Shark Tooth Albian Of Tx

[erose]

Earlier this year I ran across this tooth in the Glen Rose Formation of Central Texas. It is from about the middle of the formation (Unit 3, Upper Member) and would be Lower Albian in age.

Note that it was found along with a few small round pychnodontid(?) teeth.

For scale the red arrow is about 4.5mm in length.

Not the small cusp between the large and outer cusp. There is a faint foramen on the lingual face. I will try and get sharper photos up if needed.

The closest I have come is Cretolamna appendiculata only in that it fits the age and has a few characteristics that match. But all the images I find in books or online are for much younger specimens.

Any ideas?

[Uncle Siphuncle]

compare w protolamna sokolovi and give us your thoughts

[erose]

compare w protolamna sokolovi and give us your thoughts

Looked at that one. The root is about right but this one has two cusplets and the lingual face does not have the distinct longitudinal ridges of P. sokolovi.

[Uncle Siphuncle]

hmmm... not that many shark species to choose from in tx as compared to contemporary ammos and echies, and the sharks seemed to range longer per species... i think your answer is right around the corner

[siteseer]

Erose and Dan,

I think that's an Archaeolamna tooth - tough to be sure. The lateral cusplets can look like they sit on their own mini pedestals of root from the lingual side. I can't tell if there are folds (=raised wrinkles) on the labial side near the base of the crown and cusplets. If there are no folds, that's an indication of an Archaeolamna. If it has folds, it could be a Cretodus. The size of the tooth is about right for either genus of that time.

That extra in-between cusplet is weird but we might expect some weirdness in early representatives of genera better known from the Cenomanian or later. Cretodus teeth are known for that but extra cusplets tend to be smaller in relation to the total size of the tooth - small enough for them to be called serrations (similar to some Mid-Late Eocene sand tiger shark teeth).

Jess

Earlier this year I ran across this tooth in the Glen Rose Formation of Central Texas. It is from about the middle of the formation (Unit 3, Upper Member) and would be Lower Albian in age.

Note that it was found along with a few small round pychnodontid(?) teeth.

For scale the red arrow is about 4.5mm in length.

Not the small cusp between the large and outer cusp. There is a faint foramen on the lingual face. I will try and get sharper photos up if needed.

The closest I have come is Cretolamna appendiculata only in that it fits the age and has a few characteristics that match. But all the images I find in books or online are for much younger specimens.

Any ideas?

[siteseer]

Erose,

I wanted to give this one a bump because it is so unusual and I don't think a lot of shark collectors saw this one. Also, I wondered if you were still thinking of adding some sharper photos.

In my research of another Albian tooth I learned that Archaeolamna teeth can have short folds on the labial face in juvenile lateral teeth. I have seen so few teeth from that far back in the Cretaceous, it would be interesting to get more opinions.

Jess

Earlier this year I ran across this tooth in the Glen Rose Formation of Central Texas. It is from about the middle of the formation (Unit 3, Upper Member) and would be Lower Albian in age.

Note that it was found along with a few small round pycnodontid(?) teeth.

For scale the red arrow is about 4.5mm in length.

Not the small cusp between the large and outer cusp. There is a faint foramen on the lingual face. I will try and get sharper photos up if needed.

The closest I have come is Cretolamna appendiculata only in that it fits the age and has a few characteristics that match. But all the images I find in books or online are for much younger specimens.

Any ideas?

[erose]

Siteseer,

I'm going to be out of pocket for a fortnight. I'll try and get some better photos up when I return.

Erich