Talk:Sarcosuchus

Queries

Hi, and thanks for your contributions Mokele... but I wondered if you have a reference for that ectothermic animals can't develop muscles through exercise bit ... the article I ripped it from is non-technical, but if you're right I wonder why perfectly good scientists are taking their bite bar tests into the wild... [1]. And the lifespan reference was to the period the crocs keep growing, not their total lifespan: the growth rate in most modern crocs slows down dramatically after about 10 years, while it seems the gigantic breeds sustained a high rate of growth for a longer time... but if it caused confusion, it should be clarified. 68.81.231.127 10:30, 15 Jan 2005 (UTC)

The reference for the exercise physiology and lack of benefits of conditioning is "Effects of endurance training and captivity on activity metabolism of lizards", Garland et al. Am J Physiol Regul Integr Comp Physiol.1987; 252: 450-456. In this particular study, 2 groups of non-specialized agamid lizards were kept, one was exercised regularly, the other not. To quote from the abstract, "It is concluded that the adaptive response to endurance training, typical of mammals, does not generally occur in lizards. Moreover, levels of chronic activity that would elicit adaptive responses in mammals may be excessive for lizards and may induce pathological effects in joints and skeletal muscle."

As for why wild specimens are used, there are many reasons. First and foremost is that captivity is an un-natural state, and measurements may be skewed by things such as minor nutritional deficiencies. Additionally, many captive crocs have jaw deformities (nutrition has been implicated in this, as have several other aspects of captive care, but there's no even moderately strong consensus on it yet) which could skew tests. Furthermore, captive collections have only a limited number of crocs, often clutchmates or only from a narrow range of species and localities. Wild collection allows more diverse data gathering, reducing potentially confounding hidden variables. Plus, any excuse for fieldwork is a good one. ;-)

I also question the accuracy of the study in question, for two reasons. First, because it concludes that bite power is proportional to size. However, muscle power (including jaw muscles) is proportional to the cross-sectional area of the muscle, and, when scaling up or down in size, cross-sectional areas increase to the square of linear dimensions. Thus, if you double an animal's size, bite power should increase 4-fold, not 2-fold. However, this relationship was probably obscured by the data scatter caused by innate inter-individual variation. Also, the study in question used data from a variety of species. Obviously, a 4 foot gator will have a differnt bite pressure than a 4 foot gharial, due to differnt sizes of muscles, and different locations of muscle attachment in the species. A more accurate study would have relied exclusively on gharials (or had 3 parralell studies for gharials, false gharials and african slender snouts) and studied bite pressures from everything from hatchling to adult in large numbers, then compared differences in skull morphology. I suspect the results would have been much different.

In terms of lifespan, the comment I removed seemed to indicate that Sarcosuchus' lifespan as a whole (not just until adulthood) was significantly longer than most modern crocodilians, which does not seem to be the case. But you're right, it should be clarified. --User:Mokele

Well, it's a popular article about a scientific study not a technical paper — I'd expect errors in translation. 2,000 kg vs. 8,000 kg may be a bit high for a strict linear scaling, anyway. And have you seen the skull of S. imperator or a diagram? It's not a gharial snout, by any means. It seems to be an intermediate design between the narrow piscivores and the broad generalists.... though even the wide-mouthed C. niloticus eats more fish than anything else. The most interesting bit, which I forgot to include the first time, is that the juvenile snout is gharially slender — but it expands considerably upon maturity. I added the counter argument from Sereno's paper, and a bit more detail on classification. The whole thing really needs a copyedit, but that will have to wait for a bit. 68.81.231.127 18:37, 16 Jan 2005 (UTC)

I've read the paper, yes, but I'm unconvinced of routine large terrestrial prey, mostly because the local fish fauna included a hefty number of 6 foot long, 200 lb lobe-fins (roughly similar to the australian lungfish (Neoceratodus) in form), complete with osteoderms. I feel that, given the narrowness of the snout of both adults and juveniles, that the adult 'bulking up' is an adaptation to deal with these larger fish rather than terrestrial prey.

I agree that it's not a technical paper, but at the same time, I feel it's necessary to prevent a balanced view of the controversy surrounding this animal's feeding habits. Personally, I'm skeptical (as you can no doubt tell), mostly because of the skull shape and local sarcopterygian fauna, but I will admit that the grandiose publicity surrounding it has made me more suspicious that I otherwise would be. I feel that the most likely truth is that it's diet was primarily fish, only intermittently suplemented with smaller species of dinosaurs, as well as juveniles and carrion. Given the incredibly broad skulls of other giant crocs such as Purrasurus and Deinosuchus, I believe we can still reasonably make the link between very broad skulls being necessary for tackling large prey.

There's also the issue of bending stresses. I haven't done any biomech analysis of the skull myself, but I know that bending stress and buckling stress do not scale linearly; a large organism can't have as thin of a snout as a smaller one.

Another issue that I feel corroborates my views is the dorsoventral compression of S. imperator's snout. Such compression/reduction is needed to reduce resistance when flicking the head sideways underwater (the usual means by which crocs catch fish, as I'm sure you know). It's present in all modern crocs that are obligate piscivores (or nearly so), while "big-game hunter" crocodilians have much deeper heads.

On a totally tangential note, I noted you re-did the taxonomy. I've been meaning to learn more about the phylogeny and fossils of a broader selection of extinct croc taxa, and was wondering if you could recommend any particular papers or books on the topic? user:Mokele

Oh, I'm skeptical too... but I find the argument at least plausible, if not probable. Without something more conclusive like preserved stomach contents or tooth marks, it's just speculation. I agree that the fish-eating hypothesis should have more weight... but the article needs a reference for that opinion. (Sereno's was easier to add because I had a copy on hand.) You don't have to know of one offhand, do you?

I don't know much about biomechanics, but I'm always a little skeptical without practical tests, which is hard in extinct species. And the snap-thing isn't necessarily conclusive: C. niloticus does it too. I'd be interested to see a more depth analysis... while gigantic, sauropods have tiny necks and heads. If a croc snagged a drinking titanosaur, it might be able to kill it instantly, or at least hold on until it died and then munch on the body. But even if true, it would be opportunistic, and not the mainstay of its diet.

I'm surprised you haven't commented on Suchomimus. The comment about them fighting is absurd — even if their snouts were broader carnivores aren't MAD :). But it is in half the articles, so it needs to be mentioned. I really need to tone it down a bit more, though.

I expanded the classification mostly because the taxobox conflicted with the rest of the article... rather than force a triangular cladogram into the square hole of the Linnean taxobox, I used the old classification used in the Crocodylia article, and that just needed an explanation. I kept it general... is Deinosuchus an alligator or a croc? I'm not an expert (I'm sure you know far more about general crocodile classification and physiology than I do), but I suppose any look into ancient crocs is going to start with Benton & Clark 1988. They revised it later (1993?) with more characteristics, but the result was garbage... too many homoplasies. One of these days I'll read Schwimmer's book on Deinosuchus, and I've also heard good things about Hua's Ancient Marine Reptiles, but it's pricey.

When I get around to prettying up some of my less than brilliant prose and fixing some typos (philowhat?), I'll consolidate the argument as well... I think we've covered all the major points, but right now it reads more like a back and forth debate than an encyclopedia article :). 68.81.231.127 02:15, 17 Jan 2005 (UTC)

I was thinking that this page really should be named Sarcosuchus and not SuperCroc. SuperCroc was just a tagline for the National Geographic special, while the actual article deals with the animal. I think it would make more sense to have the redirect be for SuperCroc and not Sarcosuchus Jura 17:29, 12 April 2006 (UTC)

I agree. SuperCroc just sounds like a dumb "common name" invented to hype up the TV special. I'll go ahead and move the page to Sarcosuchus.Dinoguy2 21:23, 12 April 2006 (UTC)

I will go even further, and replace all occurances of the word SuperCroc from the article, except once, to point out its apparently "common" name. Mzyxptlk 17:33, 23 June 2007 (UTC)

Time Range

The only indicators on the page are that it says 'early cretaceous' and that it could have come into contact with suchomimus which lived at the same time. But it doesnt give the acctual millions of years that it was around for so you have to look at suchomimus's page just to get an idea, even then it isnt perfectly right. Can this be fixed by some one who knows its time range? Spinodontosaurus (talk) 16:57, 29 November 2009 (UTC)

Spinosaurus

It says in the article that Sarchosuchus was 11-12 m long, nearly as long as Spinosaurus. Spinosaurus was 17-21 m long. What's up with that? Benosaurus 02:16, 6 February 2007 (UTC)

It's proably using an outdates measurement of Spinosaurus. I'll fix it. Dinoguy2 16:25, 6 February 2007 (UTC)

Deinosauchus

In the article it says 'Deinosuchus is only known from skulls, which are smaller than that of the SuperCroc but the Deinosuchus has a broad snout.....' and it gives a measurment of ‘1.78 m’ for Sarcosuchus. In the Deinosuchus article however, it says that its skull is ‘more than 2 m ’ which statement is correct? There has always been a lot of conflicting measurements with prehistoric creatures in books and on the internet. Its always annoyed me as I’m never sure what to believe. oh well :) Steveoc 86 20:40, 16 March 2007 (UTC)

Swallowing capacity

• In proportion to its skull length, and to the animal's total length, what was the internal width between its jaw hinges? That will give some estimate of how big prey it could swallow. Anthony Appleyard (talk) 08:12, 10 June 2010 (UTC)

File:Sarcosuchus lunges at Nigel.jpg Nominated for speedy Deletion

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Size chart

I originally removed that image without explanation so I'll explain it now. I consider it outdated and having other problems, for example Purussaurus is portrayed at 12.5m but that seems like an arbitrary number since the source from where it says it got that size (Bocquentin & Melo, 2006) gives a range of 11-13m. The size of Mourasuchus is referenced to Schwimmer (2002) which does say it was 12m but offers no explanation for that. More recent papers like Salas-Gismondi et al. (2007) give a length of 7.8-11m for Purussaurus which is more realistic as the biggest skull has a snout to skull table length of "just" 1.3m, compare that to 1.6m for the biggest Sarcosuchus skull; though it is true that Sarcosuchus has a longer snout. About Mourasuchus, Langston Jr. (2008) estimates the body length of one large specimen of M. arendsi with comparable skull length to the holotype, at 6.6m, I'll quote a bit of the text:

Mourasuchus was a large crocodilian. Known skulls of M. arendsi are approximately 1m long, depending upon the definition of “total skull length” used by various authors.

Skulls around 1m long are Terminonaris/juvenile S. imperator territory, how the 12m estimate came to be, I don't know but I'm searching for the papers describing M. atopus to see if it actually has a 2m long skull. Mike.BRZ (talk) 16:54, 10 April 2013 (UTC)

I see, so it is not Sarcosuchus itself that is wrong. How about this image?[2] FunkMonk (talk) 17:00, 10 April 2013 (UTC)

Yeah, Sarcosuchus is fine in it and at 11.5m is close enough to the 11.65 given in Sereno et al. (2001). That other image portrays it at 12m which is fine but the skull looks a bit too long but I'm not sure, anyway is the other elements that bring it down, Deinosuchus hatcheri is not a valid species and the 12m+ individual portrayed there has a skull that appears to be 2m or more in length, and that is too big, not even the original reconstruction based on the Cuban crocodile was that long. BTW I've found Langston (1965) a length of the skull of Mourasuchus atopus is not given but is said to be 2.5m times smaller in abosulte terms than that of Stomatosuchus, I remember that the skull of Stomatosuchus was 2m long more or less so Mourasuchus atopus skull has to be some 80cm long at most. Mike.BRZ (talk) 17:40, 10 April 2013 (UTC)

If you have suggestions for how either image could be improved, we could ask the authors, they're both on Wikipedia still. Which one do you think would need the least modification? FunkMonk (talk) 17:48, 10 April 2013 (UTC)

Sorry for taking so long to answer, I think the first, it will probably only require resizing the silhouettes and suggestions, well, I think the two previous posts are good suggestions but I can expand on that if necessary. Mike.BRZ (talk) 19:22, 10 April 2013 (UTC)

I've notified SmokyJBJ, the author of the first image, of this discussion. FunkMonk (talk) 15:00, 11 April 2013 (UTC)

This is why I don't like size guestimates! Anyway, these should be easy fixes. I'll probably remove Mourasuchus because its under the (admittedly arbitrary) 10 m size limit for the diagram. Smokeybjb (talk) 21:12, 12 April 2013 (UTC)

Nice! And sorry for spelling your name wrong in so many ways... FunkMonk (talk) 21:18, 12 April 2013 (UTC)

Ha ha, no problem. I chose the most random user name I could think of when I started editing (my cat's name and my initials), so it's bound to be misspelled sometimes. Smokeybjb (talk) 16:25, 14 April 2013 (UTC)

Thank you! Mike.BRZ (talk) 02:26, 13 April 2013 (UTC)

How is it now? I shrunk down Purussaurus to 11 m (low end of Bocquentin & Melo, high end of Salas-Gismondi et al.) and removed Mourasuchus. I also shortened Deinosuchus to 10.5 m based on Farlow et al. (2005)[3], which estimates the total body length at 10-11 m based on skull measurements (femur measurements gave a significantly smaller length of 6-8 m, but the authors suggest Deinosuchus may have had a shorter femur length relative to body size than alligators do). Smokeybjb (talk) 16:25, 14 April 2013 (UTC)

Looks good, I hadn't realized that deinosuchus had been downsized too, I have that paper but since I only searched for mentions of Sarcosuchus in it I completely overlooked the Deinosuchus stuff. One last change though, would be to change the species of Deinosuchus, the specimen in question is housed at the Texas Memorial Museum which means that it's almost a given that it's a specimen of Deinosuchus riograndensis, as per Schwimmer (2010). I've seen other workers following that convention since it was tentatively proposed in Schwimmer (2002) and the only papers I've been able to find on Deinosuchus more recent than 2010, dealing with Texan and Mexican finds use D. riograndensis. Mike.BRZ (talk) 17:17, 14 April 2013 (UTC)

I just found out something more, another estimate for the largest Purussaurus, it's from an SVP abstract, Moreno-Bernal (2007) Size and Palaeoecology of the giant Miocene South American Crocodiles (Archosauria: Crocodylia), a more detailed version of which can be found here. Its dorsal skull length was estimated based on more complete specimens at 145.3cm and its total length calculated on regression equations for the American alligator and the saltwater crocodile; at 10.3m, a smaller specimen was also estimated with the equations for femoral measurements from Farlow et al. (2005) and the results were pretty much identical between femur and skull based estimates. Mike.BRZ (talk) 20:30, 14 April 2013 (UTC)

the "Supercroc" film

Should this be mentioned in a serious paleontology article? It would be better if this was treated as trivia, and the article on "Supercroc" linked back to this one. HammerFilmFan (talk) 03:29, 2 August 2013 (UTC)