tag:blogger.com,1999:blog-4989966954446423670.post7059357875883577131..comments2024-03-02T00:44:55.128-08:00Comments on Pleiotropy: The rare footed snake from ChinaBjørn Østmanhttp://www.blogger.com/profile/08859177313382114917noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-4989966954446423670.post-3727246874982662042009-09-17T02:04:03.062-07:002009-09-17T02:04:03.062-07:00Sorry, but that is very definitely the leg of a li...Sorry, but that is very definitely the leg of a lizard consumed by the snake. First, note that there is a very obvious bulge along the body, and the leg is in the right place to be the forelimb of that bulge. Note also that the soles of its foot face towards the head of the snake, which is what you expect from a prey item eaten head first.<br /><br />How it came to protrude through the body wall I don't know - either because the lizard was eaten alive and ruptured the body wall through its struggles (possible but unlikely - although I am not sure what that snake is or what its foraging methods are), or, more likely, the body ruptured when the snake was clubbed to death. This is the sort of thing you can sometimes see in roadkilled snakes. <br /><br />If it were an atavism, you would expect the leg to have grown in the "correct" place, namely the pectoral girdle (much further forward, and very unlikely, since no snake has a remnant of one), or, more likely, from the pelvic girdle, at the base of the tail, much further back. It certainly would not have grown at midbody, out of the stomach. Note that in the tailed child, the tail is in the anatomically correct position.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-4989966954446423670.post-62562321093263851302009-09-16T09:42:43.141-07:002009-09-16T09:42:43.141-07:00That's an interesting idea. It doesn't loo...That's an interesting idea. It doesn't look like it could be a leg of a lizard from the inside to me, but at least an autopsy will settle that question. I did notice the swollen body, though...<br /><br />Hopefully we'll hear from that autopsy soon.Bjørn Østmanhttps://www.blogger.com/profile/08859177313382114917noreply@blogger.comtag:blogger.com,1999:blog-4989966954446423670.post-21344857806269377962009-09-16T05:55:55.331-07:002009-09-16T05:55:55.331-07:00There was also a discussion in germany (schlangeng...There was also a discussion in germany (schlangengrube.de) about this case, with many people assuming that the snake ate a lizard and a prey foot poked through the body wall. This explains both the strange position and the swollen snake body.<br /><br />Concerning atavisms, I'd not expect a forelimb to look that well at all (AFAIK forelimbs did not shrink gradually during evolution, but were switched off suddenly very long ago (maybe something with Hox genes), whereas hindlimbs *did* shrink). So the genes controlling the details (fingers, joints etc.) of the limbs should be rather obliterated by mutations and dysfunctional after 1e8 years sitting around unused and unselected. But being just a physicist, I might be wrong.Ralf Muschallhttps://www.blogger.com/profile/04261178237250734174noreply@blogger.com