Functional Morphology of Animal Feeding Apparata

[Supercommunist]

Jun 16, 2023 5:28:30 GMT 5 elosha11 said:

Feb 5, 2023 0:15:35 GMT 5 Supercommunist said:

Robert Irwin measures a great white shark bite. Peak force was 14,000 newtons/

10:00

FYI, they stated the bite force was measured at 1400 newtons, not 14,000. Really big difference. Still, a fairly impressive bite for what looks to be a somewhat small female shark.

I assume they meant 14,000 and 10,000 netwons because 1,400 and 1000 newtons sounds ridiculously low for an adult mako and a crocodile.

[Infinity Blade]

Jun 16, 2023 20:31:44 GMT 5 theropod said:

Infinity Blade How big is that turtle? I don’t see a scale bar unfortunately. Anyway, I’m not sure, but even a 15 kn bite force could very well be sufficient to crush bone. That’s still similar to the largest molariform bite forces measured for Crocodylus porosus (i.e. the highest bite forces ever directly measured in anything, if I’m not mistaken), after all.

EDIT: Oh and an important bit of information I neglected to mention: The tegu bite force measurements were all taken at the tip of the jaws, so posterior bite forces would be expected to be considerably higher.

I haven't been able to find anything relevant on this particular specimen, but Allopleuron hofmanni averaged 1.4 meters in carapace length. This study I found has a graph of a sample of 92 individuals (all at least late stage juveniles to adults) ranging in carapace length from ~95-225 cm in length, but this is just a general range of lengths. In actuality, the smallest individual I found with a listed reconstructed carapace length was an adult with a 102 cm carapace; the largest one was an adult with a 265 cm carapace(!). Both are based on well defined measurements (Janssen et al., 2011).

If we assume this bitten individual was average, then its carapace would be almost the length of even Mosasaurus hoffmanni's skull (which is supposedly ~1.6 m long; Lingham-Soliar, 2004), so biting into a carapace this length is certainly nothing to sneeze at. Even at just ~1 meter long I think it would still be a very tough structure to damage for even a predator skull of this length. I know salties have very powerful bone-crushing bites, but I'm not sure it's enough to do damage to a turtle carapace this big (maybe that's got more to do with the fact that a saltie obviously can't easily bite a shell this large).

At any rate, whatever mosasaur bit this turtle was an absolute beast.

[Supercommunist]

Jun 17, 2023 2:43:49 GMT 5 Infinity Blade said:

Jun 16, 2023 20:31:44 GMT 5 theropod said:

Infinity Blade How big is that turtle? I don’t see a scale bar unfortunately. Anyway, I’m not sure, but even a 15 kn bite force could very well be sufficient to crush bone. That’s still similar to the largest molariform bite forces measured for Crocodylus porosus (i.e. the highest bite forces ever directly measured in anything, if I’m not mistaken), after all.

EDIT: Oh and an important bit of information I neglected to mention: The tegu bite force measurements were all taken at the tip of the jaws, so posterior bite forces would be expected to be considerably higher.

I haven't been able to find anything relevant on this particular specimen, but Allopleuron hofmanni averaged 1.4 meters in carapace length. This study I found has a graph of a sample of 92 individuals (all at least late stage juveniles to adults) ranging in carapace length from ~95-225 cm in length, but this is just a general range of lengths. In actuality, the smallest individual I found with a listed reconstructed carapace length was an adult with a 102 cm carapace; the largest one was an adult with a 265 cm carapace(!). Both are based on well defined measurements (Janssen et al., 2011).

If we assume this bitten individual was average, then its carapace would be almost the length of even Mosasaurus hoffmanni's skull (which is supposedly ~1.6 m long; Lingham-Soliar, 2004), so biting into a carapace this length is certainly nothing to sneeze at. Even at just ~1 meter long I think it would still be a very tough structure to damage for even a predator skull of this length. I know salties have very powerful bone-crushing bites, but I'm not sure it's enough to do damage to a turtle carapace this big (maybe that's got more to do with the fact that a saltie obviously can't easily bite a shell this large).

At any rate, whatever mosasaur bit this turtle was an absolute beast.

Here's a picture of crocodiles destroying adult seaturtle shells.



Edit: got access to the study. Here is a notable account.

On one occasion a large crocodile (estimated to be
greater than 4.5 m in length) crawled up the ascending
olive ridley track with its belly dragging on the sand until
approximately 10 m from the nesting turtle. The track
marks of the crocodile indicated that it lifted its belly off
the sand and ran the remaining distance to the nesting turtle
where the attack occurred, rather than using other common
gaits such as ‘‘high-walking’’ (Richardson et al. 2002) or
‘‘galloping’’ (Webb and Gans 1982). The severe force of
the impact was indicated by a piece of carapace, 20 cm in
diameter, thrown over 3 m from the point of impact.The
track marks indicated that the turtle broke free at one stage
but was recaptured 5 m closer to the water and then was
carried above the ground to the water

I realize the sea turtles that were killed in these accounts were considerably smaller but still that is some gnarly damage.

[Grey]

Jun 15, 2023 18:57:54 GMT 5 theropod said:

Mosasaur bite force based on durophagous lizards

This is a bit of fun more than it is hard science, mostly because I got the figures by measuring off of published figures, but it might be a tantalizing indication justifying looking into this further, and I’d be very interesting if anyone can approximately replicate my results

It’s pretty much common knowledge that tegu lizards are some of the most impressive animals for their size in terms of raw bite force, and they are pretty impressively sized compared to many other squamates, making them a potentially interesting analogue for estimating bite forces in durophagous mosasaurs. So I took a study that looked into this (Schaerlaeken et al. 2012) for Salvator merianae and Dracaena guianensis to try and figure out a way to estimate bite forces based on size parameters. Unfortunately Schaerlaeken et al. didn’t publish their dataset anywhere, nor any particularly useful summary statistics (using mean length and mean force to scale something up doesn’t really work well, because maths). So what I did was to try to get the data on the scaling of bite force and head width with SVL from their scatterplots in figures 2 and 3 (using webplotdigitizer: automeris.io/WebPlotDigitizer/).

Because I expect SVL to be less relevant across differently proportioned taxa, I then used the regressions of head width ~ svl for the respective taxa to estimate head width based on svl for each specimen in the svl-bite force dataset, and then ran a regression for the combined dataset of bite force ~ estimated head width and bite force ~ svl.

Here are the results:

All bite forces were measured in vivo and at the tip of the jaws.

I was interested in this because large, durophagous lizards like tegus are potentially some of the most suitable modern analogues for mosasaurs, specifically durophagous ones such as Globidens or Prognathodon. I would be suspicious about applying this to other forms, but I think for the awesomebro side of me (and probably other people too) Prognathodon is the most interesting taxon in this regard, as it is huge and has a massively robust skull, a good candidate for the strongest bite among mosasaurs.

So for estimating bite force, here are a two different approaches:
1) Estimating bite force for a large tegu, then  scaling up to mosasaur size isometrically based on head width

2) Allometric scaling based on  head width

So how hard does a large tegu bite? Based on my pooled regression for both taxa, a tegu with a head width of 60 mm would be expected to have a bite force of 438 N (90% CI 407–479 N). A tegu with a svl of 400 mm would be expected to bite with about 380 N (90% CI 352–411 N).

1) Isometric estimates

In a 3-dimensionally preserved skull of Prognathodon overtoni, SDSM 3393, the length is approx. 86 cm and the width 35 cm. Large Prognathodon  such as the holotype of P. currii can have a skull approx 1.4 m long and, based on measuring the figure in Christiansen and Bonde (2002), at least 55 cm wide. This is conservative, as the skull seems to be crushed and is preserved in a sort of oblique dorsolateral aspect, but is approximately consistent with what we get from scaling up P. overtoni based on skull length. P. saturator (Dortangs et al. 2002) also seems to have a similarly wide skull, but is similarly crushed. So using this to scale up:

Tegu	60 mm head width	437.6 N
Prognathodon overtoni, SDSM 3393	350 mm head width	e 14.89 kN
Prognathodon currii, HUJ. OR 100	~550 mm head width	e 36.77 kN

2) Allometric estimates

Based on head width, we can estimate bite forces for Prognathodon using the allometric tegu formula (bottom right in the plot above):

Prognathodon overtoni, SDSM 3393	350 mm head width	e 48.77 kN
Prognathodon currii, HUJ. OR 100	~550 mm head width	e 163.24 kN

So estimates diverge widely here. If the higher end is reasonable (though I think it is it is likely too liberal), this would put large Prognathodon specimens (and even mid-sized ones) among (if not as) the strongest biters ever, with bite forces potentially over 16 tons.

If the isometry assumption comes closer, then these are still impressive bite forces, even for modestly-sized skulls when compared to other giant predators.

Large T. rex specimens (Stan and Sue) and Pliosaurus kevani have both been computationally estimated at a similar bite force to the lower figure for P. currii presented here, both have skulls around 20-30 cm wider than Prognathodon. Zygophyseter was estimated computationally at less than a third of the lower estimate for Prognathodon currii, and also has a considerably wider skull than it (over 70 cm).

Even the smaller specimen still has a minimum bite force estimate of similar magnitudes to the highest bite forces recorded by Erickson et al. (2012) for saltwater crocodiles, which are as of my knowledge the highest bite forces ever actually measured. Granted, they are from a saltie likely around 5 m and 500 kg, so in all likelihood a smaller animal than a Prognathodon with an 85 cm skull would be, but they are also posterior bite forces while the Tegu figures are anterior.

So overall, I think Prognathodon definitely needs to be kept in mind when talking about massive bite forces. It would be very interesting to see more work specifically about mosasaur bite mechanics.

Refs:

Christiansen, P. and Bonde, N. 2002. A new species of gigantic mosasaur from the Late Cretaceous of Israel. Journal of Vertebrate Paleontology 22 (3): 629–644.

Dortangs, R.W., Schulp, A.S., Mulder, E.W., Jagt, J.W., Peeters, H.H. and De Graaf, D.T. 2002. A large new mosasaur from the Upper Cretaceous of The Netherlands. Netherlands Journal of Geosciences 81 (1): 1–8.

Erickson, G.M., Gignac, P.M., Steppan, S.J., Lappin, A.K., Vliet, K.A., Brueggen, J.D., Inouye, B.D., Kledzik, D. and Webb, G.J. 2012. Insights into the ecology and evolutionary success of crocodilians revealed through bite-force and tooth-pressure experimentation. PloS one 7 (3): e31781.
Erickson, G.M., Gignac, P.M., Steppan, S.J., Lappin, A.K., Vliet, K.A., Brueggen, J.D., Inouye, B.D., Kledzik, D. and Webb, G.J. 2012. Insights into the ecology and evolutionary success of crocodilians revealed through bite-force and tooth-pressure experimentation. PloS one 7 (3): e31781.

Schaerlaeken, V., Holanova, V., Boistel, R., Aerts, P., Velensky, P., Rehak, I., Andrade, D.V. and Herrel, A. 2012. Built to Bite: Feeding Kinematics, Bite Forces, and Head Shape of a Specialized Durophagous Lizard, Dracaena guianensis (Teiidae). Journal of Experimental Zoology Part A: Ecological Genetics and Physiology 317 (6): 371–381.

I think a study regarding mosasaurs bite forces is at work, clearly Prognathodon is a genus to look at.

It's not the first time I see tegu based bite forces figures suggested for mosasaurs, some Russian paleonerds worked this out less rigorously and already deduced massive bite forces for M. hoffmanni, already originally emphasised by Lingham-Soliar.

sta.sh/0pbx8899gie


Mosasaurus is not as strongly jawed as Prognathodon but with skulls possibly well exceeding 1.7 m huge figures might be expected.

Isn't P. saturator even more strongly equiped for high bite forces than P. curii ?

Thalassotitan certainly was not soft either.

[theropod]

I’m not aware of P. curii and P. saturator having been quantitatively compared. The description of P. saturator and that of P. currii came out at about the same time and neither cites the other, so even though Dortangs et al. stressed the extreme adaptations for powerful biting they observed, I don’t think they implied any comparison with P. curii in that. They seem to have similar-sized and similarly robust skulls to me, which would imply similar bite forces.

Yes, other people have used tegus for scaling mosasaur bite force. Though I’ve had (and then discarded) that plan before, it was indeed inspired by that very analysis on deviantart that you shared; or specifically, an inquiry I made below the deviation it accompanied, in the comments, trying to see how the bite force figures were estimated.
more here: www.deviantart.com/rimasuchus/art/Mosasaurus-hoffmanni-reconstruction-and-size-709870591

However I think there are numerous severe problems with that post, from lack of documentation of any of the methodology, to a very probably inflated length estimate, to errors in the mass estimation technique (assuming rectangular rather than elliptical body cross-sections), to seemingly scaling bite force based on body mass rather than cranial metrics (for which I think it would have to be demonstrated that skull-body scaling is comparable between the two, otherwise I would expect bite force to more tightly correlate with head size than postcranium size), as well as, presumably (not exactly clear since the author never explained his exact methods) using incorrect scaling from sample means.

But yes, certainly Mosasaurus hoffmanni would be very interesting. I just think that based on skull proportions it is not as easily comparable to a tegu as Prognathodon, hence I focused on the latter for now. I have no doubt it would still have had a massive bite force, but the much longer and narrower skull of Mosasaurus complicates this comparison somewhat (esp. in terms of anterior mechanical advantage, whereas Prognathodon is quite similar in terms of overall proportions (a bit more pointed in the snout, but with a similar-sized adductor chamber at the same skull width and not too much more elongated). It would of course be very interesting to see analyses specifically based on Mosasaur jaw apparata.

[Grey]

So we are potentially looking at the large Prognathodon species outclassing in raw bite force the likes of T. rex, Pliosaurus and Kronosaurus...?

Pretty sure we'll discuss this again soon enough.

[theropod]

At this point, that seems possible, yes. Certainly it should be kept in mind as a possibility to be further investigated. As tegus demonstrate, durophagous lizards are extremely impressive biters for their size. But note the vast uncertainty between the isometric scaling (which gives something roughly comparable to those taxa you mention) and the strong positive allometry in tegu lizards (which if extrapolated could make this the most powerful bite force known, but that is extrapolating very far beyond the original data at a high exponent, and thus a questionable assumption).

[Supercommunist]

I also almost forget, there was a documentary called crocodile island battlegrounds that had a lot of clips of salties preying on adult sea turtles. You can find it on youtube.

At 7:43 you can see some notable shell damage.
www.youtube.com/watch?v=S35d_eWzosw&ab_channel=VeraDrommen

[Infinity Blade]

Bite-Force Scaling across Size Classes in the Alligator Snapping Turtle (Macrochelys temminckii) and the Common Snapping Turtle (Chelydra serpentina)

Understanding feeding performance can inform feeding ecology and niche dynamics. Macrochelys temminckii (Alligator Snapping Turtle) and Chelydra serpentina (Common Snapping Turtle) are closely related, sympatric species with documented interactions. To understand ontogenetic and interspecific differences in bite performance, we measured bite force in an ontogenetic series of 62 Alligator Snapping Turtles and 33 Common Snapping Turtles. Within species, bite force positively correlated with size but scaled differently by species. Alligator Snapping Turtles produced higher maximum bite forces overall throughout ontogeny than Common Snapping Turtles, although Alligator Snapping Turtles reach significantly larger maximum sizes than Common Snapping Turtles, thereby enabling them to produce higher maximum bite forces. Differences in bite force between these species provide biomechanical context for distinctions in the ecologies of both species.

bioone.org/journals/southeastern-naturalist/volume-22/issue-sp12/058.022.0sp1228/Bite-Force-Scaling-across-Size-Classes-in-the-Alligator-Snapping/10.1656/058.022.0sp1228.short

[Infinity Blade]

So apparently Gigantopithecus blacki could bite harder at the molars than a lot of apes, except Paranthropus boisei.

Gigantopithecus blacki is hypothesized to have been capable of processing mechanically challenging foods, which likely required this species to have high dental resistance to fracture and/or large bite force. To test this hypothesis, we used two recently developed approaches to estimate absolute crown strength and bite force of the lower postcanine dentition. Sixteen Gigantopithecus mandibular permanent cheek teeth were scanned by micro-computed tomography. From virtual mesial cross-sections, we measured average enamel thickness and bi-cervical diameter to estimate absolute crown strength, and cuspal enamel thickness and dentine horn angle to estimate bite force. We compared G. blacki with a sample of extant great apes (Pan, Pongo, and Gorilla) and australopiths (Australopithecus anamensis, Australopithecus afarensis, Australopithecus africanus, Paranthropus robustus, and Paranthropus boisei). We also evaluated statistical differences in absolute crown strength and bite force between the premolars and molars for G. blacki. Results reveal that molar crown strength is absolutely greater, and molar bite force absolutely higher, in G. blacki than all other taxa except P. boisei, suggesting that G. blacki molars have exceptionally high resistance to fracture and the ability to generate exceptionally high bite force. In addition, G. blacki premolars have comparable absolute crown strength and larger bite force capabilities compared with its molars, implying possible functional specializations in premolars. The dental specialization of G. blacki could thus represent an adaptation to further facilitate the processing of mechanically challenging foods. While it is currently not possible to determine which types of foods were actually consumed by G. blacki through this study, direct evidence (e.g. dental chipping and microwear) left by the foods eaten by G. blacki could potentially lead to greater insights into its dietary ecology.

www.sciencedirect.com/science/article/abs/pii/S0047248422001737

[Amaltheus]

Not really something about bite forces but fitting the thread name. Two of my thesis chapters on temporal openings and how the adductor musculature affects skull morphology.

While most early limbed vertebrates possessed a fully-roofed dermatocranium in their temporal skull region, temporal fenestrae and excavations evolved independently at least twice in the earliest amniotes, with several different variations in shape and position of the openings. Yet, the specific drivers behind this evolution have been only barely understood. It has been mostly explained by adaptations of the feeding apparatus as a response to new functional demands in the terrestrial realm, including a rearrangement of the jaw musculature as well as changes in strain distribution. Temporal fenestrae have been retained in most extant amniotes but have also been lost again, notably in turtles. However, even turtles do not represent an optimal analog for the condition in the ancestral amniote, highlighting the necessity to examine Paleozoic fossil material. Here, we describe in detail the sutures in the dermatocranium of the Permian reptile Captorhinus aguti (Amniota, Captorhinidae) to illustrate bone integrity in an early non-fenestrated amniote skull. We reconstruct the jaw adductor musculature and discuss its relation to intracranial articulations and bone flexibility within the temporal region. Lastly, we examine whether the reconstructed cranial mechanics in C. aguti could be treated as a model for the ancestor of fenestrated amniotes. We show that C. aguti likely exhibited a reduced loading in the areas at the intersection of jugal, squamosal, and postorbital, as well as at the contact between parietal and postorbital. We argue that these “weak” areas are prone for the development of temporal openings and may be treated as the possible precursors for infratemporal and supratemporal fenestrae in early amniotes. These findings provide a good basis for future studies on other non-fenestrated taxa close to the amniote base, for example diadectomorphs or other non-diapsid reptiles.

www.frontiersin.org/articles/10.3389/fevo.2022.841784/full

One of the major questions in evolutionary vertebrate morphology is the origin and meaning of temporal skull openings in land vertebrates. Partly or fully surrounded by bones, one, two, or even three openings may evolve behind the orbit, within the ancestrally fully roofed anapsid (scutal) skull. At least ten different morphotypes can be distinguished in tetrapods with many modifications and transitions in more crownward representatives. A number of potential factors driving the emergence and differentiation of temporal openings have been proposed in the literature, but only today are proper analytical tools available to conduct traceable tests for the functional morphology underlying temporal skull constructions. In the present study, we examined the anatomical network in the skull of one representative of early amniotes, †Captorhinus aguti, which ancestrally exhibits an anapsid skull. The resulting skull modularity revealed a complex partitioning of the temporal region indicating, in its intersections, the candidate positions for potential infratemporal openings. The framework of †C. aguti was then taken as a template to model a series of potential temporal skull morphotypes in order to understand how skull openings might influence the modular composition of the amniote skull in general. We show that the original pattern of skull modularity (†C. aguti) experiences comprehensive changes by introducing one or two temporal openings in different combinations and in different places. The resulting modules in each skull model are interpreted in regard to the feeding behavior of amniotes that exhibit(ed) the respective skull morphotypes. An important finding is the alternative incorporation of the jugal and palate to different modules enforcing the importance of an integrated view on skull evolution: the temporal region cannot be understood without considering palatal anatomy. Finally, we discuss how to better reconstruct relative jaw muscle compositions in fossils by considering the modularity of the skull network. These considerations might be relevant for future biomechanical studies on skull evolution.

www.frontiersin.org/articles/10.3389/fevo.2021.799637/full

[Infinity Blade]

Jaw function of a third, but much lesser known, megalodon: Brachysuchus megalodon (Case, 1930). This phytosaur was a formidably-armed macropredator.

It is apparent that the form described as Brachysuchus megalodon was of notably different feeding habits from such forms as Leptosuchus and Mystriosuchus carolinensis. The extremely heavy bones and the relatively short symphasial region in Brachysuchus, with the powerful anterior tusks and the large posterior cutting teeth and with the evidence of greatly developed jaw muscles, are in strong contrast to the longer, lighter jaws, the weaker teeth and the less well developed jaw muscles of the other forms. The light phytosaurs with elongate jaws which permitted a very quick snap probably fed upon fish and the more softly bodied forms, while the phytosaurs of the Brachysuchus type were well equipped to capture and devour the heavily armored forms, such as other phytosaurs and the giant stegocephalians. That even such powerful jaws and strong teeth as were possessed by Brachysuchus suffered from the force necessary to crush the defensive armor of the prey, is amply attested by the deformed anterior end of the specimen described and by the injuries to the median elevation between the teeth.

[Infinity Blade]

So apparently Saurosuchus had a weaker bite than Allosaurus. But it still had a strong skull. Would like to see biomechanical modeling incorporating the neck to see how it functioned.

Functional morphology of the Triassic apex predator Saurosuchus galilei (Pseudosuchia: Loricata) and convergence with a post-Triassic theropod dinosaur

Pseudosuchian archosaurs, reptiles more closely related to crocodylians than to birds, exhibited high morphological diversity during the Triassic and are thus associated with hypotheses of high ecological diversity during this time. One example involves basal loricatans which are non-crocodylomorph pseudosuchians traditionally known as “rauisuchians.” Their large size (5–8+ m long) and morphological similarities to post-Triassic theropod dinosaurs, including dorsoventrally deep skulls and serrated dentitions, suggest basal loricatans were apex predators. However, this hypothesis does not consider functional behaviors that can influence more refined roles of predators in their environment, for example, degree of carcass utilization. Here, we apply finite element analysis to a juvenile but three-dimensionally well-preserved cranium of the basal loricatan Saurosuchus galilei to investigate its functional morphology and to compare with stress distributions from the theropod Allosaurus fragilis to assess degrees of functional convergence between Triassic and post-Triassic carnivores. We find similar stress distributions and magnitudes between the two study taxa under the same functional simulations, indicating that Saurosuchus had a somewhat strong skull and thus exhibited some degree of functional convergence with theropods. However, Saurosuchus also had a weak bite for an animal of its size (1015–1885 N) that is broadly equivalent to the bite force of modern gharials (Gavialis gangeticus). We infer that Saurosuchus potentially avoided tooth–bone interactions and consumed the softer parts of carcasses, unlike theropods and other basal loricatans. This deduced feeding mode for Saurosuchus increases the known functional diversity of basal loricatans and highlights functional differences between Triassic and post-Triassic apex predators.

[Supercommunist]

I am not sure why researchers tend to make such strange and misleading comparisons when they bring up extinct animal bite forces. Why would they compare a juvenile Saurosuchus to a gharial? Was this juvenile still a large animal overall or was it much smaller than a gharial?

I remember that one time pop science articles kept claiming that komodos have a bite force weaker than a house cat because the authors did not clarify that the komodos used in the study were small, young animals.

[theropod]

Looking at the details of such estimates is very important. The study→ in question determined physiological cross-sectional area under the assumption that the muscles were parallel-fibred and that fiber length equals muscle length, which results in much lower PCSA. Bates and Falkingham (2018) discuss this issue at length. Shorter fiber lengths and higher result in relatively higher PCSA.

Disregarding muscle architecture this way results in a bite force over twice lower, even despite considerably larger estimated muscle volumes, for the example of T. rex. Of course that is not to say that all animals necessarily have the same pennation angle or fiber length (there might be good reasons to expect relatively high or low values here, but that would require supporting reasoning on a case-by-case-basis), rather that these are unknowns and assumptions that need to be kept in mind when comparing estimates from different studies.

Aug 17, 2023 8:22:48 GMT 5 Supercommunist said:

I am not sure why researchers tend to make such strange and misleading comparisons when they bring up extinct animal bite forces. Why would they compare a juvenile Saurosuchus to a gharial? Was this juvenile still a large animal overall or was it much smaller than a gharial?

This criticism seems to be unwarranted. The skull is claimed in the paper to be similar in size to that of Allosaurus (the specimen they use for comparison is MOR 693, which is about 78 cm long), and this is consistent with their figure, based on which it is about 80 cm long (pmx-q), a measurement that’s probably accurate since this is a rendered 3D model that should have an accurate scalebar. So not only is this a large animal, it’s far larger than a normal-sized gharial.


(from figure 1 in Fawcett et al. 2023, scale bar is 10 cm)

I would agree that it is a big negligent to not explicitly list at least one or two basic measurements of the specimens that are being analyzed (such as at least some basic measure that can be used as a proxy for the specimen size, in this case that would be skull length) and I do find it a bit annoying how often I need to take standard measurements myself from some figure or 3D model (for example in Perucetus, where not a single linear measurement is listed in the description of an animal primarily noted for its size), but that’s not really affecting the accuracy, only the convenience of evaluating and reproducing the results.

---
Bates, K.T. and Falkingham, P.L. 2018. The importance of muscle architecture in biomechanical reconstructions of extinct animals: a case study using Tyrannosaurus rex. Journal of Anatomy 233 (5): 625–635.
Fawcett, M.J., Lautenschlager, S., Bestwick, J. and Butler, R.J. 2023. Functional morphology of the Triassic apex predator Saurosuchus galilei (Pseudosuchia: Loricata) and convergence with a post-Triassic theropod dinosaur. The Anatomical Record n/a (n/a).