(News) A possible Spinosaurus arm has been discovered!

Yesterday after class, Professor Holtz told me about the discovery (a tricky one to say the least, but still a discovery) of a Spinosaurus arm. I had to look for it online, and a cast was made by DinoLab. 

Here's a pic from DinoLab's Instagram page (Gramho):

From what I can tell, and from what professor Holtz said to me, one of the fingers is really long for some odd reason. I think it's the third digit, based on the photo. The fingers in general are long, and I think they appear to have been flexible (well, as flexible as theropod hands could have been). The claws are actually really short for a spinosaur. Baryonyx (including Suchomimus if you want to keep the two genera separate) had huge, and robust, claws at the end of its fingers, especially on the thumb. Spinosaurus' claws are shorter and thinner.

What's even more surprising is the lower arm. The radius and ulna are really short! The humerus is long, but why are the lower arm bones barely half the length of the humerus? Well, I asked professor Holtz if it appeared that larger carnivorous theropods (like tyrannosaurids and carcharodontosaurids) grew larger heads and tossed their arms aside, and he said that it appears to be going in that route. This is so cool! Tyrannosaurids were not the only large carnivorous theropods that be going for smaller arms. It's just so surprising to see Spinosaurus going in this route because it's always been shown to have large arms. They were a composite of other spinosaurids, but it just seemed natural. Spinosaurus is a spinosaur, so naturally it would have had large arms like its relatives. Now, it appears to be the opposite. Spinosaurus' arms were not as small as T. rex's, but they have shrunk.

Interestingly, the radius and ulna are short but thick. Could this have been for support on land? Luis V. Rey suggests that Spinosaurus used its forelimbs to help it walk on land (not knuckle-walking, but actually spraying its fingers out like a walrus). Perhaps these long fingers did that? I don't know, but at this point I'm just going along for the ride. Spinosaurus is that one dinosaur now that just keeps surprising us!

I never knew that I would be so enthralled by a dinosaur that I grew up hating thanks to Jurassic Park III!

Here's another picture of the hand compared to a full-grown woman for scale (The Zone @91-3, 9/2/20):

It really is smaller than the reconstruction (Kenneth Chang, 2014):

Update: 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:

This proves that Spinosaurus is the gift that keeps on giving!

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:

Links:
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/
Kenneth Chang (2014):
https://www.nytimes.com/2014/09/12/science/a-nomads-find-helps-solve-the-mystery-of-the-spinosaurus.html
Photo:
https://images.app.goo.gl/19ScuGkueXHXFEFB9
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

Update (4/21/25-1/29/26):
I think most of this arm could be the real deal. I found a new private specimen that is a complete arm. It does resemble the DinoLab arm, so Spinosaurus' arm might've been different from other spinosaurids. Here's more information:

"I don't know how I missed this, but someone on Reddit, called Super-Masterpiece-34, posted a picture of another complete Spinosaurus arm. It's a private specimen though, but it reveals what I said about the arm from Dino Lab: The humerus would've been shorter! The third finger is also shorter than the second one, contrary to the third digit of the Dino Lab arm. The manual unguals are the same as the ones in the Dino Lab, Ibrahim et al., (2020a), and Fabbri et al., (2022), which means that Spinosaurus' manual unguals are shorter than the baryonychinae's. 

Photo of the private Spinosaurus arm (Reddit, Super-Masterpiece-34, May surprise many people):

Notice that the third finger is smaller than the first two fingers.

I don't know if this arm is more complete, or accurate, than the DinoLab arm, but it does resemble the DinoLab arm. Plus, I like the fact that the third digit is the smallest one. Second, the manual unguals match the spinosaurid manual ungual (NMC 41820) from Ibrahim et al., (2020a) (Figure 111A-B):

Full figure. Scale bar is 5 cm:

Description of NMC 41820 (Ibrahim et al., 2020a, Theropoda: Manual ungual morphotype 1):

Whatever Spinosaurus' arms were for, I don't know if they were for hunting. Perhaps they were, but I think the jaws did the hunting mostly."

Either way, part of the DinoLab arm seems realistic. The second arm seems to back this up, albeit the third digit is short. This looks more realistic.  

In total, this could very well be what Spinosaurus' arm might've looked like, aside from the elongated third digit. For more information, check out my two posts below:

Links:

What did Spinosaurus Look Like? Part 2:
https://psdinosaurs.blogspot.com/2025/04/what-did-spinnosaurus-look-like-part-2.html

Dino Bios: Spinosaurus:

https://psdinosaurs.blogspot.com/2017/09/spinosaurus-facts.html

Update (4/28/26):
I'm not sure if this is authentic or not, but I think I found another Spinosaurus arm. On an Instagram post made by dream.fossils, they said that they found a lower arm of Spinosaurus. What is interesting about the arm is that the manual digit 3, and the manual unguals, match those of the DinoLab arm. The manual unguals also match the arm from Reddit, and the manual ungual from Ibrahim et al., (2020a). 

Picture of Spinosaurus arm (dream.fossils):

We now have, possibly, two Spinosaurus arms with long third digits. If Spinosaurus had a long third finger, I wonder what the purpose for it was? How flexible was it? Could it support any weight? 

I also found a Dinopedia discussion page that said that this specimen was a real fossil (Fandom, Dinopedia, HUGE NEWS! ...As promised: Another giant 13-14 meters Spinosaurus specimen in private hands). Also, I found a video on the PNSO's Facebook profile that was uploaded in 2022. The person in the video said that, during that time, people online were hypothesizing that Spinosaurus had a long third finger that might've acted as a "fin-like structure" (Facebook, PNSO, Essien the Spinosaurus 3: The Forelimbs, 3:00). I don't remember hearing, or seeing, that idea floating around the internet back in 2022! Could Spinosaurus' hand acted like a fin, better yet a flipper? Where the hands webbed? More questions that need to be answered!

If, and I do mean if, this specimen is authentic, then this adds extra weight to the hypothesis that Spinosaurus had different hands compared to other spinosaurids. I hope Ibrahim, and his team, excavate the arms of the Spinosaurus neotype so we can have conclusive Spinosaurus arms.

Links:
Instagram. dream.fossils:

https://www.instagram.com/p/DPGhGafD1Nd/?img_index=1

-V2:

https://www.instagram.com/p/DPGhGafD1Nd/
Fandom. Dinopedia. HUGE NEWS! ...As promised: Another giant 13-14 meters Spinosaurus specimen in private hands:

https://dinopedia.fandom.com/f/p/4400000000000144128
Facebook. PNSO. Essien the Spinosaurus 3: The Forelimbs:

https://www.facebook.com/pnso.us/videos/essien-the-spinosaurus-3-the-forelimb-learn-to-draw-dinosaurs-with-zhao-chuang/1233529810713691/

(News) New Giant Titanosaur Coexisted with Giganotosaurus!

New 2021 titanosaur (MOZ Pv 1221) with other smaller sauropods from the Candeleros Formation (Otero et al., 2021. Figure 5) (Scale bar is 2 meters):

Last year, I wrote a post that talked about a possible specimen of giant sauropod (probably a titanosaur, and either closely related to, or is, Argentinosaurus) from the Candeleros Formation. Now, it seems that there is another titanosaur that coexisted with Giganotosaurus in the Candeleros Formation. It is said to have even 40 tons or more, and even been bigger than Patagotitan and probably Argentinosaurus (Otero et al., 20201, "Abstract") (Ian Randall, 2021) (Amy Woodyatt, 2021) (Bob Yirka, 2021)! The specimen is catalogued as MOZ Pv 1221.

MOZ Pv 1221 Phylogenetic Tree (Figure 4):

Discovery Site and List of Bones (Figure 1):

Scale bar length for silhouette of titanosaur is 2 meters:

Coracoid (Figure 3): 

Scale bar for coracoid is 10 cm:

Caudal (Tail) Vertebrae (Figure 2):

Scale bar for caudal vertebrae is 10 cm:

Centrum lengths for caudal vertebrae (Table 1):

I said in my post on the probable (?)Argentinosaurus specimen from Candeleros Formation that it was weird that Giganotosaurus carolinii never had giant titanosaurs to hunt within the Candeleros Formation, while it probably did hunt Patagotitan since it lived in the Albian alongside G. carolinii, but it came from a different formation. G. (Mapusaurus) roseae always hunted larger titanosaurs (Argentinosaurus and Puertasaurus, to name a few) than G. carolinii did in the Candeleros Formation (only the 80-foot long Andesaurus, but that (?)Argentinosaurus specimen is still there...). Perhaps this new unnamed giant titanosaur is related to that (?)Argentinosaurus/mystery titanosaur from Calvo (1999)? 

All I know is that G. carolinii finally has a giant titanosaur to tangle with! I will try to extrapolate a length for this animal once I can get the measurements! For now, I would say that this new titanosaur might be the same size, or perhaps bigger, than Patagotitan, just to be safe.

Size Estimation of MOZ Pv 1221:
I can't access the actual paper, but I've decided to try and formulate a size estimate for MOZ Pv 1221. 

Caudal Vertebra:
I decided to do the vertebra first. I measured the centrum length of caudal 4 (C4). I don't know how long the scale bar is, so I measured it using an estimated 5 and 10 cm each. Using 5 cm, I obtained a length of 18 cm for the centrum. Using 10 cm, I got 35 cm. I compared the centrum length of MOZ Pv 1221 to Dreadnaughtus.

1. Caudal Centrum 4:
Dreadnaughtus:
Centrum 4 Length: 33 cm.
Body Length: 30 m.

18 - 33 = 15.
15/33*100 = 45.5% decrease.
30 m - 45.5% = 54 feet (16.4 meters).

35 - 33 = 2.
2/33*100 = 6.1% increase.
30 m + 6.1% = 104 feet (31.8 meters).

Patagotitan:
Holotype's Centrum 4 Length: 36 cm (Carballido et al., 2017, Supplementary Materials, p. 32).
Body Length: 47.3 meters.

35 - 36 = 1.
1/36*100 = 2.8% decrease.
47.3 m - 2.8% = 151 feet (46.0 meters).

*Actual length: 32 cm.

Dreadnaughtus:
Centrum 4 Length: 33 cm.
Body Length: 30 m.

33 - 32 = 1.
1/33*100 = 3% decrease.
30 m - 3% = 96 feet (29.1 meters).

2. Caudal Centrum 11:
Length: 29 cm.

Dreadnaughtus:
Centrum 4 Length: 27.2 cm.
Body Length: 30 m.

27.2 - 29 = 1.8.
1.8/27.2*100 = 6.6% increase.
30 m + 6.6% = 105 feet (32.0 meters).

Caudal centrum 11 is unknown in Patagotitan.

Coracoid:
I measured MOZ Pv 1221's coracoid second.

5 cm: 41 cm.
*10 cm: 82 cm.

Patagotitan Holotype:

Coracoid: 61.5 cm (Carballido et al., 2017, Supplementary Materials, p. 33).

Body: 47.3 m.

41 - 61.5 = 20.5.

20.5/61.5*100 = 33.3% decrease.

47.3 m - 33.3% = 104 feet (31.6 meters).

*82 - 61.5 = 20.5

20.5/61.5*100 = 33.3% increase.

47.3 m + 33.3% = 207 feet (63.1 meters).

Dreadnaughtus:
Coracoid Length: 68 cm (Left).
Body Length: 30 m.

41 - 68 = 27.
27/68*100 = 39.7% decrease.
30 m - 39.7% = 59 feet (18.1 meters).

*82 - 68 = 14.
14/68*100 = 20.6% increase.
30 m + 20.6% = 119 feet (36.2 meters).

Update (2/3/21): The pubis has been stated as being 10% longer than Patagotitan's (Mercedes Benialgo, 2021, para. 4) (Madeleine Muzdakis, 2021, para. 3). 

Mercedes Benialgo (2021) (Para. 4) (Translated):

Madeleine Muzdakis (2021) (Para. 3):

Only the holotype of Patagotitan (MPEF-PV 3400) has its pubis (140 cm) preserved (Carballido et al., 2017, Supplementary Materials, p. 34), and I got a length of 47.3 meters for it.

47.3 m + 10% = 171 feet (52.0 meters) for MOZ Pv 1221.
140 cm + 10% = 154 cm for MOZ Pv 1221's pubis.

If the scale bar for the silhouette of the titanosaur in the "Discovery Site and List of Bones" figure picture is 2 meters, then I've obtained a measurement of about 130 cm (at best) for the pubis. 

Update (2/9/21): Scale bar is 2 meters, but the pubis length is 166 cm (Discussion, para. 8):

Pubis:
Length: 166 cm.

*Patagotitan Holotype:
140 - 166 = 26.
26/140*100 = 18.6% increase.
47.3 m + 18.6% = 184 feet (56.1 meters).

*New Patagotitan pubis length: 152 cm (Otero et al., 2020, p. 9 Table 2).

152 - 166 = 14.
14/152*100 = 9.2% increase.
47.3 m + 9.2% = 170 feet (51.7 meters).

Dreadnaughtus:
Pubis: 140 cm.
Body Length: 30 cm.

140 - 166 = 26.
26/140*100 = 18.6% increase.
30 m + 18.6% = 117 feet (35.6 meters).

Futalognknosaurus:
Pubis: 137 cm (Calvo et al., 2007, p. 521).
Body Length: 31.1 meters.

137 - 166 = 29.
29/137*100 = 21.2% increase.
31.1 m + 21.2% = 124 feet (37.7 meters).

In total, MOZ Pv 1221 was 170 feet long (51.7 meters), based on the pubis compared to the holotype of Patagotitan. Based on the coracoid, a wider range of 119-207 feet (36.2-63.1 meters) was obtained. I'll go with 51.7 meters, since the authors keep using the pubis length to give their estimate. 

As to whether or not MOZ is Argentinosaurus, the authors say that they don't know. Argentinosaurus is extremely fragmentary, so more MOZ bones will have to be excavated to see if it is a specimen of Argentinosaurus ("Discussion" para. 4):

There might be hope yet that MOZ is Argentinosaurus, and that Argentinosaurus coexisted with Giganotosaurus. However, that question will have to remain open.

Link:
Otero et al., (2021):
"Abstract":
https://www.sciencedirect.com/science/article/abs/pii/S019566712100001X
Link 2:
https://www.researchgate.net/publication/348461418_Report_of_a_giant_titanosaur_sauropod_from_the_Upper_Cretaceous_of_Neuquen_Province_Argentina
Specimen Name:
https://images.app.goo.gl/y3PyKdTeR8oA4e647
Discovery and List of Bones:
https://images.app.goo.gl/6PKmajb6s6KYZZCr5
Coracoid:
https://images.app.goo.gl/tvGwXytxtSigtrT76
Caudal (Tail) Vertebrae:
https://images.app.goo.gl/iveF5JwBh2LqRcG96
Mercedes Benialgo (2021) (Para. 4):
https://www.conicet.gov.ar/cientificos-del-conicet-hallan-un-gigantesco-dinosaurio-cuello-largo-en-neuquen/?fbclid=IwAR0jfIA8pgkgncKmN0Q9HJnV_vlYGU_tD7SpAkNLcTVgFiU885zpa0TlrAs
Madeleine Muzdakis (2021) (Para. 3): 
https://mymodernmet.com/dinosaur-fossil-titanosaur-argentina/
Ian Randall (2021):
https://www.dailymail.co.uk/sciencetech/article-9160381/Fossils-98-million-year-old-dino-unearthed-Argentina-largest-land-animal-ever.html
Amy Woodyatt (2021):
https://www.cnn.com/2021/01/19/americas/dinosaur-largest-titanosaur-intl-scli-scn/index.html
Bob Yirka (2021):
https://phys.org/news/2021-01-gigantic-dinosaur-unearthed-argentina-largest.html
My 2020 post on (?)Argentinosaurus/giant titanosaur from Candeleros Formation:
https://psdinosaurs.blogspot.com/2020/08/a-giant-sauropod-argentinosaurus-from_22.html
My lengths for the other titanosaurs mentioned in this post:
https://psdinosaurs.blogspot.com/2018/12/size-calculations-for-herbivorous.html
Lacovara et al., (2014):
https://www.researchgate.net/publication/265377777_A_Gigantic_Exceptionally_Complete_Titanosaurian_Sauropod_Dinosaur_from_Southern_Patagonia_Argentina
Link 2:
https://www.nature.com/articles/srep06196
Supplementary Materials:
https://static-content.springer.com/esm/art%3A10.1038%2Fsrep06196/MediaObjects/41598_2014_BFsrep06196_MOESM1_ESM.pdf
Carballido et al., (2017):
http://rspb.royalsocietypublishing.org/content/284/1860/20171219
Supplementary Materials (Pg. 32-34):
https://figshare.com/articles/Electronic_Supplementary_material_from_A_new_giant_titanosaur_sheds_light_on_body_mass_evolution_among_sauropod_dinosaurs/5297611
Otero et al., (2020) (P. 9 Table 2):
https://www.researchgate.net/publication/344346605_The_Appendicular_Osteology_of_Patagotitan_Mayorum_Dinosauria_Sauropoda
Calvo et al., (2007) (P. 521):
https://www.researchgate.net/publication/237289209_Anatomy_of_Futalognkosaurus_dukei_Calvo_Porfiri_Gonzalez_Riga_Kellner_2007_Dinosauria_Titanosauridae_from_the_Neuquen_Group_Late_Cretaceous_Patagonia_Argentina 

Size Calculations for Crocodyliformes:

 The Percentage Increase/Decrease Method:
1. Take new number and subtract it from original number.
2. Take that number and divide it by the original number and multiply by 100.
3. That number will by your percentage increase or decrease if it's negative.

Ex.: "Stan's" Femur is 130 and has a body length of 12.2 meters. "Wyrex" has a femur length of 132.7 cm.

132.7 - 130 = 2.7.
2.7 divided by (represented by "/") and multiplied by (represented by "*") equals 2.1.
(2.7/130*100 = 2.1)
2.1 is your percentage increase, or 2.1% increase.
12.2 m + 2.1% = 12.5 meters for "Wyrex."

Links:
Percentage Increase/Decrease Method Links:
"Percentage Change - Percentage Increase and Decrease." SkillsYouNeed:

https://www.skillsyouneed.com/num/percent-change.html
"Relative Increase." percentage.calculators.ro:
https://percentages.calculators.ro/15-percentage-increase-from-original-number-to-new-value.php

Model: Florida Alligator:
Skull: 26 cm (10 1/4 inches).
Body: 6 feet.

Link:
Worldwide Wildlife Products. "Alligator Skulls": "10-1/4 Alligator Skull":
https://www.worldwidewildlifeproducts.com/store/pc/10-1-4-inches-Good-Quality-Florida-Alligator-Skull-for-Sale-You-are-buying-this-one-for-59-99-125p7589.htm

1. Cerrejonisuchus:

Skulls (Largest): 31.4 cm (Table 1).

26 - 31.4 = 5.4.

5.4/26*100 = 20.8% increase.

1.829 m + 20.8% = 7 feet (2.2 meters).

Cerrejonisuchus' Total Length: 7 feet (2.2 meters).

Link: 

https://www.tandfonline.com/doi/full/10.1080/02724630903409204

2. Eothoracosaurus:

MSU 3293:
Skull: 89.7 cm (For now).

Cerrejonisuchus:

Skulls (Largest): 31.4 cm.

Body: 2.2 meters.

89.7 - 31.4 = 58.3.

58.3/31.4*100 = 185.7% increase.

2.2 m + 185.7% = 21 feet (6.3 meters).

Eothoracosaurus' Total Length: 21 feet (6.3 meters).

Links:

Carpenter (1983) (Pg. 4 Table 1 [24-33]): 

https://www.mdeq.ms.gov/wp-content/uploads/2013/10/Vol_4_1.pdf

Species Name:
Brochu (2004): https://www.researchgate.net/publication/40662929_A_new_Late_Cretaceous_gavialoid_crocodylian_from_eastern_North_America_and_the_phylogenetic_relationships_of_Thoracosaurs

Link 2: 

https://www.jstor.org/stable/4524750?seq=1

Time:

Fossilworks. "Eothoracosaurus": 

http://fossilworks.org/bridge.pl?a=taxonInfo&taxon_no=176554

Fossilworks. "Eothoracosaurus mississippiensis": 

http://fossilworks.org/bridge.pl?a=taxonInfo&taxon_no=176555

Family Tree:
Lee and Yates (2018) (Figure 1):
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6030529/

3. Elosuchus:
Carcharodontosaurus and Elosuchus by David Bonadonna:

Largest Skull: 107.7 cm (Meunier and Larsson, 2017, Table 1).

Eothoracosaurus:

Skull: 89.7 cm.

Body: 6.3 m.

107.7 - 89.7 = 18.

18/89.7*100 = 20.1% increase.

6.3 m + 20.1% = 25 feet (7.6 meters).

Elosuchus' Total Length: 25 feet (7.6 meters).

Link:
Meunier and Larsson (2017) (Table 1):
https://academic.oup.com/zoolinnean/article/179/1/169/2870024
Picture:
David Bonadonna:
http://www.davidebonadonna.it/project/342/

4. Sarcosuchus:
Sarcosuchus vs. Suchomimus:

1. MNN 604:

Skull: 150 cm (Sereno et al., 2001, pg. 1518 Table 1).

Elosuchus:

Skull: 107.7 cm.

Body: 7.6 meters.

107.7 - 150 = 42.3.

42.3/107.7*100 = 39.3% increase.

7.6 m + 39.3% = 35 feet (10.6 meters).

Link: 
Sereno et al., (2001) (Pg. 1518 Table 1):

https://www.researchgate.net/publication/11672584_The_Giant_Crocodyliform_Sarcosuchus_from_the_Cretaceous_of_Africa

2. BC-156:
Skull: 172.7 cm (Bone Clones).

Deinosuchus:

Skull: 167.6 cm.

Body: 11.8 m.

167.6 - 172.7 = 5.1.

5.1/167.6*100 = 3% increase.

11.8 m + 3% = 40 feet (12.2 meters).

Link: 
Bone Clones: 

https://boneclones.com/product/sarcosuchus-imperator-supercroc-skull-BC-156
Time Period:
Barremian and Older:
Douiret Formation:
Loeuff et al., (2010) (Pg. 753-754, 756-757):
http://doc.rero.ch/record/293777/files/S0016756810000178.pdf
El Rhaz Formation:
Bertozzo et al., (2017) ("Introduction"): 
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5480399/
Loeuff et al., (2012) (Pg. 3 and 8):
https://www.researchgate.net/publication/284617900_Between_Tendaguru_and_Bahariya_on_the_age_of_the_Early_Cretaceous_dinosaur_sites_from_the_Continental_Intercalaire_and_other_African_formations
Others:
Souza et al., (2019) (Pg. 2-3, and 5):
https://paleontologia.ufes.br/sites/paleontologia.ufes.br/files/field/anexo/souza_et_al._2019_-_sarcosuchus_0.pdf
Barremian-Aptian:
Contessa, Michela. Paleontological studies of Cretaceous vertebrate fossil beds in the Tataouine Basin (southern Tunisia). Pg. 12-13. 2013:
http://amsdottorato.unibo.it/5240/1/Contessi_Michela_tesi.pdf

Aptian-Albian:
Dridi (2018):
https://www.sciencedirect.com/science/article/pii/S1464343X18301778?via%3Dihub
Albian:
Contessa, Michela. Paleontological studies of Cretaceous vertebrate fossil beds in the Tataouine Basin (southern Tunisia). 2013:
http://amsdottorato.unibo.it/5240/1/Contessi_Michela_tesi.pdf
Notes:
Age:
Pg. 14: Albian.
Fossils:
All: Pages 20-29; Sarcosuchus: Pg 25-26, 28; Spinosaurus, Carcharodontosaurus, and ornithopod: Pg 27-29).

Sarcosuchus' Total Length: 35-40 feet (10.6-12.2 meters).

5. Deinosuchus:
Deinosuchus vs. Albertosaurus or Gorgosaurus:

Skull: 5.5 feet/5 feet 6 inches (167.6 cm) (Prehistoric Planet Store) (Bay State Replicas).

Sarcosuchus holotype:

Skull: 150 cm.

Body: 10.6 m.

150 - 167.6 = 17.6.

17.6/150*100 = 11.7% increase.

10.6 m + 11.7% = 39 feet (11.8 meters).

Deinosuchus' Total Length: 39 feet (11.8 meters).

Link: 
Prehistoric Planet Store:

http://www.prehistoricstore.com/item.php?item=1475

Bay State Replicas: 

http://www.baystatereplicas2.com/product/deinosuchus-skull/

6. Purussaurus:

Skull (Mandible): 175 cm (Aureliano et al., 2015, "Introduction" p. 4).

Sarcosuchus Specimen 2:

Skull: 172.7 cm.

Body: 12.2 m.

175 - 172.7 = 2.3.

2.3/172.7*100 = 1.3% increase.

12.2 m + 1.3% = 41 feet (12.4 meters).

Purussaurus' Total Length: 41 feet (12.4 meters).

Link: 
Aureliano et al., (2015) ("Introduction" p. 4):

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0117944

7. Stomatosuchus:
Skull from Paleofile:

Skull: 2 meters (Stromer, 1925, pg. 1) (Stromer, 1933, pg. 45).

Purussaurus:

Skull (Mandible): 175 cm.
Body: 12.4 meters.

175 - 200 = 25.

25/175*100 = 14.3% increase.

12.4 m + 14.3% = 47 feet (14.2 meters).

Stomatosuchus' Total Length: 47 feet (14.2 meters).

Links:
Stromer (1925) (Pg. 1):

https://www.zobodat.at/pdf/Abhandlungen-Akademie-Bayern_30_0001-0022.pdf

Stromer (1933) (Pg. 45):

https://www.zobodat.at/pdf/Abhandlungen-Akademie-Bayern_NF_15_0001-0055.pdf
Skull Pic:
Paleofile:
https://images.app.goo.gl/uwizbwGoJxtrJgsNA

What If: A Giant Sauropod (Argentinosaurus?) from the Candeleros Formation.

For the second post in my "What If" series, I'll be discussing whether or not Argentinosaurus actually lived in the Candeleros Formation.

Argentinosaurus from Dinosaurs: Giants of Patagonia:

Like I mentioned before in my "Were Giganotosaurus and Mapusaurus the Same Genus?" post, I was told, and read, some things about Giganotosaurus and Mapusaurus that contradicted each other over the years. After examining the two animals' skeletons, and looking up how old their formations are, I've come to three conclusions: 

1. Mapusaurus (10.9-15.3 meters) is bigger than Giganotosaurus (12.4-13.1 meters). This makes sense because, back in the day, I read that Giganotosaurus didn't coexist with Argentinosaurus, and that it hunted smaller titanosaurs (despite being 13.2 meters long). Mapusaurus was the carcharodontosaurid that coexisted with Argentinosaurus, despite being 10.2 meters long. Why would a carcharodontosaurid, which evolved after a larger carcharodontosaurid, get smaller in order to hunt a larger animal? Now I know that isn't the case. We'll get back to Argentinosaurus shortly.

2. Giganotosaurus and Mapusaurus seem to have coexisted, based on microfossils discovered, and U-Pb dating done, in the Candeleros and Huincul Formations.

3. Mapusaurus roseae seems to be a species of Giganotosaurus: Giganotosaurus roseae. I mainly go with Giganotosaurus (Mapusaurus) roseae. 

Now, we'll talk about Argentinosaurus again. Back when I thought that Giganotosaurus was bigger than Mapusaurus, I was perplexed when I read/was told that Giganotosaurus hunted Andesaurus, not Argentinosaurus. It confused me because Andesaurus was only 80 feet long (24.4 meters). This is small compared to the 170-foot long (51.8 meters) Argentinosaurus. I asked myself this question for years: How could the larger Giganotosaurus hunt such a smaller sauropod, while the smaller Mapusaurus hunted a bigger sauropod? Nowadays, with a larger size for Mapusaurus, along with the possibility of Mapusaurus roseae being Giganotosaurus roseae, based on my analysis, I don't fret over this question anymore. This is not the end of the story though.

A couple of years ago now, I read in Calvo (1999) about the bones of a large sauropod, called Sauropoda gen. et sp. indet., discovered in the Candeleros Formation, which is the same formation that Giganotosaurus carolinii came from. Labelled as MUCPv-251, it consisted of a possible dorsal vertebra and rib. It seems to have come from a large sauropod, and Calvo says that it might be related to Argentinosaurus (pg. 26). 

Statement on the specimen from Calvo (1999) (P. 26):

Info. on MUCPv-251 from Calvo (1999) (Pg. 26):

-Consists of a dorsal vertebra and rib.
-Rib is 175 cm long, but it's partial/the proximal half. ("Proximal" means closer to the body, as explained by Merriam-Webster and Lexico)
-Width at proximal end: 21 cm.
-Width at distal end: 12 cm.

-Rib is probably a dorsal, but I'm making that assumption because Calvo says that the vertebra found with the rib is probably a dorsal.
-Calvo thinks there's a possibility that these bones could be related with Argentinosaurus. However, I can't find any other papers that talk about this specimen.

Last year or so, I tried to find a way to estimate a length for this animal, but I couldn't find one. I was use to estimating dinosaur lengths based on limb and skull bones, not ribs. However, using the bones of the Chinese titanosaur Ruyangosaurus, I was able to get a size estimate for MUCPv-251.

Size Estimates for MUCPv-251:

1. Proximal Part of Rib Length:

Ruyangosaurus:

Dorsal Rib Length: 127 cm (proximal portion) (Sassani and Bivens, 2017, pg. 8).

Length: 47.1 meters.

127 - 175 = 48.

48/127*100 = 37.8% increase.

47.1 m + 37.8% = 213 feet (64.9 meters).

Hypothetically Complete Rib for Ruyangosaurus:
"Huangetitan" ruyangensis' Largest Dorsal Rib Length: 293 cm (Sassani and Bivens, 2017, pg. 28).
Width: 17.2 cm (Sassani and Bivens, 2017, pg. 15).

Ruyangosaurus' Dorsal Rib Width: 18 cm (Sassani and Bivens, 2017, pg. 15).

Dorsal Rib Length (Proximal half only): 127 cm (Sassani and Bivens, 2017, pg. 8).
Body Length: 47.1 meters.

17.2 - 18 = 0.8.
0.8/17.2*100 = 4.7% increase.
293 cm + 4.7% = 306.8 cm for Ruyangosaurus' complete dorsal rib.

Hypothetically Complete Rib for MUCPv-251:

Ruyangosaurus:

Dorsal Rib Length (Complete): 306.8 cm.
Width: 18 cm (Sassani and Bivens, 2017, pg. 15). 

Length: 47.1 meters.

21 - 18 = 3.
3/18*100 = 16.7% increase.
306.8 + 16.7% = 358 cm for MUCPv-251's complete dorsal rib.

2. Hypothetically Complete Rib Length:

Ruyangosaurus:

Dorsal Rib Length (Complete): 306.8 cm.
Width: 18 cm (Sassani and Bivens, 2017, pg. 15). 

Length: 47.1 meters.

306.8 - 358 = 51.2.
51.2/306.8*100 = 16.7% increase.
47.1 m + 16.7% = 181 feet (55.0 meters).

MUCPv-251's Total Length: 181 feet (55.0 meters).

Is MUCPv-251 Argentinosaurus?
Now that we have a size estimate for MUCPv-251, the question we have to ask now is whether or not MUCPv-251 belongs to Argentinosaurus, let alone a titanosaur? Based on the sauropod fauna discovered in the Candeleros Formation, consisting on the titanosaurs Andesaurus (80 feet long; 24.4 meters) and MMCH-Pv 47 (81 feet; 24.7 meters), and the rebbachisaur Limaysaurus (71-84 feet; 21.5-25.6 meters). Limaysaurus was bigger than the two titanosaurs, but its ribs were small. 

Limaysaurus Skeleton:

I think the size of MUCPv-251 seems to put it in the titanosaur family. The width of the rib matches the widths of the titanosaurs Ruyangosaurus' and "Huangetitan" ruyangensis' rib widths. In fact, MUCPv-251's rib width was larger than both of them. Width aside, the size of this animal's bones puts it up there with Argentinosaurus! Argentinosaurus was 167 feet long (51.8 meters). Based on my estimates, MUCPv-251 was 181 feet long (55.0 meters). It was larger than Argentinosaurus!

Argentinosaurus was the largest titanosaur from South America. However, no Argentinosaurus fossils were discovered in the Candeleros Formation... As far as I know. However, MUCPv-251 seems to suggest that this might not be the case. What we do know is that its bones belong to a sauropod, as stated in Calvo (1999). Based on the size of the bones, the animal seems to have been a titanosaur. It might not be too 

crazy to say that this animal was Argentinosaurus. A couple of sauropod dinosaurs from the Candeleros and Huincul Formations were found in other formations. Limaysaurus was discovered in both the Candeleros and Huincul Formations (Calvo and Salgado, 1995, pg. 15). Andesaurus was discovered in the Candeleros (Calvo, 1999, pg. 16, 22-24) (Calvo and Salgado, 1995, pg. 14), but also in the Bajo Barrea Formations. A titanosaur caudal vertebra was discovered there that has been attributed to Andesaurus (Casal et al., 2016, pg. 57). The Bajo Barrea Formation has been dated from the Albian-Turonian (Casal et al., 2009, "Abstract," "Introduction" p. 1). Pollen and spore samples assigned it to the Albian-Cenomanian, but radiometic dating (Ar/Ar), and U-Pb dates, place it at 99-91 million years (Casal et al., 2016, pg. 56, "Edad de la Formacion Bajo Barreal"). Therefore, the Bajo Barrea Formation is 113-90 million years old (Albian-Turonian), and so is Andesaurus. Therefore, we cannot throw out the possibility that MUCPv-251 could be the first fossils of Argentinosaurus from the Candeleros Formation.

Based on microfossils and U-Pb dating, the Huincul Formation was also Albian-Cenomanian in age (Vallati (2001) ("Abstract") (List of Microflora), Vallati (2006) ("Abstract"), Musacchio and Vallati (2007) ("Introduction"), and Vallati (2013) ("Paleotropical representatives in Northern Patagonia" 1-1.2, "Conclusions") (Corbella et al., 2004, "Abstract," "Characteristics and radiometric age of the tuff bed" pg. 229) (Garrido, 2010, pg. 138), just like the Candeleros Formation (Baez et al., 2000, pg. 491, "Geological Setting") (David Cannatella, 2015, "Temporal Data: Ages of Fossils and Calibration Priors," p. 20) (Tunik et al., 2010, pg. 270-271) (Di Giullo et al., 2012, pg. 600 "Results") (Garrido, 2010, pg. 134) (Halupczok et al., 2017, "Geological setting" pg. 2). The time frame of both formations makes it even more likely that MUCPv-251 could actually be Argentinosaurus.

The only other titanosaurs from the Candeleros Formation is Andesaurus and MMCH-Pv 47. Andesaurus is probably too small to be the real genus, but we only have one specimen to demonstrate this (Mannion and Calvo, 2011, "Additional Remains Referred To Andesaurus" p. 3). Perhaps Andesaurus grew larger than we've previously thought? I would like to think so, but this cannot be verified. Based on the skeleton we have now, Andesaurus is too small to be the real genus of MUCPv-251. MMCH-Pv 47 is slightly larger than Andesaurus, but we only have its vertebrae and no ribs. MMCH-Pv 47 is an unidentified titanosaur as well, so maybe comparing MUCPv-251 to it wouldn't be the best choice. Along with that, I cannot compare the specimens either way because I don't have a picture of MUCPv-251's bones. All I have are the size and width of its dorsal width. Therefore, based on the size, and width, of the bones, perhaps MMCH-Pv 47 isn't the real genus either. It's still small compared to Argentinosaurus.

Since I cannot find any other sources on MUCPv-251 other than Calvo (1999), I will place it as a titanosaur. Based on the size of the bones, this could possibly be the oldest recorded specimen of Argentinosaurus.

Update (2/4-9/21): A new large titanosaur has been discovered in the Candeleros Formation! Based on the size of the 166-cm long pubis, the animal was 170 feet long (51.7 meters), with a wider range of 119-207 feet (36.2-63.1 meters) based on the coracoid. Whether or not this mystery titanosaur is the owner of MUCPv-251 is unknown, but it's a possibility. However, this new titanosaur, catalogued as MOZ Pv 1221, proves that Giganotosaurus carolinii lived alongside massive sauropods!

As to whether or not MOZ is Argentinosaurus, the authors say that they don't know. Argentinosaurus is extremely fragmentary, so more MOZ bones will have to be excavated to see if it is a specimen of Argentinosaurus ("Discussion" para. 4):

There might be hope yet that MOZ is Argentinosaurus, and that Argentinosaurus coexisted with Giganotosaurus. However, that question will have to remain open.

Links on 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

Links: 
Calvo (1999) (Pg. 26):
https://www.researchgate.net/publication/284053211_Dinosaurs_and_other_vertebrates_of_the_Lake_Ezequiel_Ramos_Mexia_Area_Neuquen-Patagonia_Argentina
Merriam-Webster. "Proximal":
https://www.merriam-webster.com/dictionary/proximal
Lexico. "Proximal":
https://www.lexico.com/en/definition/proximal

Sassani and Bivens (2017) (Pg. 7-8, 15, and 28):

https://www.researchgate.net/publication/332553212_The_Chinese_colossus_an_evaluation_of_the_phylogeny_of_Ruyangosaurus_giganteus_and_its_implications_for_titanosaur_evolution

Link 2:
https://peerj.com/preprints/2988v1.pdf

Mannion and Calvo (2011) ("Additional Remains Referred To Andesaurus" p. 3):

https://academic.oup.com/zoolinnean/article/163/1/155/2625609

Sizes of Other Sauropods:
https://psdinosaurs.blogspot.com/2018/12/size-calculations-for-herbivorous.html
Time of Candeleros and Huincul Formations:
https://psdinosaurs.blogspot.com/2020/07/were-giganotosaurus-and-mapusaurus-same_24.html
Sellers et al., (2013):
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3864407/