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Post by theropod on Mar 23, 2017 3:18:01 GMT 5
AbstractFor 130 years, dinosaurs have been divided into two distinct clades—Ornithischia and Saurischia. Here we present a hypothesis for the phylogenetic relationships of the major dinosaurian groups that challenges the current consensus concerning early dinosaur evolution and highlights problematic aspects of current cladistic definitions. Our study has found a sister-group relationship between Ornithischia and Theropoda (united in the new clade Ornithoscelida), with Sauropodomorpha and Herrerasauridae (as the redefined Saurischia) forming its monophyletic outgroup. This new tree topology requires redefinition and rediagnosis of Dinosauria and the subsidiary dinosaurian clades. In addition, it forces re-evaluations of early dinosaur cladogenesis and character evolution, suggests that hypercarnivory was acquired independently in herrerasaurids and theropods, and offers an explanation for many of the anatomical features previously regarded as notable convergences between theropods and early ornithischians. I’ll let this pass without further comment for now, until I’ve read the study. First reaction was of course  ref: Baron, M. G., Norman, D. B. and Barrett, P. M. 2017. A new hypothesis of dinosaur relationships and early dinosaur evolution. Nature 543 (7646): 501–506. www.nature.com/nature/journal/v543/n7646/full/nature21700.html |
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Post by creature386 on Mar 23, 2017 3:48:41 GMT 5
I already saw on Holtz's facebook page that something happened to dinosaur phylogeny. I did not yet know what. I came here and was baffled. Wikipedia already reacted: en.wikipedia.org/wiki/DinosaurI am of course waiting for others to replicate the results. Using the hip shape as a homologous characteristic has long been problematic since it has been known that birds and Ornithischia evolved their hips independently. |
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Post by Infinity Blade on Mar 23, 2017 5:09:51 GMT 5
This nearly blew my mind!
All this time, theropods might actually have been more related to ornithischians than they were to sauropods (which in turn are more closely related to herrerasaurids than they are to any other dinosaur).
I'll be looking forward to any future challenges or corroborations to this view of dinosaur phylogeny.
Unrelated note. Theropod, I left a question or two in the theropod limb function thread and another on your dA page. Would you mind checking them out?
Edit: also, it now looks like 'ornithoscelidaphobia' (apparently the fear of dinosaurs) has basis from a legitimate word now (I mean, was 'ornithoscelida' really its own word before or was it just formed to create a word for the fear of dinosaurs?).
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Post by creature386 on Mar 23, 2017 15:09:11 GMT 5
The word "Ornithoscelida" was coined by T.H. Huxley in 1867. This was even before the Saurischia/Ornithischia classification.
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Post by Infinity Blade on Mar 23, 2017 16:14:50 GMT 5
I guess that answers my query.
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Post by theropod on Mar 23, 2017 17:57:05 GMT 5
Infinity BladeSorry about that. I think I haven’t checked my DA Notifications for a month or so 
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Post by Deleted on Mar 23, 2017 20:15:10 GMT 5
Regarding this, I think we may be running into a problem with a new group of crazies...
Are you guys aware of the recent SAND movement?
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Post by creature386 on Mar 23, 2017 20:39:24 GMT 5
No, what is it? Sauropods Are Not Dinosaurs?
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Post by Deleted on Mar 23, 2017 23:04:48 GMT 5
No, what is it? Sauropods Are Not Dinosaurs? Yes. They reject the redefinition of Dinosauria by Baron et al., which was necessary to stabilize it's definition, in favor of the older version because apparently, redefining clade names is so unethical to them. This would exclude Sauropodomorpha from Dinosauria, which then becomes synonymous with Ornithoscelida in their view. I kid you not, acepredator actually called the act of redefining Dinosauria a bit "unethical". |
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Post by creature386 on Mar 24, 2017 0:35:10 GMT 5
While I can understand why some people have problems with viewing birds as dinosaurs (they don't fit nicely in the popular imagination of dinosasurs), saying sauropods were no dinosaurs is outright insane. If there is one thing the average Joe knows dinosaurs for, it is the fact that they were friggin' HYOOJ!! And who is the hugest?
Now, "popular imagination" is of course no good criterion for a taxonomic definition (otherwise, we may stretch it to include Pteranodon or include blatant inconsistencies), but saying sauropods were no dinosaurs literally feels like saying the T. rex was no dinosaur.
But in order to give an actual argument instead of just feelings, definitions do not have any set of rules like nomenclature. They just allow us to assign labels to certain nodes and these nodes should at least have something to do with what is usually referred to as Dinosauria, so that not every blog entry, book or paper that calls sauropods dinosaurs has to be rewritten or deemed outdated.
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Post by creature386 on Mar 24, 2017 16:27:01 GMT 5
Homer's reaction:  |
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Post by Deleted on Mar 25, 2017 11:07:50 GMT 5
Huh, neat...
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