RyanNREMTP Posted August 24, 2014 Share Posted August 24, 2014 Very cool find though. Link to comment Share on other sites More sharing options...
DE&i Posted August 24, 2014 Share Posted August 24, 2014 There's some great references to cretaceous turtle found at Hastings here at this link. http://www.geo.uni-tuebingen.de/fileadmin/website/arbeitsbereich/palaeo/biogeologie/Images/Joyce_Publications/37__Joyce_et_al.__Helochelydra__reduced.pdf Regards, Darren. Regards.....D&E&i The only certainty with fossil hunting is the uncertainty. https://lnk.bio/Darren.Withers Link to comment Share on other sites More sharing options...
PFOOLEY Posted August 24, 2014 Share Posted August 24, 2014 So the 'bottom' surface is a mold of a plasteron's inner surface? Yes...both the carapace and plastron are gone...you are seeing the mold of the inside of a small turtle's shell. 1 "I am glad I shall never be young without wild country to be young in. Of what avail are forty freedoms without a blank spot on the map?" ~Aldo Leopold (1887-1948) New Mexico Museum of Natural History Bulletins Link to comment Share on other sites More sharing options...
BobWill Posted August 24, 2014 Share Posted August 24, 2014 The furrows crossing the width were presumably where the ribs were. Now worn away. I think the ribs on a turtle are flattened out to form the shell. The furrows probably mark the divisions between the shell sections. Link to comment Share on other sites More sharing options...
BobWill Posted August 24, 2014 Share Posted August 24, 2014 So the 'bottom' surface is a mold of a plasteron's inner surface? That could explain why fosilized6s thought the bottom shell looked too small. Link to comment Share on other sites More sharing options...
tmaier Posted August 25, 2014 Share Posted August 25, 2014 OK after looking at turtle carapaces for more than I really would like to ... It seems to have the right number of "ribs". It seems the angle of the rib bones at the posterior are too perpendicular to the spine. So I'm still undecided. http://scienceblogs.com/notrocketscience/2009/07/09/how-the-turtle-got-its-shell-through-skeletal-shifts-and-mus/ http://courses.washington.edu/vertebra/452/photos/diapsids/turtle_photos.htm Link to comment Share on other sites More sharing options...
PFOOLEY Posted August 25, 2014 Share Posted August 25, 2014 Here is a great example (see figure 2). 1 "I am glad I shall never be young without wild country to be young in. Of what avail are forty freedoms without a blank spot on the map?" ~Aldo Leopold (1887-1948) New Mexico Museum of Natural History Bulletins Link to comment Share on other sites More sharing options...
JohnJ Posted August 25, 2014 Share Posted August 25, 2014 Here is a great example (see figure 2). Excellent reference, Mike. The human mind has the ability to believe anything is true. - JJ Link to comment Share on other sites More sharing options...
tmaier Posted August 25, 2014 Share Posted August 25, 2014 I'm sold on turtle now. Figure 2-C and for the "belly button" Figure 2-F Link to comment Share on other sites More sharing options...
piranha Posted August 25, 2014 Share Posted August 25, 2014 I don't have a clue on this one, but thought everyone would like to see this Wealden turtle. It's an interpretive drawing of the carapace in internal aspect of: Hylaeochelys latiscutata. Milner, A.R. (2013) Rediscovery of the Carapace of the Lost Holotype of the Purbeck Turtle Chelone obovata Owen 1842. In: Morphology and Evolution of Turtles (pp. 173-178). Springer Scientific Publishing, 577 pp. Link to comment Share on other sites More sharing options...
Gideon Posted August 25, 2014 Author Share Posted August 25, 2014 Pfooley....Figures 2 C & F look about as close as you could get it. Thanks so much to you guys for the help......I don't know what amateurs like me did before the internet! Link to comment Share on other sites More sharing options...
JohnJ Posted August 25, 2014 Share Posted August 25, 2014 I'm sold on turtle now. Figure 2-C and for the "belly button" Figure 2-F I was practically sold from the first post, but you know how some of these IDs go.... The references and local geology have me convinced it's an internal mold of a turtle (maybe with other bones locked inside). Great find. The human mind has the ability to believe anything is true. - JJ Link to comment Share on other sites More sharing options...
tmaier Posted August 25, 2014 Share Posted August 25, 2014 It's really fun to see all these new finds, it's almost like a global fossil hunt without leaving the keyboard. but the restriction of only having a few fuzzy photos can be frustrating. Especially when a thread goes on and on like this based on ambiguity of the photos. This would have ended long ago if the fossil was in each person's hands. Link to comment Share on other sites More sharing options...
RichW9090 Posted August 25, 2014 Share Posted August 25, 2014 I'm with Auspex on this one - I don't think it is a turtle steinkern. The plural of "anecdote" is not "evidence". Link to comment Share on other sites More sharing options...
tmaier Posted August 25, 2014 Share Posted August 25, 2014 But why? Do you see anything anatomically incorrect? Link to comment Share on other sites More sharing options...
JohnJ Posted August 25, 2014 Share Posted August 25, 2014 I'm with Auspex on this one - I don't think it is a turtle steinkern. Rich, this thing shares the crude appearance of ribs and a siphuncle with an ammonite. But, those characteristics on this find don't fit typical ammonite morphology. The ribs are too straight and there is no evidence of sutures, or chambers. Given its shape, I would expect more ammonite features to be present on the flat side. The human mind has the ability to believe anything is true. - JJ Link to comment Share on other sites More sharing options...
tmaier Posted August 25, 2014 Share Posted August 25, 2014 The original poster mentioned "bone". That seems to be the deciding factor. I'd like to see a closeup. Link to comment Share on other sites More sharing options...
jpc Posted August 25, 2014 Share Posted August 25, 2014 (edited) This rarely happens... Auspex and Richw are so often right on this forum, but I will respectfully disagree with both of them. I have seen more than my share of turtle steinkerns and that is exactly what this is. The divots in the top are where the vert used to be. The grooves running from the center down to the outside edge is where the ribs were. In life the ribs are fused to the inside of each costal plate. In a mold, they leave a groove. No siphuncle there. Excellent find, by the way. Edited August 25, 2014 by jpc 1 Link to comment Share on other sites More sharing options...
jpc Posted August 25, 2014 Share Posted August 25, 2014 (edited) On the bottom view you can see there is still some bone where there were struts joining the carapace to the plastron. Edited August 25, 2014 by jpc 1 Link to comment Share on other sites More sharing options...
Auspex Posted August 25, 2014 Share Posted August 25, 2014 I'm all-in on turtle steinkern now; thanks, Mike, and everyone who patiently voiced their observations and backed them with compelling information. I'm a slow study sometimes... "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...
RichW9090 Posted August 25, 2014 Share Posted August 25, 2014 (edited) One way, short of examining it, would be to pour some alginate or other "soft" molding material on it, let it gel, then remove it to provide a positive cast. Coat that with something opaque, then photograph it. One problem I have is that given the size and shape of this, if it were a turtle, it would be a very young one, which hadn't unrolled completely yet from the egg compression. In very young turtles, the carapace isn't nearly as well ossified as this would appear to be. If it is a turtle, it certainly is an exciting find. I'm just not there yet. Call me "Thomas". Rich Edited August 25, 2014 by RichW9090 The plural of "anecdote" is not "evidence". Link to comment Share on other sites More sharing options...
Auspex Posted August 25, 2014 Share Posted August 25, 2014 Rich, "Thomas" is an old acquaintance of mine, of whom I am rather fond "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...
PFOOLEY Posted August 25, 2014 Share Posted August 25, 2014 Well, Thomas...I can't seem to find many more references to persuade you. Nandomas posted this White River turtle steinkern... ...in his report, Two Eggs - Sunny Side Up . 1 "I am glad I shall never be young without wild country to be young in. Of what avail are forty freedoms without a blank spot on the map?" ~Aldo Leopold (1887-1948) New Mexico Museum of Natural History Bulletins Link to comment Share on other sites More sharing options...
RichW9090 Posted August 25, 2014 Share Posted August 25, 2014 (edited) Well, shucks...... Edited August 25, 2014 by RichW9090 The plural of "anecdote" is not "evidence". Link to comment Share on other sites More sharing options...
Auspex Posted August 25, 2014 Share Posted August 25, 2014 "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...
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