Saturday, March 9, 2019

Size Calculations for Spinosaurs.

For a long time, I've heard that the spinosauridae were the largest species of theropod to have ever walked the Earth. This started with the Spinosaurus holotype. Paleontologists Scott Hartman in 2013 gave it 14.0 meters, while Jack Horner gave it 60 feet in 2001. Jack Horner's size estimate was a huge overestimate for the holotype, so it doesn't count anymore. Then the spinosauridae indet. specimen MSNM V4047 was discovered, and then Spinosaurus was given 16.0-18.0 meters (Dal Sasso et al., 2005). Scott Hartman in 2013 gave it 15.6 meters. Then Oxalaia was discovered in 2010, and it was given 12-14 meters (Kellner et al., 2010). Then in 2014, Ibrahim et al., (2014) made a Spinosaurus skeleton that was stated to have been 15.0-15.2 meters (Ibrahim et al., 2014) (Paul Sereno, 2014). Then Henderson (2018) gave it 15.6 meters.

Links:
Scott Hartman (2013):
http://www.skeletaldrawing.com/home/super-spinosaurus6282013
Ibrahim et al., (2014):
https://www.researchgate.net/publication/265553416_Semiaquatic_adaptations_in_a_giant_predatory_dinosaur
Paul Sereno (2014):
https://paulsereno.uchicago.edu/discoveries/spinosaurus_aegyptiacus/
Donald M. Henderson (2018):
https://peerj.com/articles/5409/

For a long time, I believed these sizes to be true, but recently a lot of things have happened that made me question these lengths. For starters, the Spinosaurus skeleton, created by Ibrahim et al., (2014), was proven to have included bones from not only Spinosaurus but its relative Sigilmassasaurus (Evers et al., 2015) (Hendrickx et al., 2016). Thus, Spinosaurus was no longer over 15.0 meters long. That title seems to have belonged to Sigilmassasaurus. Arden et al., (2018) assigned MSNM V4047 to Sigilmassasaurus but Lakin and Longrich (2018) said that MSNM V4047 didn't seem to belong to Spinosaurus or Sigilmassasaurus, and said that it belonged to an unnamed species of spinosauridae. Therefore, both Spinosaurus and Sigilmassasaurus might not be the longest species of spinosaur. As you can see, the whole "who's the biggest spinosaur debate" is a huge headache, but how big were these animals really?

Well, I've started to do my own research on guessing dinosaur sizes. The spinosauridae have proven to be very difficult in getting an accurate size estimate. However, I've noticed something rather strange and alarming... It turns out that the spinosauridae have been overestimated in terms of their sizes. Here, I'm going to give the sizes of as many spinosaurs that I could find.

Here's my math:

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

Suchomimus:
Size estimate: 11.0 meters (Sereno et al., 1996)

Skull: 119.0 cm. (Hendrickx et al., 2016)
Femur: 107.5 cm. (Sereno et al., 1998)

Allosaurus Specimen OMNH 0112:
Femur: 113.5 cm. 
Body: 10.6 meters.

 Here's how I got OMNH 0112's body length:
https://psdinosaurs.blogspot.com/2018/10/calculations-for-largest-theropods.html

113.5 - 107.5 = 6.
6/113.5*100 = 5.3% decrease.
10.6 m - 5.3% = 33 feet (10.0 meters).

Note: Both Allosaurus and Suchomimus are carnosaurs (Rauhut and Pol, 2019, Figure 4).

Suchomimus' Total Length: 33 feet (10.0 meters).

Suchomimus' Stats (From Sereno et al., 1998):
Humerus: 56.0 cm.
Premaxilla: 33 cm. (Measured on 4/26/20 in Figure 2, "D")
Premaxilla to 7th aveoli/tooth: 12 cm. (Measured on 4/26/20 in Figure 2, "D")
Maxilla to Antorbital Fossa: 39.5 cm. (Measured on 4/26/20 in Figure 2, "D")
Dentary: 67.7 cm (at best). (Measured myself in Figure 2, "D")
Dentary Tooth Row: 46 cm (Measured on 3/20/21 in Figure 2 D).
Full Rostrum: 78 cm. (Measured myself in Figure 2, "A")
Premaxilla to Maxilla: 12.5 cm (Measured on 3/15/21 in Figure 2 D).
Maxilla: 59 cm (Measured on 3/14/21 in Figure 2 D).

Links:
Sereno et al., (1998):
Hendrickx et al., (2016) ("Size" Section):
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4703214/
Therrien and Henderson (2007) (pg. 111): 
https://docs.google.com/viewer?a=v&pid=sites&srcid=ZGVmYXVsdGRvbWFpbnxiYXJ5b255eHBkeHxneDo0MmEyZjA2MWEzM2Q1Mjhj
Rauhut and Pol (2019). Figure 4:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6906444/
Barremian Age for Suchomimus:

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


Baryonyx:
BMNH R9951 (Holotype):
Size estimate: 10 meters. (Charig and Miller, 1997, pg. 11)

Skull:
910-950 mm (Hendrickx et al., 2016).
91.5 cm. (Urzeitshop)
91 cm. (Therrien and Henderson, 2007, pg. 111)

I'll go with the 91-cm length.

Spinosaurus Neotype FSAC-KK 11888:
Skull: 112 cm.
Body: 9.4 meters.

 112 - 91 = 21.
21/112*100 = 18.8% decrease.
9.4 m - 18.8% = 25 feet (7.6 meters).

The holotype was a juvenile too (Charig and Miller, 1997, pg. 11), so 16 years at best(?).
Update (2/20/23):
Ibrahim et al., (2020b) said that Baryonyx was an adult.

Links:
Charig and Miller (1997):
https://www.biodiversitylibrary.org/page/36949178#page/201/mode/1up
Hendrickx et al., (2016) ("Size" Section):
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4703214/
Urzeitshop:
https://www.urzeitshop.de/gb/skulls/3053-baryonyx-walkeri-dinosaur-skull-replica-by-eofauna.html
Additional Info:
https://www.nhm.ac.uk/discover/how-did-baryonyx-change-what-we-knew-about-spinosaurs.html
Skeleton Picture:
https://www.rmdrc.com/darwin-and-dinosaurs/baryonyx-pic/

Baryonyx's Total Length: 25 feet (7.6 meters).
Age: 16(?). (My estimate)
Age 18: 27 feet (8.2 meters)(?). (My estimate)

Irritator (and Angaturama):
Irritator Specimen:
Rostrum Length: 43 cm. (Measured in Dal Sasso et al., 2005, including middle of crest)
Mazilla to Antorbital Fossa: 27 cm. (Measured on 5/9/20 in Dal Sasso et al., 2005, Figure 4).

Suchomimus: 
Skull: 119.0 cm.
Maxilla to Antorbital Fossa: 39.5 cm. 
Length: 10 meters.

27 - 39.5 = 12.5.
12.5/39.5*100 = 31.7% decrease.
10 m - 31.7% = 22 feet (6.8 meters).


Irritator's Total Length: 22 feet (6.8 meters).

Angaturama specimen:
Despite being larger than Irritator, both specimens lived during the Albian and were found in the same area (Sales and Schultz, 2017).

Rostrum Length: 69 cm. (Measured in Sales and Schultz, 2017, Figure 11, "B," including middle of crest)
Total(?) Skull Length: 87 cm (at best) (Up to first scale, as followed by "A"). (Measured on 5/9/20 in Sales and Schultz, 2017, Figure 11, "B").

Spinosaurus Neotype FSAC-KK 11888:
Skull: 112 cm.
Body: 9.4 meters.

87 - 112 = 25.
25/112*100 = 22.3% decrease.

Angaturama's Total Length: 24 feet (7.3 meters).

Since Sales and Schultz (2017) says that the specimens of each genera do seem to overlap due to: coming from the same stratigraphic unit (pg. 2-3), having a dorsal sagittal crest (pg. 18), and a tooth Lm3 (pg. 19). If these two genera are the same, then Angaturama would be Irritator (pg. 19). The authors conclude that the two specimens might have belonged to two different individuals, and that more overlapping material is needed (pg. 21). I will keep that in mind, but I think there is enough evidence to place Angaturama as Irritator for now, at least until more papers are published.

Dal Sasso et al., (2005) also combined the two genera into the same genus (pg. 894, Figure 3).

Irritator's Total Length: 22-24 feet (6.8-7.3 meters).

Spinosaurus:
1. FSAC-KK 11888 (Spinosaurus Neotype):
(Taken from Ibrahim et al., 2014, "Supplementary Materials"):
Skull: 112.0 cm. (Pg. 30)
Femur: 61 cm. (Pg. 30 and 33)
Age: 17. (Pg. 14)

Suchomimus:
Skull: 119.0 cm. (Hendrickx et al., 2016)
Femur: 107.5 cm. (Sereno et al., 1998)
Length: 10 meters.

Femur:
61 - 107.5 = 46.5.
46.5/107.5*100 = 56.7% increase.
10 m - 56.7% = 14 feet (4.3 meters) for neotype at age 17.
Age 18: 15 feet (4.6 meters).

Skull:
119.0 -112.0 = 7.
7/119*100 = 5.9% decrease.
10 m - 5.9% = 31 feet (9.4 meters) at age 17.
Age 18: 32 feet (9.8 meters).

The body length I obtained from the skull seems a lot more appropriate. Spinosaurus had a short femur compared to other spinosaurs.

FSAC-KK 11888's Total Length: 31 feet (9.4 meters). 
Age: 17.
Age 18: 32 feet (9.8 meters)(?). (My estimate)

Update (6/29/29): Skull Length: 123 cm (Ibrahim et al., 2020, Supplementary Materials, Body dimensions, body mass, body segment masses, and whole body center of mass pg. 1)

Suchomimus:
Skull: 119.0 cm. (Hendrickx et al., 2016)
Length: 10 meters.

119 - 123 = 4.
4/119*100 = 3.4% increase.
10.0 m + 3.4% = 34 feet (10.3 meters).

FSAC-KK 11888's Total Length: 34 feet (10.3 meters). 
Age: 17.

Link:
Ibrahim et al., (2014) ("Supplementary Materials," pg. 14, 30, and 33):
Ibrahim et al., (2020) (Supplementary Materials, Body dimensions, body mass, body segment masses, and whole body center of mass pg. 1):
https://www.readcube.com/articles/supplement?doi=10.1038%2Fs41586-020-2190-3&index=3

2. IPHG 1912 VIII 19 (Holotype):
Discovered by Ernst Stromer in 1915. According to his drawing, the animal was 30 feet long (9 meters):
Lakin and Longrich (2018) gave the same length (par. 3).

Mandible: 120 cm (Estimated). (Stromer, 1915, pg. 5)
Dentary: 60 cm (I think). (Stromer, 1915, pg. 5)

IPHG 1912 VIII 19's Dentary (Candiero et al., 2018, Figure 3, "A"):

-Length: 56 cm (Measured on 3/16/21, A).
-Dentary Tooth Row: 37 cm (Measured on 3/20/21, B).

Suchomimus:
Skull: 119.0 cm.
Dentary: 67.7 cm (at best). 
Dentary Tooth Row: 46 cm.
Length: 10 meters.

Mandible:
120.0 - 119.0 = 1.
1/119*100 = 0.8% increase.
10 m + 0.8% = 33 feet (10.1 meters)

Dentary:
67.7 - 65 = 2.7.
2.7/67.7*100 = 4% decrease.
10 m - 4% = 9.6 meters.

Update (10/26/20): Dorsal Vertebra "H" (6) Centrum Length: 19 (calculated) (Stromer, 1915, p. 24 "Measurements of Vertebrae in cm").

FSAC-KK 11888 (Neotype):
Dorsal Vertebra 6 Centrum Length: 17 cm (Ibrahim et al., 2014, Supplementary Materials, pg. 32).
Length: 10.3 meters.

19 - 17 = 2.
2/17*100 = 11.8% increase.
10.3 m + 11.8% = 38 feet (11.5 meters).

Update (12/17/20): Thoracic vertebra "h" is before "f" (Stromer, 1934, pg. 9). "G" from Stromer (1915) (p. 24) would be dorsal/thoracic vertebra 6.

Vertebra "g" Centrum Length: 17 cm (Stromer, 1915, pg. 25 "Measurements of Vertebrae in cm").

FSAC-KK 11888 (Neotype):
Dorsal Vertebra 6 Centrum Length: 17 cm (Ibrahim et al., 2014, Supplementary Materials, pg. 32).
Length: 10.3 meters.

Holotype's Length (Based on Neotype): 34 feet (10.3 meters).

*Update (9/14/23):
Dentary tooth row:

Suchomimus:
Dentary Tooth Row: 46 cm (Measured on 3/20/21 in Figure 2 D).
Body Length: 10.0 meters.

46 - 37 = 9.
9/47*100 = 19.2% decrease.
10 m - 19.2% = 27 feet (8.1 m).

IPHG 1912 VIII 19's Total Length: 27 feet (8.1 meters).

Links:
Ernst Stromer (1915):
-PP. 5 and 24 (Translated to English):
http://www.dinochecker.com/papers/Stromers-Egypt-expedition_Spinosaurus_Stromer_1915.pdf
-Pg. 24 (Original [Article 3]):
https://www.biodiversitylibrary.org/item/124817#page/126/mode/1up
Lakin and Longrich (2018):

3. MHNM.KK378:
Skull Length: 102.8-115.4 cm. (Hendrickx et al., 2016, Table 2)

I decided to try an obtain a length by using their quadrates.

Quadrate Height: 20.4 cm. (Hendrickx et al., 2016, Table 2)

FSAC-KK 11888:
Skull: 112.0 cm. (Ibrahim et al., 2014, pg. 30) (Hendrickx et al., 2016, pg. 27, Table 2)
Quadrate Height: 24 cm. (Hendrickx et al., 2016, pg. 27, Table 2)
Length: 9.4 meters.

24 - 22 = 2.
2/24*100 = 8.3% decrease.
112 cm + 8.3% = 102.7 cm.

I'm going with the 102.7-cm length. This is also an adult specimen.

FSAC-KK 11888:
Skull: 112.0 cm.
Length: 9.4 meters.

102.7-112 = 9.3.
9.3/112*100 = 8.3% decrease.
9.4 m - 8.3% = 28 feet (8.6 meters).

*Update (6/29/20):
Quadrate:
24 - 22 = 2.
2/24*100 = 8.3% decrease.
123 cm - 8.3% = 112.8 cm.

Skull:
FSAC-KK 11888:
Skull: 123 cm.
Length: 10.3 meters.

112.8 -123 = 10.2.
10.2/123*100 = 8.3% decrease.
10.3 m - 8.3% = 31 feet (9.5 meters).

Suchomimus: 
Skull: 119.0 cm.
Length: 10 meters.

119 - 112.8 = 6.2.
6.2/119*100 = 5.2% decrease.
10 m - 5.2% = 31 feet (9.5 meters).

Link:

4. NHMUK VP R 16421:
Dentary (Ibrahim et al., 2020, Figure 125, "A") (Scale bar is 20 cm):
Length: 75.5 cm (at best) (Remeasured on 3/20/21).
Tooth Row Length (From tip of dentary to 16th alveoli): 69 cm.
Dentary/tooth row length up to 4th tooth: 17 cm (at best) (Figure 125C).

Suchomimus:
Skull: 119.0 cm.
Dentary: 67.7 cm (at best). 
Dentary Tooth Row: 46 cm.
Dentary tooth row up to 16th tooth: 
Length: 10 meters.

Dentary:
67.7 - 75.5 = 7.8.
7.8/67.7*100 = 11.5% increase.
10 m + 11.5% = 37 feet (11.2 meters).

Dentary Tooth Row:
46 - 69 = 23.
23/46*100 = 50% increase.
10 m + 50% = 49 feet (15.0 meters).

*Update (9/14/23):
IPHG 1912 VIII 19's Dentary:
Length: 56 cm.
Dentary Tooth Row: 37 cm.
Dentary/tooth row length up to 4th tooth: 11 cm (at best) (Candiero et al., 2018, Figure 3B).
Body Length: 27 feet (8.1 meters).

There's about 15-16 teeth in the holotype's dentary, just like NHMUK's.

Dentary tooth row:
37 - 69 = 32.
32/37*100 = 86.5% increase.
8.1 m + 86.5% = 50 feet (15.1 meters).

Dentary length up to 4th tooth:
11 - 17 = 6.
6/11*100 = 54.6% increase.
8.1 m + 54.6% = 41 feet (12.5 meters).

NHMUK VP R 16421's Total Length: 41 feet (12.5 meters).

Update (4/24/20): All other spinosaurids noted below will be considered as Spinosaurus, based on Ibrahim et al., (2020) ("Taphonomy," "Spinosauridae") and Smyth et al., (2020).

Links:
Ibrahim et al., (2020) ("Taphonomy," "Spinosauridae"):
https://zookeys.pensoft.net/article/47517/element/7/0/deltadromeus/
Smyth et al., (2020):

5. MNHM SAM 124:
Rostrum:
1. 63 cm. (My measurement from Taquet and Russell, 1998, pg. 349, "C")
2. 86 cm (reconstructed). (My measurement from Dal Sasso et al., 2005, pg. 894)
3. **62.5 cm (at best) (Measured on 3/15/21 in Ibrahim et al., 2020(a), Figure 123)
Maxilla to Antorbital Fossa: 46 cm. (Measured on 4/26/20 in Dal Sasso et al., 2005, Figure 4, "A")
*Premaxilla to 7th aveoli: 21 cm. (Measured on 4/26/20 in Ibrahim et al., 2020, Figure 123, "D")
*Premaxilla to Maxilla: 26 cm (Measured on 3/15/21 in Ibrahim et al., 2020(a), Figure 123 D).
Premaxilla: 64 cm (reconstructed) (Measured on 3/15/21 in Dal Sasso et al., 2005, p. 894).

Rostum (Ibrahim et al., 2020(a), Figure 123):
Suchomimus: 
Skull: 119.0 cm.
Full Rostrum: 78 cm.
Maxilla to Antorbital Fossa: 39.5 cm. 
Premaxilla to 7th aveoli/tooth: 12 cm.
Premaxilla: 33 cm. 
Premaxilla to Maxilla: 12.5 cm.
Length: 10 meters.

Rostrum:
78 - 62.5 = 15.
15.5/78*100 = 19.9% decrease.
10 m - 19.9% = 26 feet (8.0 meters).

Premaxilla:
64 - 33 = 31.
31/33*100 = 93.4% increase.
10 m + 93.4% = 19.3 meters.

Maxilla to Antorbital Fossa:
39.5 - 46 = 6.5.
6.5/39.5*100 = 16.5% increase.
10 m + 16.5% = 38 feet (11.7 meters).

*Premaxilla to Maxilla:
MSNM V4047:
Premaxilla to Maxilla: 30 cm.
Body: 14.0 meters.

 26 - 30 = 4.
4/30*100 = 13.3% decrease.
14.0 m - 13.3% = 40 feet (12.1 meters).

It appears that the estimates i've obtained from Dal Sasso et al., (2005) aren't entirely accurate, so I'll go by what I've measured from Ibrahim et al., (2020)(a). The premaxilla to maxilla length seems alright.

MNHM SAM 124's Total Length: 40 feet (12.1 meters).

Links:
Taquet and Russell (1998):
Dal Sasso et al., (2005):
Sales and Schultz (2017):

6. MSNM V4047:
Size estimate: 12.5-18 meters. (Dal Sasso et al., 2005) (Therrien and Henderson, 2007) (Ibrahim et al., 2014) (Lakin and Longrich, 2018)(Henderson, 2018)

Rostrum Size:
-101.0 cm. (My measurement from Dal Sasso et al., 2005, pg. 890 and 894).
Premaxilla to Maxilla: 35 cm. (My Measurement in Dal Sasso et al., 2005) (My measurement in Hendrickx et al., 2016)
Maxilla to Antorbital Fossa: 66 cm (at best). (Measured on 4/26/20 in Dal Sasso et al., 2005, Figure 1, Drawing, 2nd One) (Ibrahim et al., 2020, Figure 129, "B")
Premaxilla up to 7th aveoli: 34 cm. (Measured on 4/26/20 in Dal Sasso et al., 2005, Figure 1, Drawing, 3rd one).

MSNM V4047 Rostrum (Dal Sasso et al., 2005, Figure 1). Scale bar is 20 cm:
Spinosaurus Specimen MNHM SAM 124:
Rostrum: 86 cm.
Maxilla to Antorbital Fossa: 46 cm.
Premaxilla to 7th aveoli: 21 cm.
Body: 11.7 meters. 

Rostrum:
101 - 86 = 15.
15/86*100 = 17.4% increase.
11.7 m + 17.4% = 45 feet (13.7 meters).

Maxilla to Antorbital Fossa:
66 - 46 = 20.
20/46*100 = 43.5% increase.
11.7 m + 43.5% = 55 feet (16.8 meters).

*Update (3/14-16/21): Skull Reconstruction from Ibrahim et al., (2020)(a) Figure 129 (Scale bar is 40 cm):
Skull diagram (for reference) and reconstruction (Figure 129) (Scale bare is 40 cm):
Figure 129 Description:
Rostrum (Ibrahim et al., 2020(a), Figure 123) (Scale bar for A-D is 20 cm):
Rostrum Size: 99 cm (Measured on 3/15/21 in Ibrahim et a., 2020(a), Figure 123 A).
Premaxilla: 82 cm (at best) (Measured on 3/15/21 in Ibrahim et al., 2020(a), Figure 129 A).
Maxilla: 81 cm (at best) (Measured on 3/14/21 in Ibrahim et al., 2020(a), Figure 129 B).
Premaxilla to Maxilla: 30 cm (Measured on 3/15/21).
Dentary: 95 cm. (Figure 129, "B" [Below]) (Scaled up from the new specimen NHMUK VP R 16421).
Dentary Tooth Row: 68 cm (at best) (Measured on 3/20/21, Figure 129 B).

Suchomimus:
Maxilla: 59 cm.
Dentary: 67.7 cm.
Body: 10.0 meters.

Maxilla:
59 - 81 = 22.
22/59*100 = 37.3% increase.
10 m + 37.3% = 45 feet (13.7 meters).

Dentary:
95 - 67.7 = 27.3.
27.3/67.7*100 = 40.3% increase.
10 m + 40.3% = 46 feet (14.0 meters).

Update (9/14/23):
Premaxilla to Maxilla: 30 cm.

MNHM SAM 124:
Premaxilla to Maxilla: 26 cm.
Body: 12.1 meters.

26 - 30 = 4.
4/26*100 = 15.4% increase.
12.1 m + 15.4% = 46 feet (14.0 meters).

MSNM V4047's Total Length: 46 feet (14.0 meters).

Links:
Lakin and Longrich (2018) (Pg. 136 and 139):
Arden et al., (2018):
Dal Sasso et al., (2005):
Hendrickx et al., (2016):
Therrien and Henderson. 2007: 
Ibrahim et al., (2014):
 ("Supplementary Materials"):

7. MHNM.KK376:
From Hendrickx et al., 2016 (Subadult or Adult).
Skull: 0.953-1.070 mm.
Quadrate Height: 20.4 cm.

Spinosaurus Neotype FSAC-KK 11888:
Skull: 112.0 cm. (Ibrahim et al., 2014, pg. 30) (Hendrickx et al., 2016, pg. 27, Table 2)
Quadrate Height: 24 cm. (Hendrickx et al., 2016, pg. 27, Table 2)
Length: 9.4 meters.

24 - 20.4 = 3.6.
3.6/24*100 = 15% decrease.
112 cm - 15% = 95.2 cm.

I'll go with the 95.2-cm skull estimate, just to be safe.

Baryonyx Holotype BMNH R9951:
Skull: 91 cm.
Body: 7.7 meters.

95.2 - 91 = 4.2.
4.2/91*100 = 4.6% increase.
7.7 m + 4.6% = 27 feet (8.1 meters).

MHNM.KK376's Total Length: 27 feet (8.1 meters).

*Update (6/29/20):
Quadrate:
24 - 20.4 = 3.6.
3.6/24*100 = 15% decrease.
123 cm - 15% = 104.6 cm.

Shull:
Suchomimus: 
Skull: 119.0 cm.
Length: 10 meters.

119 - 104.6 = 14.4.
14.4/119*100 = 12.1% decrease.
10 m - 12.1% = 29 feet (8.8 meters).

Link:

8. BSPG 2011 I 118:
Largest specimen from Evers et al., (2015).

Cervical Vertebra 5(?) Centrum Length: 21.2 cm. (Evers et al., 2015, Table 1)

Spinosaurus Neotype FSAC-KK 11888:
Body: 10.3 meters.
Cervical Vertebrae 7 Centrum Length: 15.5 cm (Complete). (Ibrahim et al., 2015, Supplementary Materials, pg. 32)
Note: There is no C5 for the neotype. C7 is the largest cervical vertebrae given. Then again, it's not entirely certain that BSPG is a 5th cervical centrum.

21.2 - 15.5 = 5.7.
5.7/15.5*100 = 36.8% increase.
10.3 m + 36.8% = 46 feet (14.1 meters).

BSPG 2011 I 118's Total Length: 46 feet (14.1 meters).

9. "Oxalaia":
Note: Oxalaia is Spinosaurus (Smyth et al., 2020).
Body Length Estimate: 39-46 feet (12-14 meters). (Kellner et al., 2010, pg. 100)

Skull Length (Estimated): 1.350 meters. (Kellner et al., 2010, pg. 100)
Premaxilla:
-Has 7th aveoli. (Kellner et al., 2010, pg. 100 and 102, "B")
-20.1 cm. (Pg. 100)
-*My Measurement: 20.6 cm. (Measured on 4/26/20 on pg. 101, Figure 1, "B")

Suchomimus:
Skull: 119.0 cm.
Premaxilla to 7th aveoli/tooth: 12 cm. 
Length: 10 meters.

Skull:
119.0 - 135.0 = 11.
11/119*100 = 9.2% increase.
10 m + 9.2% = 36 feet (10.9 meters).

Premaxilla up to 7th aveoli:
20.6 - 12 = 8.6.
8.6/12*100 = 71.7% increase.
10.0 meters + 71.7% = 56 feet (17.2 meters).

MSNM V4047:
Premaxilla up to 7th aveoli: 34 cm.
Body: 16.8 meters.

34 - 20.6 = 13.4.
13.4/34*100 = 39.4% decrease.
16.8 m - 39.4% = 10.2 meters.

*MNHM SAM 124:
*Premaxilla to 7th aveoli: 21 cm.
Body: 12.1 meters.

20.6 - 21 = 0.4.
0.4/20.6*100 = 1.9% decrease.
12.1 m - 1.9% = 39 feet (11.9 meters).

I think 11.9 meters is more accurate.

Links:
Kellner et al., (2010):

10. 1922 X 45 ("Spinosaurus B"):
Tibia: 60 cm (2nd one) (Stromer, 1934, pg. 16).

The Irritator specimen LPP-PV-0046 had a tibia that was also 60 cm long (Aureliano et al., 2018, pg. 8 "Results": "Morphological description"), and it was 31 feet (9.3 meters) long.

"Spinosaurus B's" Total Length (Based on Irritator specimen): 31 feet (9.3 meters).

Links:
Stromer (1934) (Pg. 16):

https://www.zobodat.at/pdf/Abhandlungen-Akademie-Bayern_NF_22_0001-0079.pdf

Aureliano et al., (2018) (Pg. 8 and 12):

11. BMNH 16420:
Premaxilla to Maxilla: 23.5 cm (Measured on 3/15/21 in Ibrahim et al., 2020(a), Figure 123 B):
MNHM SAM 124:
Premaxilla to Maxilla: 26 cm.
Body: 12.1 meters.

26 - 23.5 = 2.5.
2.5/26*100 = 9.6% decrease.
12.1 m - 9.6% = 36 feet (10.9 meters).

Link:
Ibrahim et al., (2020)(a):

https://zookeys.pensoft.net/article/47517/


Spinosaurus' Total Length: 27-46 feet (8.1-14.1 meters). 
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