The One that Didn't Get Away

[cthomp50]

This is my best find to date and I would love your input and observations...  I found this specimen in McKinney Texas (suburb north of Dallas) in late 2020.  While my wife my was antique shopping, I went to a local housing development to look for fossils.  To my surprise I found this beautiful tail fin in the Austin Chalk formation.  It was in about a 300 lb boulder, but it was well worth the effort to salvage it.  I have returned to the area to search for more sections, but after hours of searching I haven't found anything new.  In the original boulder, I also found a suspected scale and a single vertebrae. I also have only a small part of the matching side.  I have now cut down to pieces and would like to present them to you for your insights.  I tried to picture them in different lights/contrasts for you.  (the measuring stick is in inches, the only measure I had in the house)

[cthomp50]

[cthomp50]

Tail with measurement

[cthomp50]

Tail without measure

[cthomp50]

various light

[cthomp50]

Various light 2

[cthomp50]

various light 3

[Fossildude19]

It's in rough shape, ... not sure it can be identified to genus or species. 

I would put a guess in as Ichthyodectidae. 

 

Maybe Kris @Ptychodus04 may have some insights to share. 

[cthomp50]

various light 4

 

[cthomp50]

various 5

[cthomp50]

6

[cthomp50]

Scale?

[cthomp50]

scale 2?

[cthomp50]

vert

[cthomp50]

vert 2

[cthomp50]

small matching side

[abyssunder]

2 hours ago, cthomp50 said:

scale 2?

My first impression set me to think is a possible fish scale.

[Thomas.Dodson]

Definitely a fish scale. Nice stuff.

[connorp]

Great finds!

[Ptychodus04]

It is really impossible to ID fish material without cranial preservation any better than family with a guess at a genus. That being said, this looks like Pachyrhizodontidae to me and it only contains 1 genus, Pachyrhizodus sp. 

 

Based on the size, you could argue an ID of Pachyrhizodus sp. cf. minimus.

[IsaacTheFossilMan]

On 02/02/2021 at 9:38 PM, cthomp50 said:

This is my best find to date and I would love your input and observations...  I found this specimen in McKinney Texas (suburb north of Dallas) in late 2020.  While my wife my was antique shopping, I went to a local housing development to look for fossils.  To my surprise I found this beautiful tail fin in the Austin Chalk formation.  It was in about a 300 lb boulder, but it was well worth the effort to salvage it.  I have returned to the area to search for more sections, but after hours of searching I haven't found anything new.  In the original boulder, I also found a suspected scale and a single vertebrae. I also have only a small part of the matching side.  I have now cut down to pieces and would like to present them to you for your insights.  I tried to picture them in different lights/contrasts for you.  (the measuring stick is in inches, the only measure I had in the house)

Correct me if I'm wrong, but that looks a bit like a wheelie bin? Trashcanoidea, if I'm not mistaken!

[IsaacTheFossilMan]

23 hours ago, cthomp50 said:

various 5

On a more mature note, absolute gorgeous find! You're a very lucky man! Correct me if I'm wrong, but is Dallas' strata Cretaceous? (so I can see if I may be of help, and to confirm my suspicions!)

 

Right, I'm off for a nap, see everyone tomorrow! Or later, based on the fact you live across the pond! Will give you my opinion soon, after I've slept on it, but, I can quickly say, it's looking to me like it could be a Lepisosteiformes, especially since they're quite common in Dallas! 

[Ptychodus04]

16 hours ago, IsaacTheFossilMan said:

Correct me if I'm wrong, but is Dallas' strata Cretaceous? (so I can see if I may be of help, and to confirm my suspicions!)

 

Right, I'm off for a nap, see everyone tomorrow! Or later, based on the fact you live across the pond! Will give you my opinion soon, after I've slept on it, but, I can quickly say, it's looking to me like it could be a Lepisosteiformes, especially since they're quite common in Dallas! 

The rock in this area is the Late Cretaceous Austin Chalk. 
 

Extant Leoisosteiformes are extremely common in this area. Fossilized specimens, not so much. Either way, the structure of the tail is all wrong. This specimen has a deeply forked tail where gars have a more fan-shaped tail.

[IsaacTheFossilMan]

1 minute ago, Ptychodus04 said:

The rock in this area is the Late Cretaceous Austin Chalk. 
 

Extant Leoisosteiformes are extremely common in this area. Fossilized specimens, not so much. Either way, the structure of the tail is all wrong. This specimen has a deeply forked tail where gars have a more fan-shaped tail.

I agree with the tail point, after further research earlier, I'm still compounding my ideas to try to identify it. However, I have seen lots of fossil Leoisosteiformes hailing from this area. But, I agree, back to the drawing board for me!

[IsaacTheFossilMan]

On 03/02/2021 at 2:44 AM, Ptychodus04 said:

It is really impossible to ID fish material without cranial preservation any better than family with a guess at a genus. That being said, this looks like Pachyrhizodontidae to me and it only contains 1 genus, Pachyrhizodus sp. 

 

Based on the size, you could argue an ID of Pachyrhizodus sp. cf. minimus.

If I recall correctly, Pachyrhizodus first appeared in the Cretaceous. I researched on the possibility of this being the ID, and, after seeing promising results, I realised that.
EDIT: I'm an idiot, for some reason I thought Dallas was Triassic for a moment.
Also, the scale is cycloid, for what that's worth!