Carcharodon hastalis - Chile

[BellamyBlake]

I have here an alleged Carcharodon hastalis from Chile. It is 1.85" long and 1.12" wide.

 

After receiving the tooth, it looked a lot more like Isurus planus to me. The other party insists it's Carcharodon hastalis. At the very least, they insist it comes from Chile. To the best of my knowledge, Isurus planus isn't found in Chile. I've never heard of it anyway. 

 

Two questions, then. Is this Hastalis or Planus? And if it is Planus, might it be Chilean? 

 

Thank you,

Bellamy

[BellamyBlake]

[LabRatKing]

Lots and lots of fossil shark teeth out of Chile these days, including Isurus AKA Cosmopolitodus. 

 

It seems a bit narrow for C. hastalis to me.

This in fact looks like a planus to me...somewhere around here I have a bunch in a box from my Bakersfield days and they look exactly like this one.

 

There are scattered reports of I. planus from Chile. Mostly academic regurgitation of Heim 1998, which is a bit lacking in the details department...and oddly enough the paper is based on specimens from Sharktooth hill. 

 

After a bit of digging the claims of Chilean planus get even sketchier as they all cite  Eldridge and Arnorld 1907....and it too is about Sharktooth hill, not Chile. 

 

Ironically enough, I managed to find a report with images on penguin fossils found conspecifically with hastalis in Chile and the images look like Isurus rather that hastalis to me too.

 

So, your guess is as good as mine, given the unstable nature of the taxonomy.

 

The Penguin paper: https://www.redalyc.org/pdf/1739/173928393005.pdf

 

 

 

[Al Dente]

Here’s a hastalis tooth set from the www.elasmo.com website.

 

 

[siteseer]

I also think it is a Carcharodon planus tooth.  It's not a slam-dunk, though, especially if that profile view is not a direct shot at the edge of the the tooth.  C. planus has a flatter crown than hastalis.  There are hastalis teeth that resemble planus but they tend to be slightly thicker than you'd see in planus especially at the base of the crown.  However, it does have the root of a planus. 

 

I use Carcharodon for planus because it appears to have descended from C. hastalis sometime in the early to early-middle Miocene. 

 

It does look more like a tooth from the late Miocene to early Pliocene of Chile - sites in the Caldera area - than a Bakersfield tooth or one from southern California sites.  Sharktooth Hill Bonebed teeth do grade in color into brown but a brown tooth is a rare find.  It sticks out among other teeth from the layer.  The teeth from Chile tend to be brown and the preservation is more like a tooth that has sat on the surface getting weathered.  It is my understanding that a lot of teeth there are found weathering out on the surface.  Sharktooth Hill Bonebed teeth can be weathered but they are generally more bleached out from being washed by groundwater somewhat close to the surface.  Collectors have generally had to dig down through 10 feet of overburden to get to the layer.  There are spots where the layer is near at the surface (various private quarries) but the teeth get picked up before they sit too long.

 

The odd thing about C. planus and C. hastalis is that neither is known from the early-middle Miocene of California until their occurrence in the middle Miocene STH Bonebed.  Both are absent in the lower part of the Round Mountain Silt.  However, C. hastalis is known from the early Miocene of the east coast of the U.S. and planus has been reported from the early Miocene of Australia.  Both have been reported from the late Miocene (and perhaps the early Pliocene) of California.  It's possible that planus ranged as far south as Chile by the late Miocene.

 

I would ask the source about why he's so sure it's from Chile.  Weird stuff has come out of Chile.  It's possible it comes from there and it looks the part but nailing down the locality is important basic information.  That tooth is in the upper part of the size range for planus but more in the middle of the size range for hastalis.  A random find of a tooth not otherwise known from a site would be more likely around the average size.  It makes me a little suspicious that it could be a California tooth.

 

These are all the things that went through my head after I read through this thread.

 

Jess

[aeon.rocks]

Bakersfield. Which is good, you don't need papers for it.