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Post by theropod on Oct 12, 2014 15:32:51 GMT 5
Ibrahim, Nizar; Sereno, Paul C.; Dal Sasso, Christiano; Maganuco, Simone; Fabbri, Matteo; Martill, David M.; Zouhri, Samir; Myhrvold, Nathan P.; Iurino, Dawid A.: Semiaquatic Adaptions in a Giant Predatory Dinosaur. Science, Vol. 345 (2014); No. 6204; pp. 1613-1616: www.jplegacy.org/downloads/misc/spinosaurus.pdfData Supplement: www.sciencemag.org/content/suppl/2014/09/10/science.1258750.DC1/Ibrahim.SM.pdfAbout that free access thing, it does work, but not with all volumes. You have to click on the journal in the site blaze linked, and it will give you an overview to the volumes and issues. You can access those that have the green square next to it, if you click on them it will show you a list of papers reading "Free access". I would recommend that we all look through the available material and post particularly interesting stuff here, BEFORE THE 30TH OF NOVEMBER! |
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Post by creature386 on Oct 12, 2014 16:01:16 GMT 5
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Post by Infinity Blade on Oct 19, 2014 5:57:49 GMT 5
Read the paper theropod sent me. It was certainly interesting, though I disagree with some of their conclusions and some stuff is outdated (Deinocheirus & Therizinosaurus are presumed carnivorous even though they acknowledged this could change, which it did).
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Post by creature386 on Oct 19, 2014 16:18:35 GMT 5
I looked a bit at the first page on JSTOR and it looks like some of their conclusions are similar to what se speculated before on carnivora, like this:
Interestingly, theropods parallel canids more so than felids in cranial proportions, and all theropods appear to have had weaker jaws than carnivorans.
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Post by theropod on Oct 19, 2014 16:39:43 GMT 5
That’s probably also the reason why the bite force estimate in Meers (2002) was so horribly flawed. It used a regression primarily composed of carnivorans, with a few crocodilians and turtles and a small varanid.
I.e. all the larger predators in there were also those that had relatively strong bite forces (large carnivorans and crocodilians). But an animal that’s one order of magnitude bigger cannot just be expected to follow the same trend of increasing bite force compared to extant large predators that those follow relative to smaller ones, let alone compared to smaller animals just not adapted for strong bite forces.
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Post by Infinity Blade on Oct 19, 2014 18:18:34 GMT 5
I can definitely see the parallels between theropods and canids (comparatively large heads & more or less adapted to chase prey). Though, I did disagree that the forelimbs played little to no role in predation (unless you were referring to something like a tyrannosaurid or abelisaurid), but that was pretty much the one similarity you could find with cats (along with perhaps the inability to grapple with the mouth well, as it doesn't appear as if most theropods had particularly strong jaws, teeth, or skulls, rather the opposite IIRC).
As for jaw strength, I can see this as true for most theropods, but even tyrannosaurids?
As for "shoehorning theropods into cat-like, dog-like, or hyena-like groups", I do think some theropods can be seen as more cat-like or dog-like (ex: tyrannosaurids are really canid or hyaenid-like for theropods IMO).
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Post by theropod on Oct 20, 2014 1:25:48 GMT 5
I do think most Carnosaurs are best analogised as varanid-like (admittedly a very rough category, just like the others).
There is no carnivoran analogy for all theropods (dromaeosaurs are raptor-like, spinosaurs are crocodile-like but with those forelimb claws rather somewhere between raptors and monitors), although I would tend to agree Tyrannosaurids are canid or hyaenid like. There are no truly cat-like theropods, at best you find a single character (such as tooth shape) somewhere, but overall they are certainly unsuitable as a proxy for ecomorphology.
And of course "shoehorning theropods" into such categories and analogies is bound to fail miserably in the end, they represent a mix of characters, at best superficially or very slightly more comparable to one extant predator than to another.
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Post by creature386 on Oct 20, 2014 16:05:35 GMT 5
Just asking, which theropods do you think come closest to cats? Droms?
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Post by theropod on Oct 20, 2014 19:22:40 GMT 5
If I had to name one group, probably droms, yes. They appear to have had the greatest emphasis on grappling with their limbs, although they did it differently from cats.
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Post by creature386 on Oct 20, 2014 21:10:48 GMT 5
Since you have the full paper, did they give examples when they mentioned something about "cat-like".
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Post by theropod on Oct 20, 2014 21:49:08 GMT 5
I haven’t come round to read all of it yet (it’s a very busy week for me), but I’ve sent it to you so you can see for yourself.
I’m sorry, I should have thought of that immediately.
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Post by creature386 on Oct 20, 2014 22:05:39 GMT 5
No problem, I was if anything happy that I didn't even have to ask.  |
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Post by Infinity Blade on Oct 21, 2014 0:13:50 GMT 5
They categorized theropods into two groups; "head-hunters" and "grappler/slashers" where dromaeosaurids fit the latter group best of all the theropods. They did however say that there was little to no evidence of cat-like theropods in their sample.
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Post by creature386 on Oct 21, 2014 0:18:16 GMT 5
Well, I am now able to look for myself, but still thank you for reducing my work.
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Post by Infinity Blade on Oct 21, 2014 5:05:14 GMT 5
You're welcome.
I too was thinking dromaeosaurids are the theropods closest to felids, but I still acknowledged this was only a very, very rough comparison (they don't grapple the same way, they don't use the same apparatus to actually kill with).
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