dsaavedra Posted January 16 Share Posted January 16 Yesterday I found a Y-shaped bone fragment on the beach along the Calvert Cliffs in Maryland, USA (Miocene epoch, Calvert fm.). It is approximately 6.7 centimeters long, 3.1 centimeters wide at the forked end, and 1 centimeter wide at the narrow end. I have an inclination that it could be a fragment of a dolphin jaw where the lower mandibles fuse together but would like some other opinions for confirmation or a better ID. Ventral view (presumably) Dorsal view (presumably) - this side is fractured, exposing the concave interior of the bone Right lateral view (presumably) I found some photos of a living species, Pontoporia blainvillei, that is endemic to Brazil, Uruguay, and Argentina and bears a strong resemblance to my fossil. For reference, here is a high quality photo of Pontoporia blainvillei skull Holding my fossil in front of the photo suggests a good match: So does pontoporiid dolphin jaw seem like the correct ID? Is there any way to identify it further? Thanks in advance and my apologies if I left anything out - this is my first ID post. I'll be happy to provide more info/pictures if needed. 4 Link to comment Share on other sites More sharing options...
ted coulianos Posted January 17 Share Posted January 17 Correct; lower element of a dolphin rostrum. The Maryland Geological Survey Miocene text/plates list this as Priscodelphinus (?) crassanulum. The Pontoporiidae are river/estsuarine dophins with an exaggerated long rostrum and small peg-like teeth. Yours find is a very good match, as the Maryland Miocene forms seem to have occupied the same ecological niche. Attached is the plate from the MGS Miocene volume and very fragmented dolphin lower rostrum that I found in the Calvert Fm for comparison. Nice find! 2 1 1 Link to comment Share on other sites More sharing options...
trilobites_are_awesome Posted January 17 Share Posted January 17 Nice dolphin jaw! Cheers! James Link to comment Share on other sites More sharing options...
ted coulianos Posted January 17 Share Posted January 17 37 minutes ago, trilobites_are_awesome said: Nice dolphin jaw! thanks! unfortunately broken more times than a Russian promise......:) 1 Link to comment Share on other sites More sharing options...
hemipristis Posted January 17 Share Posted January 17 Very nice! 'Those who cannot remember the past are condemned to repeat it.' George Santayana Link to comment Share on other sites More sharing options...
ted coulianos Posted January 17 Share Posted January 17 (edited) Just a little follow-up: check out The Fossil Guy's website on Miocene finds. This Eurhynodelphis from the Calvert may match your find perfectly. Hope this helps. Fossilguy.com: Eurhinodelphis - The Long-Snouted Dolphin - Facts, Information, and Fossil Examples Edited January 17 by ted coulianos 1 Link to comment Share on other sites More sharing options...
shark57 Posted January 17 Share Posted January 17 Definitely a dolphin lower jaw. Unfortunately, it looks like all the characteristics used to identify it further are not present. These would include length, size of teeth or tooth sockets, spacing of teeth, etc. Almost all the Miocene dolphins would have a symphysis area that looks like this. Eurhinodelphis is now considered to be solely a European genus. The genus name for American species is Xiphiacetis, and it is the most common dolphin found in the Calvert Formation. You could take it to the Calvert Marine Museum and show it to Stephen Godfrey, but I'm pretty sure he will tell you the same thing. Link to comment Share on other sites More sharing options...
dsaavedra Posted January 17 Author Share Posted January 17 Thanks for the confirmation and additional info. I was looking for a match on the Fossil Guy website but I couldn't find one, clearly I was looking in the wrong part of the site. Seeing as Xiphiacetus is the most commonly found dolphin species in the Calvert formation, that seems like a good bet! Link to comment Share on other sites More sharing options...
Bjohn170 Posted January 17 Share Posted January 17 Nice jaw segment! Good find Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now