Vertebra Queensland

[Mike from North Queensland]

Looking through my usual matrix I came across this partial vertebra that has me stumped.

Both sections were sitting together in the matrix so assume they are part of the same vertebra.

Definitely not fish so some type of reptile ?

Hopping the process end is diagnostic enough to determine species.

Second piece in post below

 

Mike 

[Mike from North Queensland]

Second piece

[Mike from North Queensland]

The length of the longest dimension of the second piece is 35 mm.

The widest length of the first piece is 24 mm

 

Thanks in advance for any or all input

 

Mike D'Arcy

[ynot]

Neat looking piece(S).

Maybe @old bones will have an idea.

[Miocene_Mason]

Do you have an approximate age?

[Mike from North Queensland]

Good start to the day the material came from the toolebuc formation - marine cretaceous deposits from Richmond Queensland Australia.

These are albian in age so 98 to 100 million approximately

[The Amateur Paleontologist]

Well-preserved bones, they're rather cool  I'm thinking some of the bones might be plesiosaur cranial elements

[GeschWhat]

[old bones]

I'm afraid that I don't have anything useful to add... I hope that you can get an ID, it's an intriguing piece.

[JohnBrewer]

On 19/06/2018 at 11:15 AM, The Amateur Paleontologist said:

Well-preserved bones, they're rather cool  I'm thinking some of the bones might be plesiosaur cranial elements

I agree 

[DE&i]

Intriguing finds @Mike from North Queensland they appear to be neural spine and neural arch elements. And would be perhaps match up with your vertebra that was in the matrix. 

Edited August 25, 2018 by DE&i
Additional information

[Mike from North Queensland]

I got an id for these pieces as a reptile basioccipital and exoccipital so now to find out from what

 

Mike

[Mahnmut]

Maybe @pachy-pleuro-whatnot-odon can help further?

Best Regards,

J

[pachy-pleuro-whatnot-odon]

Well, isn't this the mystery, going on for over 4 years!

 

On 8/24/2018 at 9:30 PM, DE&i said:

Intriguing finds @Mike from North Queensland they appear to be neural spine and neural arch elements. And would be perhaps match up with your vertebra that was in the matrix. 

 

I must admit that this was my first impression as well, when I looked at the pieces. However, this wouldn't quite fit, as in the first piece that'd mean there'd be a solid bone strut connecting the vertebra to the neural arch, which is a configuration I've never seen before, in reptile nor mammal. And for the second piece, it'd imply an outgrowth on the spinous process (which would, moreover make the process too thick), which makes this interpretation unlikely as well...

 

14 hours ago, Mike from North Queensland said:

I got an id for these pieces as a reptile basioccipital and exoccipital so now to find out from what

 

Although I probably wouldn't have been able to come up with this interpretation myself, it does make perfect sense now that it's mentioned - especially the basioccipital, which is something I've seen ichthyosaur specimens off. The pattern of radiating grooves seen at the bottom of the photograph below is very typical of them:

 

On 6/19/2018 at 1:44 AM, Mike from North Queensland said:

 

In my opinion, however, the basioccipital is not round and bulbous enough to be that of an ichthyosaur or plesiosaur, which basioccipitals are relatively large and marked (but maybe @RuMert or @fossils-uk have a different opinion). Instead, I believe there's a small dip at the top of the rather small basioccipital condyle that reminds me of the basioccipitals seen in crocodiles. Compare with the below Fig. 8 of Ruger Porter, Sedlmayr and Witmer (2016). And while that figure is of Alligator mississippiensis, I do believe it's still a valid comparison for other crocodilians. In any case, with ichthyosaurs and plesiosaur being ruled out, and it being too early for mosasaurs, crocodilians seem a good option. Maybe @caterpillar has an opinion about this?

 

 

Unfortunately, I don't have a lot of reference material from the backs of skulls of marine reptiles, as those skulls are often either flattened or, when not, mounted as part of a skeletal reconstruction or so as to show the more impressive front of the specimen. This makes the second specimen more difficult to place. But looking at the below images previously posted by @paulgdls here and here - first of Ophthalmosaurus icenicus, second of Ichthyosaurus sp. - I'd say that the exoccipital doesn't look like those of ichthyosaurs.

 

 

 

However, looking at the interpreted reconstruction of the back of the skull of Borealonectes russelli from Sato and Wu (2008; Fig. 5), I'd say plesiosaur might be an option. If not, maybe look into crocodile again?

 

[paulgdls]

I would agree bone two looks like an exoccipital-opisthotic of a reptile, possibly a small plesiosaur. I wonder what the same elements look like in mesozoic turtles? There appear to be elements of the semi-circular canal impressions in these bones. 

 

Paul

 

 

[Mike from North Queensland]

@pachy-pleuro-whatnot-odon the thought from the face book site is that. " The main piece is not a vertebra, but the basioccipital and left exoccipital of a reptile, reminiscent of mosasauroids but obviously quite small compared to giant mosasaurs. As far as I know, the only previous vaguely-diagnostic material of this group from Queensland was a single vertebra of a 'dolichosaur " 

 I have not been able to find any images on the internet but based on that I have emailed the palaeontologist from the local museum about the specimen for research and got the out of office reply so another week to wait on a reply. Attached is a composite photo reflecting the two halves to show a more complete image.  

 

[pachy-pleuro-whatnot-odon]

Hi @Mike from North Queensland,

It is possible that the basioccipital is part of a dolichosaur, as they would've been around at the time. However, I don't have any comparison material for this, nor do I have my Halisaurus and Tetisaurus skulls around with me to have a check there. I'd only be able to do so after the 5th of December, when I'm back from abroad. In the meantime, however, you might try to reach out to Dr. Mike Polcyn, who does research on basal mosasauroids and which contact details I'm sure @Jared C will have for you.

[RuMert]

My impression was croc, but I'm not an expert here

[Jared C]

20 hours ago, pachy-pleuro-whatnot-odon said:

however, you might try to reach out to Dr. Mike Polcyn, who does research on basal mosasauroids and which contact details I'm sure @Jared C will have for you

I asked Mike about the basioccipital,and he’s passing it off to a local paleontologist here. Pretty curious about this now- go find the rest of it

Also, 

20 hours ago, pachy-pleuro-whatnot-odon said:

It is possible that the basioccipital is part of a dolichosaur

which dolichosaurs were around in the Albian? My impression was that they showed up in the cenomanian 

[pachy-pleuro-whatnot-odon]

4 hours ago, Jared C said:

I asked Mike about the basioccipital,and he’s passing it off to a local paleontologist here. Pretty curious about this now- go find the rest of it

 

Should still be there after four years of waiting, no sweat! I mean, what's four more years of multiple millions, right? 

 

Quote

Also, 

which dolichosaurs were around in the Albian? My impression was that they showed up in the cenomanian 

 

That's what I thought too. But according to that all-knowing source of information, Wikipedia, the very earliest members of dolichosauridae, such as Kaganaias hakusanensis and (depending on your classification) Tetrapodophis amplectus, were already around during the last stages of the Early Cretaceous, with the former being as early as the Barremian stage. So I guess it also depends somewhat on how you interpret the term "dolichosaur" in the sense of it including or excluding "dolichosaurid"