Cretaceous Fish Scale Id

[mdpaulhus]

Can any one help with identification of a fish scale. This one is from the Mowry shale (middle cretaceous, cenomanian) just south of Billings Montana. This is the largest one I found at 1.75" wide and 1.5" tall (large for any of today's fish).

[Auspex]

That's a big ol' guitar pick; great find!

(I'll watch for the ID...)

[Carl O'Cles]

Thats pretty cool, not sure what species it is but i bet you could sell it on E-bay as a early hominid finger print and get a pretty penny for it

[raptorclaws]

The Mowry Shale has many exposures throughout Montana, Wyoming, Utah, etc....similar aged formations continue up into here in Alberta. The scale is a bony fish, some type of teleost....your scale looks a lot like a suborder that was common in the Cenomian, the 'Protacanthopterygii'. When we find Cretaceous fish scales they are usually either the ganoid scales of Garpike (Lepistsoteus) or the concentric scales (like yours) of Protacanthopterygii. Lepistosteus up here are usually found loose (throughout the Campanian and Maastrichtian) and those of Protacanthopterygii are 'usually' in split shale matrix from earlier Cretaceous Deposits.

I doubt if there is any way of identifying the scale to a family level. Or, if it is, it would have an element of educated guessing.

Value of this post: 2 cents. Years of experience that make an answer sound good even though it may be all baloney.

[ShadowElite951]

The scale looks like a cycloid scale...so narrow down the search to cretaceous fish in montanaish area with cycloid scales...

Maybe Apsopelix, Enchodus, Cimolichthys?

[mommabetts]

Cool find, even if you never know for sure which fish it belongs to.

[Diceros]

Even though the part with the ctenii is broken off at the bottom, from the non-overlapped area at the top, I'd say it's ctenoid rather than the simpler (and less common) cycloid bony fish scale. The hard, inflexible, enamel-covered, diamond-shaped ganiod scales of fish like gars look entirely different. The Mowry's famous for its fish scales, but most never get specifically identified.

[IH8Bentonite]

I recently found a fossil fish scale very similar to the one you found. It was found in the Mowry Shale in the Bighorn Basin near Sheep Mountain in Wyoming. Mine is approximately 1.5" wide by about 2.5" tall. I was participating in a geology field camp class and thus had access to a friend of my professors who is considered a fossil expert. He cannot positively identify the fossil but told me that the fish scale is most probably from a fish in the family Ichthyodectidae, which are known to have lived from the Jurassic to the Late Cretaceous and had members of the family that grew up to 5 meters in length. However, my scale was more ovate shaped and less round. If I had to guess, I would guess Xiphactinus.

Edited June 22, 2017 by IH8Bentonite
Additional Info