Paleozoic Shark Teeth

[geofossil]

Here's some paleozoic shark material from the Rockies west of Calgary. Most of the exposures are Late Devonian and Carboniferous. The shark material usually appears as 'blue-black' calcium phosphatic specimens on the outside of rocks. There is no real pattern in the formations where shark material may be but searching around usually finds some. The challenge is more in the hiking and exposure than finding fossils. It would take several life times just to scratch the surface of all the places to look. One can't collect material in the national parks but there is enough other areas to keep the keener occupied. Not too far (as the crow flies) to the west of these photos, across the Divide, are Cambrain exposures including the Burgess Shale in Yoho Natioal Park.

Some of the specimens have been freed from matrix using acetic acid and others are left in matrix. Usually a hunk of dissolved limestone will produce shark teeth too small to photograph and often other fauna such as conodonts. The specimens have been identified to the genus level but, as with most paleozoic vertebrates, there has been little study and location is the most important variable.

The photography is not the best as I used an HP scanner and some specimens are just a third of a centimeter or so. The scenery photos are to give some perspective of the terrain...not exactly a flat field. The first photo isn't mine but taken by a friend.

From the bottom

Getting 'up there'

Petalodus

Petalodus

Cladodus

Cladodus

Hybodus

Hybodus

Chomatodus

Deltodus

Hybodus

Helodus

Orodus

Acrodus

Cladodus

Deltodus

Orodus

Sandalodus

Psammodus

Orodus

Polyrhizodus

Helodus

[Mike Owens]

Very nice! What is the size range for these teeth? The sharks were not as large then as the later ones.

Mike

[Gatorman]

Very cool teeth :Thumbs-up:

[geofossil]

Very nice! What is the size range for these teeth? The sharks were not as large then as the later ones.

Mike

Most of the specimens I have are from a few millimeters up to 3 centimeters wide (usually the flat Deltodus and similar teeth are the largest) It's hard to judge the sizes of sharks back then as there is a bias towards preservation of smaller material. I've seen a few whopper crushers about 6cm in width embedded in rocks. I have one plate of scales from a Carboniferous specimen and it would indicate a large creature but I'm not sure if it's a shark group or not. I'll have to post a photo and get help with it. The other issue is that the Late Paleozoic spans several tens of millions of years so the fossil record of larger sharks may not exist or may not yet have been discovered.

A few years back I was doing some field work north of Las Vegas. (there's good fossil collecting about 20km west of Glendale). I'm mostly interested in brachiopods but I came across a large tooth swirl from a Helicoprion. Unfortunately it was in a multi ton boulder. the tooth swirl was 4 inches in diameter. I've always found that an interesting genus. There are specimens from the Permian formations of Arctic Canada, A few spots in Russia and in Australia but I hadn't ever read anything about southern USA findings.

[Gatorman]

Unfortunately it was in a multi ton boulder.

Its hammer time :shades:

[Gatorman]

Ok, my apologies that was corny

[Northern Sharks]

I would have loved to see pics of that Helicoprion whorl. Great teeth considering I'd never heard of any from Alberta yet. I have relatives in Red Deer and Calgary; maybe a visit is in order hmmmm......

[geofossil]

Its hammer time :shades:

Afer 30 years I could write a book on rock hammer use...what mostly NOT to do. Lucky to still have both eyes and, at last count, my fingers. Victim several times of 'the infamous bounce'... still have my own front teeth but only thanks to my dentist.

[Gatorman]

ouch