troodon_hunter97 Posted March 4, 2014 Share Posted March 4, 2014 4 cm tall 3 cm wide. This is from the upper Cretaceous period in the Lance Formation. Link to comment Share on other sites More sharing options...
Auspex Posted March 4, 2014 Share Posted March 4, 2014 What in the world could have caused that?! It looks like the cortical layer is missing in the area of the pattern...it seems too regular to be a pathology...color me stumped! "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
Opisthotriton Posted March 4, 2014 Share Posted March 4, 2014 It's turtle shell, the edge of the carapace (see how the texture wraps around the edge). The dimples make it a member of the Trionychoidea, and the dimples being deep and well-defined makes it a Basilemys. Closely related to soft-shelled turtles, but not soft-shelled itself. 4 Link to comment Share on other sites More sharing options...
Auspex Posted March 4, 2014 Share Posted March 4, 2014 Ah! Brava, Opisthotriton! "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
troodon_hunter97 Posted March 4, 2014 Author Share Posted March 4, 2014 Thank you Opisthotriton! Link to comment Share on other sites More sharing options...
lissa318 Posted March 4, 2014 Share Posted March 4, 2014 It's turtle shell, the edge of the carapace (see how the texture wraps around the edge). The dimples make it a member of the Trionychoidea, and the dimples being deep and well-defined makes it a Basilemys. Closely related to soft-shelled turtles, but not soft-shelled itself.Nice job on the ID! And great find troodon!!! Congrats. Link to comment Share on other sites More sharing options...
jpc Posted March 5, 2014 Share Posted March 5, 2014 W have a piece in our collection that looks similar. I have IDed it as soft-shell, but it is perplexing in that it, like yours, is really thick. I think in our database I have it labeled as "trionychid?" Th texture is soft-shell, but the thickness is weird. Link to comment Share on other sites More sharing options...
Carl Posted March 5, 2014 Share Posted March 5, 2014 I was stumped by a piece of Basilemys we collected in SD recently. Had NO idea what it was. Turns out we have a near complete shell in the AMNH collections. Very distinct ornamentation. But I don't think it's a trionychid. Link to comment Share on other sites More sharing options...
Opisthotriton Posted March 5, 2014 Share Posted March 5, 2014 Basilemys and Adocus are in Trionychoidea, just outside of true Trionychidae. The family-level name that contains Basilemys varies, depending on the age of the publication. Generally it is in the Nanhsiungchelyidae, which mostly contains Asian turtles. I'm having trouble finding a useful phylogeny, because they either just show Trionychidae taxa or just Nanhsiungchelyidae taxa, and I can't find one that shows the relationship between these two clades; do turtle authors not believe in including outgroup taxa in their cladograms? Also, the shell is thick because Basilemys is a big beast, up to a meter long. Link to comment Share on other sites More sharing options...
Carl Posted March 5, 2014 Share Posted March 5, 2014 Thanks for that! Basilemys and Adocus are in Trionychoidea, just outside of true Trionychidae. The family-level name that contains Basilemys varies, depending on the age of the publication. Generally it is in the Nanhsiungchelyidae, which mostly contains Asian turtles. I'm having trouble finding a useful phylogeny, because they either just show Trionychidae taxa or just Nanhsiungchelyidae taxa, and I can't find one that shows the relationship between these two clades; do turtle authors not believe in including outgroup taxa in their cladograms? Also, the shell is thick because Basilemys is a big beast, up to a meter long. Link to comment Share on other sites More sharing options...
jpc Posted March 6, 2014 Share Posted March 6, 2014 Basilemys, huh? Thanks both of you. I will look into it to ID our own piece. Link to comment Share on other sites More sharing options...
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