readinghiker Posted January 25, 2015 Share Posted January 25, 2015 From south of Cabezon, New Mexico (possible Tocito formation), this shark has me baffled. It was the only tooth like it in 5000 fossils from the site. The lateral ridges are serrated, and the cusp is lingually oriented. The first thought was a symphesial tooth from a squalicorax, but these teeth (as far as I know) don't have the lateral ridges. Also, the root, weathered as it is, doesn't have the shape of a squalicorax. Any help would be greatly appreciated! Randy Link to comment Share on other sites More sharing options...
enoscrawler Posted January 25, 2015 Share Posted January 25, 2015 Wow I'm going to follow this one im no tooth expert but that doesn't look common Link to comment Share on other sites More sharing options...
FossilDAWG Posted January 25, 2015 Share Posted January 25, 2015 I'm reminded of a nurse shark (Nebrius), though those are Paleogene not Cretaceous and the central large cusp is not as prominent in Nebrius as in your specimen. Don Link to comment Share on other sites More sharing options...
siteseer Posted January 25, 2015 Share Posted January 25, 2015 Don, I was thinking that too but didn't like the cusp for that either. It also looks like a Carcharhinus tooth but it appears in the Late Eocene at the earliest. It could be an oddball nurse shark but I would guess some unusual early carcharhiniform shark similar in tooth form to Galeorhinus. I've seen some weird teeth come out of the Kemp Clay and Littig Fm. in Texas (though that's younger stuff). Jess I'm reminded of a nurse shark (Nebrius), though those are Paleogene not Cretaceous and the central large cusp is not as prominent in Nebrius as in your specimen. Don Link to comment Share on other sites More sharing options...
readinghiker Posted January 25, 2015 Author Share Posted January 25, 2015 Thanks for the replies so far. Here is a lateral view of the tooth. Randy Link to comment Share on other sites More sharing options...
Al Dente Posted January 26, 2015 Share Posted January 26, 2015 Is there any Maastrichtian material in the area? Cappetta lists Ginglymostoma and Nebrius as occurring in the Maastrichtian. 1 Link to comment Share on other sites More sharing options...
readinghiker Posted January 26, 2015 Author Share Posted January 26, 2015 Al Dente, Not sure if there is any Maastrichtian deposits around, I will check on the stratigraphy later on today (fossils are a passionate avocation, I have to wait until after I finish the school day to get back to the sharks). Nebrius looks like a good candidate for this tooth, although the serrations are a lot smaller than those that I have seen on the web, and the cusp is far more lingually oriented. Maybe a new species? But I appreciate your post, you have given me the first idea of what this could be, and a way to direct my research! Randy Link to comment Share on other sites More sharing options...
readinghiker Posted January 26, 2015 Author Share Posted January 26, 2015 Not sure if there ARE any Maastrichtian deposits around...I hate it when my grammar sucks on posts! Link to comment Share on other sites More sharing options...
readinghiker Posted January 26, 2015 Author Share Posted January 26, 2015 Al Dente, Just checked on the Maastrichtian, and was informed that the nearest Maastrichtian deposit is several miles away. Link to comment Share on other sites More sharing options...
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