Pathologic Shark Tooth

[Mike from North Queensland]

Last week while sieving through some macro material I noted this unusual shark tooth.

This is from the Cretaceous Albian Toolebuc Formation near Richmond Queensland Australia

The two photos of the tooth in question are 3 mm on the longest side the larger Bramble Shark tooth for comparison is 5mm long.

I suspect the tooth is question is a pathological Bramble but would like conformation

Thanks in advance Mike D

[MarcoSr]

Mike

The crown is really unusual for a Cretaceous bramble. The Cretaceous brambles that I personally have normally have only a single cusp with a distal heel like the other tooth that you posted. The root does however match a bramble root. See the below link for a modern E. cookei and E. brucus dentition.

http://homepage2.nifty.com/megalodon/Jawechinorhinidae.html

You can see the resemblance of the normal Cretaceous bramble teeth from the Australian, Albian Toolebuc Formation to the lower lateral teeth in the E. cookei dentition. If you were finding more of these unusual teeth they could be a different genus/species or just a positional variant in the bramble dentition. But most likely, your first tooth is pathological and is an example of how the teeth in the dentition would evolve as seen in the modern dentitions.

Marco Sr.

[Auspex]

Patho, or is there a symphysial position in this (or a related) species?

[MarcoSr]

Patho, or is there a symphysial position in this (or a related) species?

Chas

The modern E. cookei and E. brucus don't have symphyseal teeth. But it is possible that this Cretaceous species had symphyseal teeth. Bramble teeth from the Australian, Albian Toolebuc Formation are extremely common but I haven't seen a symphyseal pictured before but that is a possiblity especially based upon the crown of the tooth. I have over 100 specimens from 2mm to 6mm from a few lbs of matrix. However the damaged tooth is still 3mm which isn't that much smaller than the other 5mm specimen shown which is a large sized specimen based upon the ones that I have and ones that I have seen. I would expect a symphyseal to be smaller in relation to the regular teeth.

Marco Sr.

[siteseer]

Marco Sr.,

I agree that it is not a symphyseal tooth - too big. I have seen a similar tooth in a figure (Pfeil 1993, 191, 85, 2) showing part of a modern E. cookei lower dentition. It has an extra cusp like that but also has lateral cusplets (unlike Cretaceous-Early Eocene forms). The translated caption reads, "AL1 exhibits unusually enlarged extra cusp."

I don't think there is any documentation on Early Cretaceous Echinorhinus - almost none on Late Cretaceous ones.

Jess

Pfeil, F.H. 1983.

Zahnmorphologische Untersuchungen an rezenten und fossilen Haien der Ordnungen Chlamydoselachiformes und Echinorhiniformes. Palaeo Ichthyologica 1. Verlag Pfeil. Munich. May 1983.

Chas

The modern E. cookei and E. brucus don't have symphyseal teeth. But it is possible that this Cretaceous species had symphyseal teeth. Bramble teeth from the Australian, Albian Toolebuc Formation are extremely common but I haven't seen a symphyseal pictured before but that is a possiblity especially based upon the crown of the tooth. I have over 100 specimens from 2mm to 6mm from a few lbs of matrix. However the damaged tooth is still 3mm which isn't that much smaller than the other 5mm specimen shown which is a large sized specimen based upon the ones that I have and ones that I have seen. I would expect a symphyseal to be smaller in relation to the regular teeth.

Marco Sr.

[MarcoSr]

Marco Sr.,

It has an extra cusp like that but also has lateral cusplets (unlike Cretaceous-Early Eocene forms).

I don't think there is any documentation on Early Cretaceous Echinorhinus - almost none on Late Cretaceous ones.

Jess

Pfeil, F.H. 1983.

Zahnmorphologische Untersuchungen an rezenten und fossilen Haien der Ordnungen Chlamydoselachiformes und Echinorhiniformes. Palaeo Ichthyologica 1. Verlag Pfeil. Munich. May 1983.

Jess

There may not be much documentation on Cretaceous brambles because they are so rare a fossil find. Other than the E. australis from the Albian of Australia which are extremely common I don't recall seeing a picture of a bramble from the Cretaceous. Cappetta does list in his 2012 Handbook E. eyrensis from the Maastrichtian of a dragging site south of Australia and E. lapaoi from the Campanian/Maastrichtian of Quimbala, Angola and other reports from the Campanian of Morocco and British Columbia, Canada and the Maastrichtian of Chile.

I do have an Ypresian Eocene bramble from VA with a cusplet.

Marco Sr.

[siteseer]

Marco Sr.,

Yes, I have heard about a review of the sharks from the Northumberland Formation (Late Cretaceous, Campanian) of British Columbia being in the works for years and have seen a few brambles from there - even one that was as large as any more recent specimen.

That's a great specimen. I had seen only some Early Eocene specimens lacking cusplets from Morocco. I have one.

Jess

Jess

There may not be much documentation on Cretaceous brambles because they are so rare a fossil find. Other than the E. australis from the Albian of Australia which are extremely common I don't recall seeing a picture of a bramble from the Cretaceous. Cappetta does list in his 2012 Handbook E. eyrensis from the Maastrichtian of a dragging site south of Australia and E. lapaoi from the Campanian/Maastrichtian of Quimbala, Angola and other reports from the Campanian of Morocco and British Columbia, Canada and the Maastrichtian of Chile.

I do have an Ypresian Eocene bramble from VA with a cusplet.

Dad6-11-08Echinorhinus Priscus.JPG

Marco Sr.

[MarcoSr]

I came across this picture of an extant Echinorhinus brucus lower tooth in a recent publication of Géominpal Belgica. There is a lot of similarity to the tooth in question. So I definitely believe the tooth from the post is Echinorhinus.

Marco Sr.

[MikaelS]

Yes that's a pathological E. australis.

Echinorhinus is otherwise quite common in the Cenomanian of Western Australia:)