tag:blogger.com,1999:blog-38902250.post7018502554229732645..comments2023-10-25T04:04:15.348-07:00Comments on When Pigs Fly Returns: Weekend SketchesZachhttp://www.blogger.com/profile/08692080707969333711noreply@blogger.comBlogger4125tag:blogger.com,1999:blog-38902250.post-41366869583746284372010-02-15T12:51:51.642-08:002010-02-15T12:51:51.642-08:00Well I see the "plesiosaur/pliosaur" iss...Well I see the "plesiosaur/pliosaur" issue has been adequately covered already. I'm trying to train myself away from "basal" (<a href="http://myrmecos.wordpress.com/2010/01/21/the-problem-with-basal/" rel="nofollow">see here</a>)--but <i>Utatsusaurus</i> is indeed one of the basalmost known ichthyosaurs (along with <i>Parvinatator</i> and the <i>Grippia</i>+<i>Chaohusaurus</i> group. Also, plesiosaurs sensu stricto didn't coexist with nothosaurs and pachypleurosaurs, but their likely ancestors, the pistosaurs did.Neilhttps://www.blogger.com/profile/10293693723899837239noreply@blogger.comtag:blogger.com,1999:blog-38902250.post-14355177635427971492010-02-15T11:44:35.943-08:002010-02-15T11:44:35.943-08:00Goddamnit, Andy beat me to the punch.
Robin O'...Goddamnit, Andy beat me to the punch.<br /><br />Robin O'Keefe has done the most work on this problem, indeed. The 'pliosaur' vs. 'plesiosaur' dichotomy has a lot to do with ecomorphotypes and assumptions made by pre-cladists.Nickhttps://www.blogger.com/profile/08718847558790015112noreply@blogger.comtag:blogger.com,1999:blog-38902250.post-86884126546158157122010-02-15T08:39:42.749-08:002010-02-15T08:39:42.749-08:00while i'm no expert, the two experts i've ...while i'm no expert, the two experts i've talked to on the subject (i'm a bit of a marine reptile junky) stated different but interesting opinions.<br /><br />before i state their difference in opinion, what they agreed upon was this. long and short necked plesiosaurs were never continuous groups. throughout the mesozoic any line that had one neck size was typically evolving into the other. so you ended up with a state of flip flopping every few 10-20 million years. this i find very interesting, but have never found a good paper on.<br /><br />the late Dr. Betsy Nicholls was of the opinion both families were arbitrary and all members are part of one group.<br /><br />her grad student (whose name i can't remember off the top of my head, but he works in northern alberta) thought there was some validity to the names, but there needed to be a major revision of the whole group to find new defining character. which he was certain would require the erection of several new families to cover the odd radiation seen in the group.<br /><br />i don't have any papers on the subject. i would love to read them! i did try to find them. <br /><br />sadly Dr. Nicholls grew very ill my first year at the Tyrrell, and thus was not avaliable for questions like the other curators. (i was extremely lucky, and saw her at her last public talk before her passing). i only met her former grad student once at a conference.<br /><br />let me know what you find out. this is a subject that interests me a lot too.traumadorhttps://www.blogger.com/profile/00387315561167115253noreply@blogger.comtag:blogger.com,1999:blog-38902250.post-5570814309920941652010-02-15T03:11:26.061-08:002010-02-15T03:11:26.061-08:00The work of F. Robin O'Keefe is probably most ...The work of F. Robin O'Keefe is probably most relevant to the question of "plesiosaur" vs. "pliosaur" polyphyly. Check out his pubs <a href="http://www.science.marshall.edu/okeefef/pubs.html" rel="nofollow">here</a>; the 2002 paper is most of interest.Andyhttps://www.blogger.com/profile/16171447306687358664noreply@blogger.com