Tony Eaton Posted August 5, 2010 Share Posted August 5, 2010 With temperatures >105 F here in Texas it is too hot to fossil hunt even at night or in the morning. I did manage to hit the library and look at some articles. I am trying to ID some "older" Squalicorax teeth. These are from the basal Tarrant formation in North Texas. I believe this is middle Cenomanian (no Conlinoceras tarrantense ammonites here, probably younger). After reading on elasmo.com that S. curvatus is a nomen dubium and S. sp. is now named I knew I needed to find the source article. Too, before researching I could see some clear differences between the two "older" species I had found. http://www.elasmo.com/genera/genera.html#cret ANACORACID SHARKS FROM THE ALBIAN (LOWER CRETACEOUS) PAWPAW SHALE OF TEXAS by MIKAEL SIVERSON http://www3.interscience.wiley.com/journal/118531977/abstract?CRETRY=1&SRETRY=0 These teeth are quite a bit younger than Albian cited in the article. Here is a close up of what I think resembles S. pawpawensis. This is due to very slight serrations combined with a generally porous root and a fairly tall dental band. I think this tooth has a resemblance to S. baharijensis. This is due to the bigger serrations and the high dental band and put simply the "humped back". Here are more teeth, with the above two pictures at the end of each row. The top row resembles baharijensis. (third tooth from left could be affinity of S. priscoserratus?) The second row has an affinity to S. pawpawensis. The lower row has an affinity to S. falcatus (different that the younger falcatus I find). Most teeth did not have serrations. It was not easy to find a pattern on how porous the roots are (priscoserratus should have more solid roots along with a more elongate crown) Link to comment Share on other sites More sharing options...
Sharks of SC Posted August 5, 2010 Share Posted August 5, 2010 Im sorry, Im pretty umfamiliar with these teeth, but I think they're very attractive...Its amazing how similar to miocene thresher shark teeth they look. COOL finds! CBK Link to comment Share on other sites More sharing options...
Tony Eaton Posted August 6, 2010 Author Share Posted August 6, 2010 Thanks CKB! I agree it is funny how similar they look to Miocene thresher sharks, although the literature explains that they are probably not closely related if I'm not mistaken. I'm really curious of anyone's opinion good or bad LOL (although I have seen a few posts from people that obviously know more about this shark genus than me and probably at least have S. baharijensis from some part of the world). Squalicorax is probably the most common species to find anywhere in Cretaceous Texas, but as I study it is proof that abundance doesn't equal well studied. Link to comment Share on other sites More sharing options...
fossilsofnj Posted August 8, 2010 Share Posted August 8, 2010 Tony, Take at look at this website on Squalicorax; http://www.patricksharkteeth.com/ I’m sure you and Patrick can really get into a detailed discussion on the subject. John It's good sportsmanship to not pick up lost golf balls while they are still rolling. - Mark Twain Link to comment Share on other sites More sharing options...
Tony Eaton Posted July 28, 2011 Author Share Posted July 28, 2011 Better pictures of Squalicorax baharijensis or something close to it. Link to comment Share on other sites More sharing options...
cowsharks Posted July 28, 2011 Share Posted July 28, 2011 Better pictures of Squalicorax baharijensis or something close to it. i've always felt that Squalicorax teeth superficially resemble those of Tiger sharks. For example, look at your pic#4; that tooth looks so similar to G. contortus (without the twisted crown). Nice teeth! Daryl. Link to comment Share on other sites More sharing options...
Tony Eaton Posted July 28, 2011 Author Share Posted July 28, 2011 (edited) Looked at some of the G. contortus and they are similar! One interpretation of Squalicorax I had in my heaad was that there is a study progression from Squalicorax sp. to S. curvatus, to falcatus, to kaupi, then pristodontus. Lately there has been a lot of revision and new species named and it is getting more difficult to ID these teeth ;-) . Edited July 28, 2011 by Tony Eaton Link to comment Share on other sites More sharing options...
Paleoc Posted July 28, 2011 Share Posted July 28, 2011 Looked at some of the G. contortus and they are similar! One interpretation of Squalicorax I had in my heaad was that there is a study progression from Squalicorax sp. to S. curvatus, to falcatus, to kaupi, then pristodontus. Lately there has been a lot of revision and new species named and it is getting more difficult to ID these teeth ;-) . It is now turning out that there were multiple Squalicorax species living at the same time similar to Carcharhinus today. Link to comment Share on other sites More sharing options...
Tony Eaton Posted July 29, 2011 Author Share Posted July 29, 2011 (edited) On further review from what I had collected at this site (around the Eagle Ford / Woodbine contact) these anterior (sympheseal?) teeth are dramatically different than the "curvatus" symphesal that I'm attaching last. Pretty good evidence there were at least 3 fairly large Anacoracid sharks swimming around the same time and place. Edited July 29, 2011 by Tony Eaton Link to comment Share on other sites More sharing options...
Tony Eaton Posted July 29, 2011 Author Share Posted July 29, 2011 And to round out the flavors of Anacoracidae at this particular site, a beat up and relatively large (5mm) Microcorax crassus or something that compares favorably to it. Link to comment Share on other sites More sharing options...
bt4 Posted July 29, 2011 Share Posted July 29, 2011 The first image looks like falcatus--though more like the teeth from the Atco (Austin Chalk overlaying the Eagle Ford group) than the Eagle Ford teeth. The tooth with the darker crown does resemble pawpawensis, similar to material I've seen from Tarrant Co. But that would present a conundrum, since that is much older than the Eagle Ford deposits. If I remember the Dallas Co. stratigraphy, The Eagle Ford deposits date back about 90 million years, overlaying the Woodbine Group. The Pawpaw Formation I think is somewhere around the Albian Stage of the Cretaceous putting the age at somewhere around 112 million years ago. Link to comment Share on other sites More sharing options...
Tony Eaton Posted July 31, 2011 Author Share Posted July 31, 2011 The first image looks like falcatus--though more like the teeth from the Atco (Austin Chalk overlaying the Eagle Ford group) than the Eagle Ford teeth. The tooth with the darker crown does resemble pawpawensis, similar to material I've seen from Tarrant Co. But that would present a conundrum, since that is much older than the Eagle Ford deposits. If I remember the Dallas Co. stratigraphy, The Eagle Ford deposits date back about 90 million years, overlaying the Woodbine Group. The Pawpaw Formation I think is somewhere around the Albian Stage of the Cretaceous putting the age at somewhere around 112 million years ago. Thanks for the input and suggestions bt4. I agree the first and perhaps others are a bit more "falcatus" like. I have a fair amount of middle Turonian (Kamp Ranch) teeth to compare against as well as from the Atco. Maybe I'll put together some sort of comparison thread on this forum at some point. I guess if the heat continues I'll continue to have more time to analyze what I've found. There is a publication that cites pawpawensis from this timeframe from Canada if memory serves correct. http://paperfeed.org/node/317095 Perhaps if not pawpawensis the first tooth pictured in my last post with the slight crown and slight serrations is some undescribed member of "Palaeoanacorax" as described in this paper. Link to comment Share on other sites More sharing options...
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