Interesting Tooth From STH

[JBMugu]

Hi Everybody,

 

I found this tooth the other day and it looks different from all the other teeth I have found in the STH area. The tooth resembles (to me) a Isurus lower but it has clear cusps on both sides of the tooth. I looked on elasmo and I don't see anything that looks quite like it listed for Bakersfield. The only thing I saw that looked like it had cusps was a catshark  but the root doesn't seem to match. Maybe a Isurus Retroflexus? I'm stumped please weigh in with ideas. (I will try for better pictures tonight) Thank!

 

Jesse

[Fossil-Hound]

It's not an Isurus retroflexus as there are side cusps. These are I. retroflexus:

 

 

I'm from Maryland and these teeth are similar to sand tiger but I'm not sure if that's the species but you will find sand tiger with side cusps.

[JBMugu]

Maybe a juvenile C. hastalis? I know @ynot had a similar tooth posted under "Odd shark tooth from STH"

[Doctor Mud]

The example from Fossil-Hound is an anterior tooth, these don't have cusps.

 

Here is a lateral tooth from the Elasmo.com site listed as Isurus retroflexus and from STH.

 

 

On the Elasmo site you can look at tooth variation in the jaw in Isurus (and other sharks) here:

 

http://www.elasmo.com/genera/reconstruct/the_recon.html?sp=has-n

[sagacious]

On ‎6‎/‎14‎/‎2017 at 10:55 AM, JBMugu said:

Maybe a juvenile C. hastalis?

 

Hi Jesse,

 

Based on the photos, yes, your tooth appears to be an anterior lower from a juvenile Carcharodon hastalis.  Occasionally one finds West Coast C hastalis with side cusps.  These side cusps are perhaps most often seen on lower teeth, and especially on juvenile teeth -- although on rare occasion adult teeth can be found with distinct cusps. 

 

Don't let the small side cusps derail your identification process.  Although various extinct and extant Isurus and Carcharodon spp teeth may occasionally have small side cusps, which has the potential to confuse the species identification, the crown and root of your tooth appear otherwise indistinguishable from C hastalis. 

 

Below is a 1.5"+ upper lateral cusped C hastalis tooth collected from West Coast Late Miocene strata, showing that cusps may persist beyond the juvenile stage on some individuals.