topgems Posted December 3, 2016 Share Posted December 3, 2016 Hello all, I'm new here so don't know my way around very well. I'm looking for any information on these little sand dollars. Age, location, any help at all. All I was told is they are from Mexico. Thank you very much, Steve Link to comment Share on other sites More sharing options...
tmaier Posted December 3, 2016 Share Posted December 3, 2016 It looks like a polished fossil of the echnoid genus Oligopygus. They are found in Mexico (and USA). Can you show a photo of the underside? That can be very diagnostic. 1 Link to comment Share on other sites More sharing options...
topgems Posted December 3, 2016 Author Share Posted December 3, 2016 Hi, thank you for the help! I did flatten the back and polish the one I first posted. Here are photos of a few more that I've done nothing to. Link to comment Share on other sites More sharing options...
tmaier Posted December 3, 2016 Share Posted December 3, 2016 I'm fairly sure it is the species named Oligopygus putnami, especially if it is from Mexico. And those are polished. You might not have done it, but maybe somebody else, or nature did it? I have a lot of that genus from Florida, and that surface sure isn't natural. Link to comment Share on other sites More sharing options...
topgems Posted December 3, 2016 Author Share Posted December 3, 2016 I agree, these do kind of look tumbled but wasn't sure. I very much appreciate your help and interest. I did a quick search of Oligopygus and found some info. One site says era: Cenozoic. Does that sound right? And, another webpage here: http://www.nhm.ac.uk/our-science/data/echinoid-directory/taxa/taxon.jsp?id=727 Link to comment Share on other sites More sharing options...
tmaier Posted December 3, 2016 Share Posted December 3, 2016 The web page says "middle to late Eocene", and that is about 40 million years ago. Notice in the species list of that web page that the only known species from Mexico is the putnami. That doesn't verify that is is that species, and finding the actual documentation that gives the official description would be the ultimate test, but I don't see it available right off the bat. Link to comment Share on other sites More sharing options...
topgems Posted December 3, 2016 Author Share Posted December 3, 2016 Thank you very much for you willing to help and your expertise! It looks like you nailed it from the start. I really appreciate the help. Link to comment Share on other sites More sharing options...
tmaier Posted December 3, 2016 Share Posted December 3, 2016 No problem, it is fun to try to identify all the stuff people find. Link to comment Share on other sites More sharing options...
tmaier Posted December 3, 2016 Share Posted December 3, 2016 O, by the way, I can't reply to your PM because I'm on a low bandwidth connection. If I try to reply, it floods my modem out. Thank you for the offer, but I've got a lot of echnoids already. Link to comment Share on other sites More sharing options...
topgems Posted December 3, 2016 Author Share Posted December 3, 2016 OK, thanks again. Nice to "meet" you. Link to comment Share on other sites More sharing options...
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