Serrated Fin? - Devonian of Iowa

[BenWorrell]

I found this specimen in Black Hawk County, Iowa in a location with Devonian material. I think it's probably a fin, possibly from a gyracanthid. There are serrations that point away from the tip. Would love to hear if anyone has thoughts on what it is. Thanks!

[Darktooth]

Not a fin but a spine, not sure what species though.

[shark57]

Nice specimen. Definitely looks like a fin spine, hopefully someone can identify it.

[Fossildude19]

@jdp

[minnbuckeye]

Hey, I have seen that specimen somewhere! Very nice find.

[doushantuo]

It kinda does like a pectoral fin spine of a gyracanthid

[jdp]

Definitely not gyracanthid; the ridges would be arranged oblique to the long axis of the spine. I would actually lean towards identifying this as a chondrichthyan; there are a few Devonian "ctenacanthiforms" and this seems like it is probably one of them. Pretty rare and potentially important, depending on the age of the rocks you're looking in.

[doushantuo]

HAve to agree with you , " Ctenacanthid" fin spine is a better match, as regards ornament in particular

[BenWorrell]

On 11/5/2024 at 12:23 PM, jdp said:

Definitely not gyracanthid; the ridges would be arranged oblique to the long axis of the spine. I would actually lean towards identifying this as a chondrichthyan; there are a few Devonian "ctenacanthiforms" and this seems like it is probably one of them. Pretty rare and potentially important, depending on the age of the rocks you're looking in.

Thank you! This is from the Eagle Center Member of the Little Cedar Formation (late Middle Devonian). If there are any researchers interested in it I would love to connect. 

[jdp]

Thanks! I'll do a little reading and ask a few colleagues what they think and get back to you.