Troodon Posted April 20, 2017 Share Posted April 20, 2017 The family tree was announced back in February but the paper was just published. https://www.theguardian.com/science/2017/apr/19/how-we-revealed-a-new-family-tree-for-dinosaurs?CMP=share_btn_tw Abstract: For 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 Paper it's paywalls publication http://www.nature.com/nature/journal/v543/n7646/abs/nature21700.html 4 Link to comment Share on other sites More sharing options...
doushantuo Posted April 20, 2017 Share Posted April 20, 2017 Don't really want to gripe,but that's just the abstract. Knowing the publisher(S***ng**),this will remain paywalled for a couple of months,minimum Personally,i'd edit your post,to prevent people like me from getting their hopes up. Love to know which apomorphies they are using What,only 30 bucks for such a cracker? meanwhile:the supplementary data & Tim Williams's criticism But I'm uneasy about the revised definition of Saurischia, which has only one internal specifier (a theropod). Given the topology given by Baron et al., a better idea might have been to drop Saurischia altogether, rather than salvage it as the name for the new Herrerasauridae+Sauropodomorpha clade. Firstly, this rump Saurischia overturns an established tradition that Saurischia as a group should include theropods; I'd say that no Saurischia at all is better than a Saurischia sans Theropoda. Secondly, the sister clade to Ornithoscelida could simply be called Sauropodomorpha, with herrerasaurids simply considered basal sauropodomorphs; the prevailing stem-based definition of Sauropodomorpha allows for this. Instead Baron et al. re-define Sauropodomorpha to exclude herrerasaurids, such that the two are sister taxa within a 'new' Saurischia. Baron et al.'s phylogeny implies that a supinated, grasping hand is primitive for dinosaurs, and they further suggest that "the ability to grasp with the manus played an important role in early dinosaur evolution". It's an entirely reasonable hypothesis; but I'm skeptical. I lean toward the view that theropod forelimbs weren't really all that useful for grasping (especially prey capture). Like Persons & Currie (2017; dx.doi.org/10.1016/j.jtbi.2017.02.032), I suspect that the tendency to ascribe great adaptive significance to the freed hands of dinosaurs at least partly reflects our own human bias. Most Triassic theropods and herrerasaurids had short forelimbs; as Persons & Currie (2017) put it, it's "difficult to envision them grappling with any prey that could not have already been seized by the jaws". So I doubt the 'grasping' manus conferred on early dinosaurs some evolutionary edge over other archosaurs (including other bipeds). Link to comment Share on other sites More sharing options...
piranha Posted April 20, 2017 Share Posted April 20, 2017 9 minutes ago, doushantuo said: Don't really want to gripe,but that's just the abstract... Check your PM! Link to comment Share on other sites More sharing options...
doushantuo Posted April 20, 2017 Share Posted April 20, 2017 after the ruckus-rousing article,this has appeared I wouldn't be averse to having this as well Mensen die vragen,etc... just after i received a message from a higher power,this appeared when googling Lewisuchus Marsicano Link to comment Share on other sites More sharing options...
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