Spineless fossil fish

[Jose Montemayor]

Hi there, 

 

Could you please help me identify this fossil fish? It’s from the Vallecillo formation in northeast Mexico. Late Cretaceous. The fish is approximately 93 cms long and the head is 32 cms long which I found as a strange proportion. It lacks of vertebrae. I’m clueless with this one.

[Jose Montemayor]

[Fossildude19]

This looks like a Pachyrhizodus sp.

 

EDIT:  The reason you don't see the spine is because this fish is literally belly up, as it were. (Ventrally preserved.)

The vertebrae may be buried beneath the matrix. 

[oilshale]

Holostei (for example this Caturus or this Proscinetis) don't have much of a spine - only a thin layer of bone covers a mostly cartilaginous skeleton. But there should be fins - the dorsal, anal and pelvic fins are missing. The head seems to be ok, but the body looks very strange. I wouldn’t be surprised if it is (partly) faked.

[Fossildude19]

@Ptychodus04  Kris is familiar with these fish. 

Maybe he will have some ideas. 

 

I don't see any signs of fakery here. It would be a strange way to fake a fish, I think.

At least, nothing jumps out as outright fake. There are 4 visible breaks in the plate, which I would expect from a plate that is 3 + feet long.

 

 

This is the proper orientation of the fish: 

 

 

 

It may be an artifact of the way it was prepared. It does look awfully smooth. 

Perhaps it was prepared by grinding down the rock? 

[Ptychodus04]

Blanco-pinyon et al 2003 lists Ichthyodectiformes indet. from Vallecillo, Mexico. The copy I have is a really bad scan so the figures are poor quality but the overall look is the same. This fish definitely has ichthyodectiform caudal fin, pectoral fins, and skull shape IMHO.
 

I can’t find a reference to a Vallecillo Formation. Are these possibly from a locality physically near Vallecillo, Nuevo León? If so, they are probably from the Agua Nueva Formation (Late Cretaceous, Turonian).

[oilshale]

Vallecillichthys multivertebratum (Teleostei: Ichthyodectiformes), a Late Cretaceous (early Turonian) “Bulldog fish” from northeastern Mexico.

Vallecillichthys multivertebratum.pdf

[Pemphix]

6 hours ago, oilshale said:

Holostei (for example this Caturus or this Proscinetis) don't have much of a spine - only a thin layer of bone covers a mostly cartilaginous skeleton. But there should be fins - the dorsal, anal and pelvic fins are missing. The head seems to be ok, but the body looks very strange. I wouldn’t be surprised if it is (partly) faked.

 

 

1 hour ago, Fossildude19 said:

I don't see any signs of fakery here. It would be a strange way to fake a fish, I think.

At least, nothing jumps out as outright fake. There are 4 visible breaks in the plate, which I would expect from a plate that is 3 + feet long.

It may be an artifact of the way it was prepared. It does look awfully smooth. 

Perhaps it was prepared by grinding down the rock? 

 

31 minutes ago, Ptychodus04 said:

Blanco-pinyon et al 2003 lists Ichthyodectiformes indet. from Vallecillo, Mexico. The copy I have is a really bad scan so the figures are poor quality but the overall look is the same. This fish definitely has ichthyodectiform caudal fin, pectoral fins, and skull shape IMHO.
 

I can’t find a reference to a Vallecillo Formation. Are these possibly from a locality physically near Vallecillo, Nuevo León? If so, they are probably from the Agua Nueva Formation (Late Cretaceous, Turonian).

 

As oilshale said: spine is usual, no point to worry about. IMHO one fin is partially present, but close to the body. There are two possibilitys concerning the rest of the missing fins: 

- the fins are simply grinded away, given the deepness of the preparation on the plate.

- maybe with some luck some of the fins survived the prep and are still in the matrix (the fins of Vallecillichthys are not so close to the body, see picture in publication) 

 

As Fossildude says: no obvious signs of forgery imho here.

 

Ptychodus nailed it: imho it's Vallecillichthys multivertebratum BLANCO & CAVIN 2003, an Ichthyodectiformes from late cretaceous of Mexico (Turon), Vallecillo, Agua Nueva Formation. 

Publications see here:

https://www.pfeil-verlag.de/wp-content/uploads/2015/05/4_59d01.pdf

https://www.researchgate.net/publication/286704679_Late_Cretaceous_Turonian_fish_assemblage_from_Vallecillo_Northeastern_Mexico

https://www.researchgate.net/publication/248554029_New_Teleostei_from_the_Agua_Nueva_Formation_Turonian_Vallecillo_NE_Mexico

[RJB]

Very cool fossil, but yeah, the intire slab looks like it has been 'worked'. 

 

RB

[Fossildude19]

Thanks to Kris and Pemphix and Thomas for weighing in on this. 

Thanks also, for all of the links. 

Learned something new today!    

[Jose Montemayor]

12 hours ago, Fossildude19 said:

This looks like a Pachyrhizodus sp.

 

EDIT:  The reason you don't see the spine is because this fish is literally belly up, as it were. (Ventrally preserved.)

The vertebrae may be buried beneath the matrix. 

Thanks a lot. I do think it might be a Pachyrhizodus sp. I’ve seen a couple more of this species and at this location it’s very common to see them belly down. I don’t know why I didn’t consider the belly up option right away. Thanks again for your response.

 

Jose.

 

 

[Jose Montemayor]

2 hours ago, Ptychodus04 said:

Blanco-pinyon et al 2003 lists Ichthyodectiformes indet. from Vallecillo, Mexico. The copy I have is a really bad scan so the figures are poor quality but the overall look is the same. This fish definitely has ichthyodectiform caudal fin, pectoral fins, and skull shape IMHO.
 

I can’t find a reference to a Vallecillo Formation. Are these possibly from a locality physically near Vallecillo, Nuevo León? If so, they are probably from the Agua Nueva Formation (Late Cretaceous, Turonian).

You are totally right. The town where the quarry is located is Vallecillo, and the formation is in fact Agua Nueva. 

[Jose Montemayor]

8 hours ago, oilshale said:

Holostei (for example this Caturus or this Proscinetis) don't have much of a spine - only a thin layer of bone covers a mostly cartilaginous skeleton. But there should be fins - the dorsal, anal and pelvic fins are missing. The head seems to be ok, but the body looks very strange. I wouldn’t be surprised if it is (partly) faked.

Thanks a lot for your response. I think that the fins can be still inside the matrix. It’s not fake but really bad ‘prepared’. Not many skillful people that I know in this area.

[Tidgy's Dad]

This thread is most interesting and a nice example of knowledgeable forum members working together to come to a conclusion. 

[Ptychodus04]

41 minutes ago, Jose Montemayor said:

I do think it might be a Pachyrhizodus sp.

I think the fins are wrong for Pachyrhizodus. They look more like Ichthyodectid fins

 

2 hours ago, Pemphix said:

Ptychodus nailed it

Technically @oilshale nailed it. I simply pointed in the right direction for the game of pin the ID on the fish.

[Ptychodus04]

36 minutes ago, Tidgy's Dad said:

This thread is most interesting and a nice example of knowledgeable forum members working together to come to a conclusion. 

Exactly what the forum is for in my opinion.

[Jose Montemayor]

11 hours ago, Fossildude19 said:

@Ptychodus04  Kris is familiar with these fish. 

Maybe he will have some ideas. 

 

I don't see any signs of fakery here. It would be a strange way to fake a fish, I think.

At least, nothing jumps out as outright fake. There are 4 visible breaks in the plate, which I would expect from a plate that is 3 + feet long.

This is the proper orientation of the fish: 

It may be an artifact of the way it was prepared. It does look awfully smooth. 

Perhaps it was prepared by grinding down the rock? 

Sadly it was a really bad preparation. As you mention, the rock was grinded which ultimately made the fossil look ‘manipulated’ but it’s not fake I saw it on the quarry. The rock when it was extracted measured approximately 1.45 meters and was tremendously heavy. 

[Jose Montemayor]

3 hours ago, oilshale said:

Vallecillichthys multivertebratum (Teleostei: Ichthyodectiformes), a Late Cretaceous (early Turonian) “Bulldog fish” from northeastern Mexico.

Vallecillichthys multivertebratum.pdf

I don’t think this is a Vallecillichthys multivertebratum. That one is much more common and has completely different proportions. Head, tail and body size are completely different.

 

 

[Jose Montemayor]

Just now, Jose Montemayor said:

I don’t think this is a Vallecillichthys multivertebratum. That one is much more common and has completely different proportions. Head, tail and body size are completely different.

 

 

 

[rfarrar]

Looks like something in the Pachycormidae.

[Jose Montemayor]

9 hours ago, Ptychodus04 said:

I think the fins are wrong for Pachyrhizodus. They look more like Ichthyodectid fins

 

Technically @oilshale nailed it. I simply pointed in the right direction for the game of pin the ID on the fish.

Could it be possible that instead of a Vallecillicthys multivertebratum this one might be another Ichthyodectiformes like Gillicus arcuatus? @oilshale @Ptychodus04 @Pemphix @Fossildude19

 

By the way, thanks everyone for your valuable comments. I didn’t expect that much information!

[Ptychodus04]

@Jose Montemayor there’s always the possibility that it is not the most likely option but without more research and seeing the piece in person, most of us would agree that it is more prudent to err on the side of conservatism.

[Jose Montemayor]

11 minutes ago, Ptychodus04 said:

@Jose Montemayor there’s always the possibility that it is not the most likely option but without more research and seeing the piece in person, most of us would agree that it is more prudent to err on the side of conservatism.

@Ptychodus04 Certainly it would be better if you could watch the piece in person. Maybe that’s why I’m not fully convinced about this one being Vallecillicthys. I’ll post a picture of the best preserved Vallecillicthys multivertebratum I have to see if you change your mind. Thanks a lot!

 

[Ptychodus04]

12 minutes ago, Jose Montemayor said:

I’ll post a picture of the best preserved Vallecillicthys multivertebratum I have to see if you change your mind

Yep, that’s not the fish in question. Consider my mind changed.

 

Pachycormidae (as suggested by @rfarrar) is a definite possibility as well as some other Ichthyodectidae. 

[oilshale]

I took another look at the head of your fish - you're right, it's not Ichthyodectiformes. Maxilare and Dentale look different with Ichthyodectiformes - they are much more massive. Pachycormidae is getting closer. But I lack the expertise. I am not an ichthyologist or paleontologist - just a polymer chemist.

Thomas