Oligocene pointy object: Waipatiid tusk?

[flyg]

Here's something I found in alluvium this fall. The location is Dorchester County, SC, Oligocene, almost certainly Ashley or Chandler Bridge formation. These formations are known for a variety of marine vertebrates including Elasmos and bony fish including Scombrids and billfish, marine turtles, cetaceans, sirenians, and crocodiles. Fresh water species are apparently rare.

 

This is about 4.5 cm long, less than 1 cm diameter. It is not quite round in cross section, but has a slightly flattened side. I want it to be a Waipatiid dolphin "tusk". These are known from the area. It doesn't seem to have any enamel. Could I be right, or am I completely off base? Opinions appreciated.

 

G

[Ramon]

Cool fossil!!! But I have no idea on what it is.

[ynot]

Does not look like a tooth. Maybe a fish spine.(?)

Nice whatever it is!

Tony

[flyg]

3 minutes ago, ynot said:

Does not look like a tooth. Maybe a fish spine.(?)

Nice whatever it is!

Tony

 

Bam. Searched on that, came up with shark dorsal spine. That looks good to me. Thanks!

 

G

[ynot]

That is a nice and rare find!!

 

Tony

[Harry Pristis]

If I had found this, I'd have called it a fish rostrum.

[jpc]

Look into soft-shelled turtle spines as well.   The ridges look like one to me.  I don't know if they exist in these SC formations since they are fresh water.  On the other hand, the surface I see in the last photo is not very soft shelly.   

 

http://www.skullsunlimited.com/record_variant.php?id=7766

[Al Dente]

It is a fish rostrum, probably one of the billfish or closely related. The two flat areas with the dimples are alveoli that held tiny teeth, similar to what modern swordfish and marlin have except modern ones aren't in the two rows like on this fossil.

 

I have looked around on the internet and this looks very similar to Aglyptorhynchus. There is a paper that lists three species of Aglyptorhynchus from the Oligocene of South Carolina but I can't access the paper. Nice find by the way. I would be very happy finding this.

[flyg]

Awesome. Billfish rostrum is right on. It still really looks superficially like a shark spine to me, but it's much too young to be a Hybodont and Squaliforms and Heterodontus sp. are not known here from what I can see. Billfish on the other hand are well known. Here's a hypural from the same location that looks (to me) a lot like Aglyptorynchus also. Good call, thanks.

 

G

[Al Dente]

I just added a picture of Aglyptorhynchus that I found on the internet to my original reply.

[Boesse]

I agree with Al Dente on this one - good eye. I almost thought fish spine as well, but it seems to be a tiny Aglyptorhynchus (perhaps a juvenile).