94pFBHTtBWnm2-q0bJ33Xx2cPSUh5t7T-nx3NDvtkT9MSkWBYPTw7aqWM5FRs%3D&tracking_referrer=www.sciencenews.org

Supplementary information:

https://static-content.springer.com/esm/art%3A10.1038%2Fs41586-022-04528-0/MediaObjects/41586_2022_4528_MOESM1_ESM.pdf

My quadrupedal Spinosaurus post:

https://psdinosaurs.blogspot.com/2023/03/what-did-spinosaurus-look-like-part-1.html

Duane Nash (August 16, 2014):
Duane Nash (September 14, 2014):
Alina Bradford (2016):
Alina Bradford (2014):
U.S. Fish and Wildlife Refuge ("Common Loons," "Nesting"):
West Pond Association ("The Common Loon," "Daily Life' p. 4):
International Penguin Conservation and Work Group ("Introduction to Penguins," p. 2):
Loon Preservation Committee ("Common Loon Plumage and Appearance," p. 1):
Wilson et al., 1991 ("Abstract"):
Gill and Prevost. "Penguin." “Natural History: Locomotion and orientation.” Encyclopaedia Britannica: 
https://www.britannica.com/animal/penguin/Natural-history

New England Aquarium. "Penguins Teacher Guide." “Physical Characteristics” pg. 2 p. 3. 2016:
https://www.neaq.org/wp-content/uploads/2016/06/LEARN_3-5-2_Penguin_TeacherGuide.pdf

Sea World Parks and Entertainment. "All About Penguins." "Physical Characteristics: “Legs and Feet” p. 3:
https://seaworld.org/animals/all-about/penguins/physical-characteristics/

Adam Britton (1995):
https://crocodilian.com/cnhc/cbd-gb4.htm
Marshall Cavendish (20011) (Pg. 60):
https://books.google.com/books?id=fU25LOYnVokC&pg=PA60&lpg=PA60&dq=belly+sliding+crocodile&source=bl&ots=f9aHV-nWCk&sig=ACfU3U0UWZhNV4cKMCrePO2wp9G2-GBfxQ&hl=en&sa=X&ved=2ahUKEwjHo8O_7YnqAhXClXIEHSdEDnMQ6AEwHHoECAIQAQ#v=onepage&q=belly%20sliding%20crocodile&f=false
Sally M. Walker (2004) (Pg. 17):
https://books.google.com/books?id=MbqS-zNASiUC&pg=PA17&lpg=PA17&dq=crocodile+belly+crawl&source=bl&ots=RHr0w9Px_C&sig=ACfU3U21x1RMKo92aeARkwdfbN6VphH8og&hl=en&sa=X&ved=2ahUKEwjlt6-W74nqAhVhg3IEHTRXDTQQ6AEwHXoECAMQAQ#v=onepage&q=crocodile%20belly%20crawl&f=false
Smithsonian National Zoo and Conservation Biology Institute. "Gharial." "Conservation." "Physical Description" (p. 3):
https://nationalzoo.si.edu/animals/gharial
Evers et al., (2015) ("'Spinosaurus B' and Sigilmassasaurus," pg. 63-67):
Link 2:
Ibrahim et al., (2020). Geology and paleontology of the Upper Cretaceous Kem Kem Group of eastern Morocco. ("Age," p. 2, 4-6):
Smithsonian National Zoo & Conservation Biology Institute. "Gharial":

https://nationalzoo.si.edu/animals/gharial#:~:text=Adult%20gharials%20primarily%20eat%20fish,at%20fish%20in%20the%20water

Animal Diversity Web. "Gavialis gangeticus Gharial" ("Habitat," "Physical Description"):

https://animaldiversity.org/accounts/Gavialis_gangeticus/
UCMP. Introduction to the Hesperornithithiformes. P. 4:
https://ucmp.berkeley.edu/diapsids/birds/hesper.html
Martin et al., (2012). 1. Introduction para. 2, 3. Discussion para. 3:
https://www.sciencedirect.com/science/article/abs/pii/S1871174X12000066
Martynuik (2012). P. 170:
https://www.google.com/books/edition/A_Field_Guide_to_Mesozoic_Birds_and_Othe/b5_DyhNk7FcC?q=Hesperornis+walk&gbpv=1&bsq=Hesperornis%20regalis#f=false
Bell et al., (2019) P. 10: 4.2 Ecological implications. Para. 2:
http://lithornis.nmsu.edu/~phoude/Bell%20et%20al%20%202018%20Morphometric%20comparison%20of%20the%20Hesperornithiformes%20and%20modern%20diving%20birds.pdf
Overland definition:
Merriam Webster. Overland:
https://www.merriam-webster.com/dictionary/overland
Larramendi et al., (2020) (3. Results and Analysis: 3.2.9 Nonavian avepod theropod dinosaurs):
https://anatomypubs.onlinelibrary.wiley.com/doi/10.1002/ar.24574

Hummingbird Central. "Hummingbird  Facts and Family Introduction: Flying ... and Walking," para. 2:
 https://www.hummingbirdcentral.com/hummingbird-facts.htm

Sereno et al., (2022):

https://www.biorxiv.org/content/10.1101/2022.05.25.493395v1.full

Fabbri et al., (2022):

https://www.nature.com/articles/s41586-022-04528-0.epdf?sharing_token=rxUUwyZxDWQ24dJfwtIw89RgN0jAjWel9jnR3ZoTv0NEFj8DFZa3bazFWKdXldNTvT8T3daJQzYMUbPXaqso6c2KKBgthBeOpsV72_JOZHeSlOxZzzE9wUggHYItKT5ASyn5r0hTiRPfCQi_Cfe9RPf0tvCNFd3T4QXE2UU4r7wR-SYYL4_TSvBiBpniofeQoStgnv6yWzzkL81Gcy2g6hKT9nO8ozsufeY9DwX1VK-Vsw94pFBHTtBWnm2-q0bJ33Xx2cPSUh5t7T-nx3NDvtkT9MSkWBYPTw7aqWM5FRs%3D&tracking_referrer=www.sciencenews.org

Supplementary information:

https://static-content.springer.com/esm/art%3A10.1038%2Fs41586-022-04528-0/MediaObjects/41586_2022_4528_MOESM1_ESM.pdf

Caneer et al., (2021):
Quadruped:
What Did Spinosaurus Look Like Part 1:Swimming and Hunting:
Ibrahim et al., (2014):
https://www.researchgate.net/publication/265553416_Semiaquatic_adaptations_in_a_giant_predatory_dinosaur
Supplementary Materials:
http://science.sciencemag.org/content/suppl/2014/09/10/science.1258750.DC1/Ibrahim.SM.pdf
The Atlantic (2016):
https://www.theatlantic.com/science/archive/2016/03/saga-of-the-spinosaurus/476286/
Henderson, Donald M. (2018):
https://peerj.com/articles/5409/
Phys (2014) (Kenneth Carpenter):
https://phys.org/news/2014-09-shark-munching-spinosaurus-first-known-dinosaur.html
Arden et al., (2018):
https://www.sciencedirect.com/science/article/pii/S0195667117303427
Sales and Schultz (2017). Spinosaur taxonomy and evolution of craniodental features: Evidence from Brazil (2017):
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0187070#sec025
Dave Hone and Thomas Holtz, Jr. (2017):
Pg. 1128:
https://www.researchgate.net/publication/318228524_A_Century_of_Spinosaurs_-_A_Review_and_Revision_of_the_Spinosauridae_with_Comments_on_Their_Ecology
Hone's Blog:
https://archosaurmusings.wordpress.com/2017/07/06/spinosaurs-in-review-sort-of/
Gimsa et al., (2016). The riddle of Spinosaurus aegyptiacus' dorsal sail:
https://pubs.geoscienceworld.org/geolmag/article/153/3/544/353182/the-riddle-of-spinosaurus-aegyptiacus-dorsal-sail
Link 2:
https://www.cambridge.org/core/journals/geological-magazine/article/riddle-of-spinosaurus-aegyptiacus-dorsal-sail/B19941405E1791A97230BCF003017B7B/core-reader
Ibrahim et al., (2020). Tail-propelled aquatic locomotion in a theropod dinosaur:
https://www.nature.com/articles/s41586-020-2190-3.epdf?sharing_token=wElGAWkXZX3eB14Er_jbUdRgN0jAjWel9jnR3ZoTv0OcJuFkKXfvVfjOrYF9meV2qCJkOX1x2LjcUMb1Lb5lZ9chhU_Vqfej8-PBfY04xZnY48UXBKYSWhbFemIIs3mnslnJcMCkPcDsf4JmQim7ZWuw7gTuaSQgIH1NES8XsNEAQbuXpuNMgu2T0alEiU1nolCaK6s1p8TvLl3vrvhPiBE9R0sp6pL6T-Jdz-i53gDgBKDkO1M4-gD343aSCj8uA6Wk_OUCrH_JGGWbqhjD9_2bj7JSympkyTP7aZ9BtXc%3D&tracking_referrer=www.sciencenews.org
Link 2:
Supplementary Information:
https://www.readcube.com/articles/supplement?doi=10.1038%2Fs41586-020-2190-3&index=0
Jason Treat and Mesa Schumacher (2020):
Image:
Article:
Milner et al., (2009) ("Abstract: Conclusions/Significance"):

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0004591

Eliza Strickland (2009): 

https://www.discovermagazine.com/planet-earth/dinosaur-handprints-show-it-could-hold-a-basketball-not-dribble

Thomas H. Maugh II (2009):

https://www.latimes.com/archives/la-xpm-2009-mar-04-sci-dinohands4-story.html
Senter and Robins (2005) ("Abstract"):

https://www.researchgate.net/publication/272152045_Range_of_motion_in_the_forelimb_of_the_theropod_dinosaur_Acrocanthosaurus_atokensis_and_implications_for_predatory_behaviour

Senter and Sullivan (2019) ("Functional and Behavioral Inferences"):

https://www.researchgate.net/publication/333636227_Forelimbs_of_the_theropod_dinosaur_Dilophosaurus_wetherilli_Range_of_motion_influence_of_paleopathology_and_soft_tissues_and_description_of_a_distal_carpal_bone

Sci News (2020):
Carly Cassella (2020) (P. 1, 8 and 13):
NHPBS. "Freshwater Marshes" (P. 1):

https://nhpbs.org/natureworks/nwep7h.htm

Forest Preserve District of Will County. "What's the Difference?: Wetland vs. Marsh vs. Swamp." 6/11/20. P. 9-10:

https://www.reconnectwithnature.org/news-events/the-buzz/what-the-difference-marsh-vs-swamp-vs-wetland

Everglades Holiday Park. "5 Things You Might Not Know About the Florida Everglades." "The Everglades is shallow":

https://www.evergladesholidaypark.com/things-you-didnt-know-about-everglades/#:~:text=The%20water%20in%20the%20Everglades,point%20is%20around%209%20feet 

Australian Government Department of Agriculture, Water and the Environment. "Pristis zijsron-Green Sawfish, Dindagubba, Narrowsnout Sawfish." "Habitat" P. 1-4:

http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=68442

NWF. "Sawfish." "Range" P. 2:

https://www.nwf.org/Educational-Resources/Wildlife-Guide/Fish/Sawfish

Animal Diversity Web. "Gavialis gangeticus Gharial" ("Habitat"):

https://animaldiversity.org/accounts/Gavialis_gangeticus/
Ijouiher (2016):

https://www.researchgate.net/publication/309508851_A_reconstruction_of_the_palaeoecology_and_environmental_dynamics_of_the_Bahariya_Formation_of_Egypt

United states Environmental Protection Agency. "Wetlands: Mangrove Swamps." "Description":

https://www.epa.gov/wetlands/mangrove-swamps
Hone and Holtz (2021):
https://palaeo-electronica.org/content/2021/3219-the-ecology-of-spinosaurus
Laura Geggel (2021) (P. 8 and 17):
https://www.google.com/amp/s/www.livescience.com/amp/spinosaurus-dinosaur-mediocre-swimmer.html
Gimsa and Gimsa (2021):
https://www.mdpi.com/2075-1729/11/9/889/htm

Sereno et al., (2022):

https://www.biorxiv.org/content/10.1101/2022.05.25.493395v1.full

Fabbri et al., (2022):

https://www.nature.com/articles/s41586-022-04528-0.epdf?sharing_token=rxUUwyZxDWQ24dJfwtIw89RgN0jAjWel9jnR3ZoTv0NEFj8DFZa3bazFWKdXldNTvT8T3daJQzYMUbPXaqso6c2KKBgthBeOpsV72_JOZHeSlOxZzzE9wUggHYItKT5ASyn5r0hTiRPfCQi_Cfe9RPf0tvCNFd3T4QXE2UU4r7wR-SYYL4_TSvBiBpniofeQoStgnv6yWzzkL81Gcy2g6hKT9nO8ozsufeY9DwX1VK-Vsw94pFBHTtBWnm2-q0bJ33Xx2cPSUh5t7T-nx3NDvtkT9MSkWBYPTw7aqWM5FRs%3D&tracking_referrer=www.sciencenews.org

Supplementary information:

https://static-content.springer.com/esm/art%3A10.1038%2Fs41586-022-04528-0/MediaObjects/41586_2022_4528_MOESM1_ESM.pdf

Spinosaurus Arm:
Holtz (pers. comm).

DinoLab:
Instagram (Gramho):
https://gramho.com/media/2535465340537444071

Facebook:

https://m.facebook.com/dinolabinc/posts/our-spinosaurus-arm-is-still-on-display-we-arent-sure-how-much-longer-we-are-goi/885524165571071/

Twitter:

https://mobile.twitter.com/DinoLab_Inc/status/1322305140020269058

The Zone @91-3:
Photo:
https://images.app.goo.gl/FYeo7rjhQr6cPLja7
Website:
https://www.thezone.fm/2020/09/02/geekout-dino-lab-spino-arm/

My Conversation with Luis V. Rey:
"The ongoing Spinosaurus Saga... now a nesting ground." 1/24/2021:

https://luisvrey.wordpress.com/2021/01/24/the-ongoing-spinosaurus-saga-now-a-nesting-ground/

Mr. Sibaja (Palaeos):
Facebook Post:

https://m.facebook.com/PalaeosPag/photos/a.157631294723661/1059058504580931
Blog:

https://palaeos-blog.blogspot.com/?m=0
Prey:
Jamale Ijouiher (2016) (Figure 8):
https://www.researchgate.net/figure/A-scale-chart-comparing-Spinosaurus-aegyptiacus-with-various-contemporaneous-taxa-S_fig4_309508851
Link 2:
https://peerj.com/preprints/2470/
Mawsonia:

Dutel et al., (2014) (Pg. 1241): 
https://www.researchgate.net/publication/265468358_A_Giant_Marine_Coelacanth_from_the_Jurassic_of_Normandy_France

Onchopristis:
Lips:
Reisz and Larson (2016) (Pg. 64-66):
https://cansvp.files.wordpress.com/2013/08/csvp-2016-abstract-book-compressed.pdf
Blake Eligh (2016):
https://www.utoronto.ca/news/did-dinosaurs-have-lips-ask-university-toronto-paleontologist
Mindy Weisberger (2016):
https://www.livescience.com/54912-did-t-rex-have-lips.html
Emanuela Grinberg (2016):
https://www.cnn.com/2016/05/22/world/dinosaur-lips-teeth-study/index.html
Phys (2016):
https://phys.org/news/2016-06-dinosaurs-lips.html
Tongue:
Mindy Weisberger (2018):
https://www.scientificamerican.com/article/t-rex-couldnt-stick-out-its-tongue/
ScienceDaily (2018):
https://www.sciencedaily.com/releases/2018/06/180620150129.htm
Jaw Strength:
Cuff and Rayfield (2013). Feeding Mechanics in Spinosaurid Theropods and Extant Crocodilians:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3665537/
Jaw Structure:
Vullo et a., (2016) ("Discussion"): 
https://www.app.pan.pl/archive/published/app61/app002842016.pdf
Tail:
Ibrahim et al., (2020). Tail-propelled aquatic locomotion in a theropod dinosaur:
https://www.nature.com/articles/s41586-020-2190-3.epdf?sharing_token=wElGAWkXZX3eB14Er_jbUdRgN0jAjWel9jnR3ZoTv0OcJuFkKXfvVfjOrYF9meV2qCJkOX1x2LjcUMb1Lb5lZ9chhU_Vqfej8-PBfY04xZnY48UXBKYSWhbFemIIs3mnslnJcMCkPcDsf4JmQim7ZWuw7gTuaSQgIH1NES8XsNEAQbuXpuNMgu2T0alEiU1nolCaK6s1p8TvLl3vrvhPiBE9R0sp6pL6T-Jdz-i53gDgBKDkO1M4-gD343aSCj8uA6Wk_OUCrH_JGGWbqhjD9_2bj7JSympkyTP7aZ9BtXc%3D&tracking_referrer=www.sciencenews.org
Link 2:
https://www.nature.com/articles/s41586-020-2190-3
Jackson Ryan (2020):
https://www.cnet.com/news/spinosaurus-fossil-discovery-rewrites-history-of-swimming-dinosaurs/
Will Dunham (2020):
https://www.investing.com/news/general/river-monster-huge-african-dinosaur-spinosaurus-thrived-in-the-water-2155334
"A Swimming Dinosaur: The Tail of Spinosaurus." "nature video." YouTube:
https://www.youtube.com/watch?v=fDhofM81RQE
Carolyn Gramling (2020):
https://www.sciencenews.org/article/spinosaurus-dinosaur-fossil-tail-aquatic-swimmer
Jason Treat and Mesa Schumacher (2020):
Image:
https://images.app.goo.gl/rVct73LcFmKNxUKJA
Article:
https://www.nationalgeographic.com/science/2020/04/spinosaurus-graphic-reconstructing-gigantic-aquatic-predator/
Clea Simon (2020):
https://news.harvard.edu/gazette/story/2020/04/new-paper-suggests-spinosaurus-may-have-been-aquatic/
Contemporaries:
Contessa, Michela. Paleontological studies of Cretaceous vertebrate fossil beds in the Tataouine Basin (southern Tunisia). 2013. (All: Pages 20-29; Sarcosuchus: Pages 25-26, 28; Spinosaurus, Carcharodontosaurus, and ornithopod: Pages 27-29):
http://amsdottorato.unibo.it/5240/1/Contessi_Michela_tesi.pdf
Ornithopods:
Fanti et al., (2016):
https://www.researchgate.net/publication/290084297_Evidence_of_iguanodontian_dinosaurs_from_the_Lower_Cretaceous_of_Tunisia
Ibrahim et al., (2020) ("Dinosauria," "Ornithischia"):
https://zookeys.pensoft.net/article/47517/element/7/0/deltadromeus/
Elosuchus:
https://psdinosaurs.blogspot.com/2020/11/size-calculations-of-crocodyliformes.html
Stomatosuchus:
https://psdinosaurs.blogspot.com/2020/11/size-calculations-of-crocodyliformes.html
OLPH 025 (Abelisaurid):
https://psdinosaurs.blogspot.com/2018/10/calculations-for-largest-theropods.html
Spinosaurus Preferred Water Instead of Land:
Kristen Rogers (2020) ("Competing for food," p. 1):
https://www.cnn.com/2020/04/29/world/spinosaurus-swimmer-discovery-scn/index.html

Fabbri et al., (2022):

https://www.nature.com/articles/s41586-022-04528-0.epdf?sharing_token=rxUUwyZxDWQ24dJfwtIw89RgN0jAjWel9jnR3ZoTv0NEFj8DFZa3bazFWKdXldNTvT8T3daJQzYMUbPXaqso6c2KKBgthBeOpsV72_JOZHeSlOxZzzE9wUggHYItKT5ASyn5r0hTiRPfCQi_Cfe9RPf0tvCNFd3T4QXE2UU4r7wR-SYYL4_TSvBiBpniofeQoStgnv6yWzzkL81Gcy2g6hKT9nO8ozsufeY9DwX1VK-Vsw94pFBHTtBWnm2-q0bJ33Xx2cPSUh5t7T-nx3NDvtkT9MSkWBYPTw7aqWM5FRs%3D&tracking_referrer=www.sciencenews.org

Supplementary information:

https://static-content.springer.com/esm/art%3A10.1038%2Fs41586-022-04528-0/MediaObjects/41586_2022_4528_MOESM1_ESM.pdf

Artwork:
David Bonadona:
http://www.davidebonadonna.it/
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