Sharks of SC Posted December 16, 2009 Share Posted December 16, 2009 (edited) Hey Here are four makos I found today (12-15-09). I have NEVER been good at ID-ing makos and researching these today gave me a headache. The top tooth is the one that gave me the most troube Isurus retroflexus or Isurus praecursor? I know you probably cant tell from the photos, but its got double cusps. Thanks, CBK Edited December 16, 2009 by Sharks of SC Link to comment Share on other sites More sharing options...
siteseer Posted December 16, 2009 Share Posted December 16, 2009 Hey Here are four makos I found today (12-15-09). I have NEVER been good at ID-ing makos and researching these today gave me a headache. The top tooth is the one that gave me the most troube Isurus retroflexus or Isurus praecursor? I know you probably cant tell from the photos, but its got double cusps. Thanks, CBK CBK, You should look at modern I. oxyrinchus jaws, copy a photo of at least five or six jaws to give you an idea of morphological range per jaw position. Among the five you would want at least one juvenile and one large adult to give you the ontogenetic range. That should help you ID fossil desori-oxyrinchus teeth. You can start by looking at elasmo.com's oxyrinchus and I. paucus (possible modern descendant of retroflexus) jaws. I. retroflexus has a couple of distinguishing characters: an embossed root area right at the root-crown boundary; a noticeable flatness of the crown. Your tooth in question looks like a retroflexus but if you can provide photos of the lingual face and a side view, it would help. I don't have a praecursor dentition photo - don't really have a couple of solid defining characters to pass on other than "I know it when I see it." Link to comment Share on other sites More sharing options...
barefootgirl Posted December 16, 2009 Share Posted December 16, 2009 Those are all nice finds. In formal logic, a contradiction is the signal of defeat: but in the evolution of real knowledge, it marks the first step in progress toward victory. Alfred North Whithead 'Don't worry about the world coming to an end today. It's already tomorrow in Australia!' Link to comment Share on other sites More sharing options...
Sharks of SC Posted December 16, 2009 Author Share Posted December 16, 2009 Siteseer, Thanks for the info., I think this will prove far more fruitful than an google image search. I like the elasmo site...Im not sure why I don't refer to it more often. Barefoot girl, Thanks! CBK Link to comment Share on other sites More sharing options...
Northern Sharks Posted December 16, 2009 Share Posted December 16, 2009 Again, age would be the deciding factor. I.praecursor is Eocene, I.retroflexus is Miocene onward. There's no limit to what you can accomplish when you're supposed to be doing something else Link to comment Share on other sites More sharing options...
siteseer Posted December 16, 2009 Share Posted December 16, 2009 Again, age would be the deciding factor. I.praecursor is Eocene, I.retroflexus is Miocene onward. If he found it in one of the rivers, you may never know the source bed. The divers have found Late Eocene, Oligocene, Miocene, Pliocene, and Pleistocene stuff in the same rivers. Link to comment Share on other sites More sharing options...
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