tag:blogger.com,1999:blog-3248412803814730250.post6206413739869117539..comments2024-03-17T01:48:59.504-07:00Comments on The Theropod Database Blog: Simiosaurs in Nesbitt's matrixMickey Mortimerhttp://www.blogger.com/profile/08831823442911513851noreply@blogger.comBlogger9125tag:blogger.com,1999:blog-3248412803814730250.post-36258615420085548382011-05-21T01:36:53.567-07:002011-05-21T01:36:53.567-07:00While the presence of a furcula would be theropod-...<i>While the presence of a furcula would be theropod-like, Peters' (perhaps incorrect) interpretation would have it posteroventrally concave and fused along its length to the sternum</i><br /><br />This sounds exactly like a description of an interclavicle...David Marjanovićnoreply@blogger.comtag:blogger.com,1999:blog-3248412803814730250.post-62850133225866801042011-05-10T14:51:33.459-07:002011-05-10T14:51:33.459-07:00Renesto (2000) believes that the cervicals assigne...Renesto (2000) believes that the cervicals assigned to Protoavis may come from a simiosaur. If you enter the Protoavis cervicals into Nesbitt's matrix along with the simiosaurs, do they form an unresolved polytomy within Simiosauria.Davidowhttps://www.blogger.com/profile/06099864739987549261noreply@blogger.comtag:blogger.com,1999:blog-3248412803814730250.post-31809192640076833912011-05-09T22:13:18.355-07:002011-05-09T22:13:18.355-07:00Dunno. I'll add it in, but I don't expect...Dunno. I'll add it in, but I don't expect that to resolve anything. The possible outcomes-<br /><br />Huehuecuetzpalli is a pterosauromorph/archosaur.<br />Peters reply- See, I'm right that lizards analyzed in the matrix would emerge as archosaurs.<br />My reply- The matrix lacks lepidosauromorph/archosauromorph/etc. characters so any placement is meaningless for both Huehuacuetzpalli and pterosaurs if you want to test if they're outside Archosauromorpha.<br /><br />Huehuecuetzpalli is outside Archosauriformes.<br />My reply- So lizards do emerge as basal in his matrix, giving you less reason to think pterosaurs would emerge as archosaurs if they're really lizards.<br />Peters reply- Nesbitt didn't include all of the relevent characters, and you/he coded everything differently than I would.<br />My reply- True on both points.Mickey Mortimerhttps://www.blogger.com/profile/08831823442911513851noreply@blogger.comtag:blogger.com,1999:blog-3248412803814730250.post-85509823301045556182011-05-09T19:28:52.298-07:002011-05-09T19:28:52.298-07:00Where do you think Huehuecuetzpalli would place?Where do you think Huehuecuetzpalli would place?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3248412803814730250.post-61496589543716877322011-05-09T01:07:38.724-07:002011-05-09T01:07:38.724-07:00Davidow- Peters (2000) added pterosaurs and his fo...Davidow- Peters (2000) added pterosaurs and his four key taxa to a few analyses of diapsids (Evans, 1988; Jalil, 1997; Bennett, 1996) and found them to clade with tanystropheids. I'm sure many of the characters are in Nesbitt's matrix, though I haven't checked the lists. As for Scleromochlus, that's coming soon. Gotta give the avemetatarsalians a chance, after all.<br /><br />Michal- As for Muller, good call. I meant Merck's 1997 thesis. Muller did indeed find them to be non-saurian relatives of kuehneosaurs.Mickey Mortimerhttps://www.blogger.com/profile/08831823442911513851noreply@blogger.comtag:blogger.com,1999:blog-3248412803814730250.post-69670141680755317222011-05-09T00:57:59.529-07:002011-05-09T00:57:59.529-07:00"they've also been considered (...) eurya..."they've also been considered (...) euryapsids (Muller, 2004)"<br /><br />Wow, really? Do you mean the chapter written by Johannes Müller in "Recent Advances in the Origin and Early Radiation of Vertebrates"? I admit I don't have access to this book, but reading the chapter's abstract I assumed that Müller recovered simiosaurs as sister to kuehneosaurids. Can you say something more?Michałnoreply@blogger.comtag:blogger.com,1999:blog-3248412803814730250.post-32651315750690905322011-05-08T20:10:54.171-07:002011-05-08T20:10:54.171-07:00What are the reasons Peters (2000) placed pterosau...What are the reasons Peters (2000) placed pterosaurs outside Archosauria? Are his characters viable when incorporated into Nesbitt's matrix? How does Scleromochlus affect Nesbitt's matrix?Davidowhttps://www.blogger.com/profile/06099864739987549261noreply@blogger.comtag:blogger.com,1999:blog-3248412803814730250.post-28054801082568742952011-05-08T19:22:24.046-07:002011-05-08T19:22:24.046-07:00From my site...
Olshevsky (1991) believed Longisq...From my site...<br /><br />Olshevsky (1991) believed Longisquama to be a basal theropod (or in his taxonomy, a basitheropod theropodomorph), but of his noted characters for that group, it only has "generally avian appearence of the skull" (vague and unlike basal theropods), carnivorous dentition (plesiomorphic for gnathostomes), furcula (somewhat uncertain), relatively large forelimbs with pentadactyl manus (plesiomorphic for tetrapods and not found in basal theropods), and "featherlike scales" (which is problematic, as parafeathers do not seem to be scales or necessarily homologous with feathers, and scales are not homologous with feathers in any case). While the presence of a furcula would be theropod-like, Peters' (perhaps incorrect) interpretation would have it posteroventrally concave and fused along its length to the sternum, quite unlike the condition in theropods.<br /><br />Of the theropodomorph characters he lists, carnivorous dentition is primitive for gnathostomes, while new specimens show Megalancosaurus lacks erect limbs and a reduced calcaneum. Of Olshevsky's basitheropod characters, an antorbital fenestra is primitive for archosauriforms and probably lacking in Megalancosaurus, "generally avian appearence of the skull" is vague and unlike basal theropods, relatively large forelimbs are primitive for tetrapods and unlike basal theropods, "clavicles, fused clavicles, or primitive furcula" covers every possibility and Megalancosaurus' are unfused which is primitive for tetrapods, and pentadactyl manus and pes are plesiomorphic for tetrapods and not found in basal theropods. The tarsus is not even incipiently mesotarsal and as noted above the calcaneum is not reduced. Megalancosaurus does share the presence of at least three sacral vertebrae with dinosaurs, but this is present in pterosaurs and some other taxa as well. Furthermore, the more basal Vallesaurus and Drepanosaurus only have two sacrals. While Megalancosaurus and theropods both have manus capable of grasping, in theropods digit I is angled towards II and III due to an asymmetrical metacarpal I articulation and twisted phalanx I-1, whereas in Megalancosaurus half the digits oppose the other half due merely to a lack of articulation between the metacarpals. This suggests the grasping abilities are convergent.Mickey Mortimerhttps://www.blogger.com/profile/08831823442911513851noreply@blogger.comtag:blogger.com,1999:blog-3248412803814730250.post-73900868238733194742011-05-08T19:19:46.595-07:002011-05-08T19:19:46.595-07:00I've never read Olshevsky 1991, what reasons d...I've never read Olshevsky 1991, what reasons does he give for classifying them as theropods?Bradhttps://www.blogger.com/profile/15613329277334129312noreply@blogger.com