Unusual striated and serrated Isalo III tooth

[FF7_Yuffie]

Thoughts on this tooth I have. A 1cm serrated tooth from Isalo III. Striated and serrated.

 

Croc, or dinosaur? Could it be a type of Spinosaurid?

[Brevicollis]

Pictures are a bit to blurry to see fine details, but striations and serrations on one tooth would make me think that it might a type of still unnamed ceratosauridae tooth wich are known from this formation.

@Kikokuryu and @North might be able to help here 

 

https://en.wikipedia.org/wiki/Isalo_III_Formation

 

 

Edited July 6 by Brevicollis

[FF7_Yuffie]

1 minute ago, Brevicollis said:

Pictures are a bit to blurry to see fine details, but striations and serrations on one tooth would make me think that it might a type of ceratosauridae tooth. 

@Kikokuryu and @North might be able to help here 

Cheers, unfortunately can't find my phone stand and the like as I have just moved apartment. And I have shaky hands. If I find the stand, I will do some better photos. 

[Brevicollis]

4 minutes ago, FF7_Yuffie said:

Cheers, unfortunately can't find my phone stand and the like as I have just moved apartment. And I have shaky hands. If I find the stand, I will do some better photos. 

Its fine, the diagnostic features are still visible what should make a rough identification possible.

[North]

Im not able to help much, but far as Im aware there is not much described what comes to theropods in isalo III. Teeth are separated to morph types.

 

This tooth seems to have distal serations and ridges going around the tooth.

Theropods in general do not have ridges, except spinosaurids. Crocodiliforms do have those, and some has really similar teeth than theropods, so that would be an possible option.

 

But perhaps someone has more insight.

[Brevicollis]

@North, I've done some research and found out that the only crocodiliforms from that formation are Razanandrongobe and some unnamed Teleosaurids of wich only Razanandrongobe has serrations on his teeth, but no striations so far my research brought me.

 

Maybe teleosaurids have them both, but they're teeth from there are rather small, even when complete not much bigger as this one and even then not showing any signs of serrations.

 

I'll edit some pictures as examples later in.

 

So here they are : 

 

Razanandrongobe :

 

 

Teleosaurid :

 

And last but not least, Ceratosauridae indet.

 

That would be the best match, it has striations and serrations like the tooth we were talking about.

Picturecredit : @Jaimin013 for the ceratosauridae tooth, it was really hard to find a picture of one.

Edited July 7 by Brevicollis

[North]

5 minutes ago, Brevicollis said:

@North, I've done some research and found out that the only crocodiliforms from that formation are Razanandrongobe and some unnamed Teleosaurids of wich only Razanandrongobe has serrations on his teeth, but no striations so far my research brought me.

 

Maybe teleosaurids have them both, but they're teeth from there are rather small, even when complete not much bigger as this one and even then not showing any signs of serrations.

 

I'll edit some pictures as examples later in.

Usually teleosaurids have rounder teeth for capturing or crushing prey.

Often ones with more theropod like teeth are land crocs.

[Kikokuryu]

It does not belong to or match Razanandrongobe or teleosaurid croc.

 

This appears to be a Middle Jurassic ceratosaurid tooth similar to what you see in the premaxillary positions of Upper Jurassic Ceratosaurus sp.

 

Ceratosaurus is unique in having strong ridges that run down the tooth not too dissimilar to those of derived spinosaurids which appear in the Lower Cretaceous.

 

You see this morphology is all three Middle Jurassic deposits commonly available to collectors, the Isalo III Formation (Madagascar), Irhazer Shale (Niger), and El Mers Group (Morocco). I think it is only formally recognized/identified as ceratosaurid (previously basal spinosaurid) from Niger, while I think the Isalo paper is outdated either calling it dromaeosaurid or something else.

 

Ceratosaurid teeth from El Mers (left), Irhazer (Middle), Isalo (right) for comparison.

Edited July 6 by Kikokuryu

[FF7_Yuffie]

Thanks for the help. I will label it ceratosaurid, pretty cool. I assume they are quite rare, since there is little about them online.

[North]

6 hours ago, Kikokuryu said:

It does not belong to or match Razanandrongobe or teleosaurid croc.

 

This appears to be a Middle Jurassic ceratosaurid tooth similar to what you see in the premaxillary positions of Upper Jurassic Ceratosaurus sp.

 

Ceratosaurus is unique in having strong ridges that run down the tooth not too dissimilar to those of derived spinosaurids which appear in the Lower Cretaceous.

 

You see this morphology is all three Middle Jurassic deposits commonly available to collectors, the Isalo III Formation (Madagascar), Irhazer Shale (Niger), and El Mers Group (Morocco). I think it is only formally recognized/identified as ceratosaurid (previously basal spinosaurid) from Niger, while I think the Isalo paper is outdated either calling it dromaeosaurid or something else.

 

Ceratosaurid teeth from El Mers (left), Irhazer (Middle), Isalo (right) for comparison.

Never seen Ceratosaurus premaxillary teeth, but apparently Troodon did mention it on one point.

https://www.thefossilforum.com/topic/57022-identification-of-ceratosaurus-teeth/

 

Good to know that these teeth can have ridges.