tag:blogger.com,1999:blog-38902250.post7311294528727773027..comments2023-10-25T04:04:15.348-07:00Comments on When Pigs Fly Returns: Tracy RespondsZachhttp://www.blogger.com/profile/08692080707969333711noreply@blogger.comBlogger8125tag:blogger.com,1999:blog-38902250.post-17084127693066687302010-11-20T08:29:39.247-08:002010-11-20T08:29:39.247-08:00TLF seems to think you're arguing with him, wh...TLF seems to think you're arguing with <b>him</b>, when in fact you're arguing with <b>his paper</b>.David Marjanovićnoreply@blogger.comtag:blogger.com,1999:blog-38902250.post-50813364221815009582010-07-30T01:31:33.909-07:002010-07-30T01:31:33.909-07:00Oops, spoke too soon. Some pedal unguals in large ...Oops, spoke too soon. Some pedal unguals in large theropods, such as carcharodontosaurine allosauroids, are dorsally flattend _somewhat_. The unguals are otherwise generally identical to other allosauroid pedal unguals in morphology. Slight dorsal flattening also seems to occur in some other large theropods, as may be incipient in form in tyrannosaurids. But there's a distinction to be noted here: what actually causes "dorsal flattening" in these unguals? In some taxa, such as psittacosaurs, the lateral grooves are high and the ventrolateral and -medial corners are broad and pointed, and resemble nothing so much as ornithomimid manual unguals; the position of the grooves means that there is limited space between then on the dorsal margin of the ungual, which MIGHT simply be reduction of an arc into a "flat" aspect, whereas it may otherwise be rounded. In other words, flattening is an artefact of an abbreviated arc.Jaime A. Headdenhttp://qilong.wordpress.com/noreply@blogger.comtag:blogger.com,1999:blog-38902250.post-66413366736561039862010-07-29T22:59:08.548-07:002010-07-29T22:59:08.548-07:00Rozhdestvensky is wrong. Sorry. If this is the sou...Rozhdestvensky is wrong. Sorry. If this is the source, and no further backup on data regarding unguals in aquatic amniotes has supported this (none that I've read; I asked the above question for the purpose of seeing if this wasn't just taken from Rozhdestvensky), then I can confidently say that the shape of the dorsal surface of an ungual has NO influence on an animal's ability to swim, nor does it present in a reasonable majority of aquatic amniotes. It is lacking, for example, in terrapins, any lacertilian really, and virtually all mammals. Otters, I think, have been shown to have slightly dorsally-flattened unguals, but this is a horribly narrow exception.Jaime A. Headdenhttp://qilong.wordpress.com/noreply@blogger.comtag:blogger.com,1999:blog-38902250.post-73170209361358115292010-07-29T21:01:55.095-07:002010-07-29T21:01:55.095-07:00Flattend unguals
Rozhdestvensky, A. K., 1955. New...Flattend unguals<br /><br />Rozhdestvensky, A. K., 1955. New data on Psittacosaurus-Cretaceous ornithopods. In Questions on the geology of Asia, 2: 783-788.<br /><br />Its in Russian.Unknownhttps://www.blogger.com/profile/05478968436185821864noreply@blogger.comtag:blogger.com,1999:blog-38902250.post-54133293304500638402010-07-29T20:58:33.484-07:002010-07-29T20:58:33.484-07:00I'm also curious about the flattened unguals. ...I'm also curious about the flattened unguals. What evidence is there that this is an aquatic adaptation rather than one for say, a fossorial lifestyle as has been (IMO more convincingly) argued for Psittacosaurus?Matt Martyniukhttps://www.blogger.com/profile/04220900229537564466noreply@blogger.comtag:blogger.com,1999:blog-38902250.post-32737752646269261102010-07-29T16:28:29.355-07:002010-07-29T16:28:29.355-07:00Tracy, I don't have the paper, so I am interes...Tracy, I don't have the paper, so I am interested. You cite the dorsally flattened unguals as aquatic adaptations. What is the citation for this hypothesis?Jaime A. Headdenhttp://qilong.wordpress.com/noreply@blogger.comtag:blogger.com,1999:blog-38902250.post-25761857066073821402010-07-29T00:12:25.158-07:002010-07-29T00:12:25.158-07:00One of the things I didn't like was the editor...One of the things I didn't like was the editor wanted things taken out of the text that I thought was relavent; i.e. this was taken out about gastroliths There is another possibility in that Psittacosaurus was omnivorous and not just herbivorous. If they were omnivorous than a swimming Psittacosaurus with self-sharpening teeth could not only eat small vertebrates but also fresh water/terrestrial plants. If so then there is the possibility that the gastroliths were used in digestion and ballast. <br /><br />And a table of Psittacosaurs with gastroliths.<br /><br />Psittacosaurus mongoliensis = Protiguanodon mongoliensis OSBORN, 1923 Holotype: AMNH 6253: Fragmentary skull, dentary, and skeleton.<br />112 gastroliths. Mount Ussuk, Tsagan Nor Basin, Hovd Province, Mongolia.<br />Psittacosaurus mongoliensis SERENO, 1987 AMNH 6544: Fragmentary<br />skeleton including gastroliths Red Mesa, Artsa Bogdo basin, Ööshinn Nuur (Oshih Basin), Northern Gobi, Mongolia.<br /> Psittacosaurus sp MAYR, PETERS, PLODOWSKI, & VOGEL, 2002<br /> SMF R 4970: Nearly complete specimen with gastroliths, skin impressions and fiberial spines.<br /> Unknown, possibly from Sihetung near Beipiao City, Liaoning Province, China.<br />Psittacosaurus sp BEHRENDT, 2006 Number: Not given: Skull and skeleton. Note: Gastroliths. Western Liaoning Province, China.<br />Psittacosaurus mazongshanensis XU, 1997 Holotype: IVPP V 12165, fragmentary skull and skeleton with gastroliths. Western Liaoning Province, China.Unknownhttps://www.blogger.com/profile/05478968436185821864noreply@blogger.comtag:blogger.com,1999:blog-38902250.post-4669998171935764872010-07-28T23:04:23.081-07:002010-07-28T23:04:23.081-07:00Nice, I like it. I'll get back to your comment...Nice, I like it. I'll get back to your comments when I have more time. My response this time will be shorter. <br /><br />And as per your request, consider it done.Unknownhttps://www.blogger.com/profile/05478968436185821864noreply@blogger.com