Cretaceous Eagle Ford fish material?

[claire01]

Front, back, end views. Approx. 3" x 1.5" If fish, what part?  I've never seen this before. 

[Fossildude19]

If it is fish material, ... I would guess it to be part of a caudal fin (tail) of one of the large fish from the Cretaceous that are common to the area.

[claire01]

Thanks, Tim.  Here are a couple of other views. Could it be something other than fish material?  That's often what I run across here.

[Mike from North Queensland]

I agree looks like fish material But I believe it to be front dorsal fin material as these are fairly ridged bones or spines,

where as caudal fin material usually is made up of hundreds of small bones to enable flexibility.

 

Mike D

 

[ynot]

I hate to be a dissenter, but it looks more like burrows infilled with iron concretions to Me. The cross section shape varies, and they are not on a single plane as would be expected from a fish fin.

I may be way off, but this is My opinion of this piece.

 

Tony

[abyssunder]

Considering the location, looks to be there two possibilities : fish fin and Teredolites (teredinid borings in petrified wood).
For the fish fin the resemblance could be good with the specimen from this thread :

 

What I see interesting is that the "elements" of the two comparable specimens in transverse section are somehow quadrangular or angular, which I think is not a characteristic aspect for teredinids (they borings are more circular in shape).

[Mike from North Queensland]

I will stick to my original front dorsal fin as the id as the background material with the fossil looks to be sediment infill rather than wood.

Also the Teredolites I have seen tend to taper at the end of there root and for the diameter shown in the request for id they would be exceptionally long.

Attached for reference are two random caudal fin bones with a total length of 7 mm and a dorsal fin from my collection - these are all cretaceous fish specimens.

 

Mike D'Arcy

[claire01]

Thanks everyone.  I ran across this thread here on TFF today and I'm feeling pretty confident that it is indeed fish material and likely from either a caudal or dorsal fin.  I'm leaning toward caudal.  Now, what fish might this be from? . 

 

[Mike from North Queensland]

Clair01

 

Look at the pair of caudal fin bones in my post above yours is not a caudal fin as they are made from lots of small bones to give flexibility.

I do not know what fish but definitely dorsal fin bones.

Did a bit more research and could also be pectoral fin

 

Mike D

 

Edited September 26, 2016 by Mike from North Queensland
added pectoral fin as an option

[Fossildude19]

I was basing my guess on images I have seen of caudal fins of fish from the American mid-west. 

 

Cimolicthys:

 

 

I think @Xiphactinus  or @KansasFossilHunter or @Ptychodus04  could be helpful with determining what type of fin and fish yours are from, Claire. 

Regards,

[claire01]

And I thank you! It's incredibly helpful to have a starting point for more research, fossildude!  You guys are the best. 

[Fossildude19]

Please, call me Tim. 

Fossildude19 is so long to type.  

 

[claire01]

Will do. And thanks again.

[Fossildude19]

You are more than welcome. 

[Ptychodus04]

I would call this a fragment of Ichthyodectid caudal/dorsal fin. It is VERY similar to that of Xiphactinus audax who had rather rigid fins all around.

[claire01]

Oh thank you, that's exciting!  I did find a xiphactinus vertebrae in this same spot some time ago. 

[doushantuo]

cavendcretacpiscexiphactinOP650gillicichthyodec.pdf

[Xiphactinus]

Hi! Late to the party. Haven't been online for a few days. Most definitely cross sections of a fish tail. Not enough there to ID beyond that really.

[claire01]

Thank you!