Moroccan fossil (Halisaurus?) - ID

[demalvans]

Hi everyone,

 

I bought this piece long ago and after last move I forgot it in a moving box. I just rediscovered it and I would like to know more about it.

The seller said it was an Enchodus half jaw from Morocco Cretaceous.

 

In my opinion :

 

• this is a real piece but perhaps an assemblage (just hope it is not a a complete Frankensteinsaurus).
• it is not Enchodus but it is definitely some kind of Halisaurus.
• I suspect there is a left dentary (?), a right  surangular (??? probably glued piece) and 2 other bones (underneath the surangular and above jaw).

 

I would be very happy to have your opinion and more information on this piece.

 

Thanks for your help !

 

 

 

[Darktooth]

Definitely not Enchodus. Mosasaur of some kind. I think Halisaurus is a reasonable guess but I am no expert. 

[hemipristis]

Question:  I have seen several specimens like these for auction.  They look in similar condition.  How much of this is 'augmented' or 'created', if any, and how can one tell?

[demalvans]

@ Darktooth : Thanks for your comment. +1 for Halisaurus. I hope an "expert" will confirm.

 

@hemipristis : I ask for my piece so I am not sure I am the good guy to answer. But in my case I think bones are real fossils (it may no doubts for me) but have been reorganised on the matrice.

[LordTrilobite]

It does look like a Halisaurine. @jnoun11 will know more probably.

I don't see any red flags here. This all looks original. A nice jaw and a partial vertebra.

[pachy-pleuro-whatnot-odon]

Hi and welcome from the forum! You've definitely got an interesting piece there! 

 

As you suspected and others have confirmed, this is indeed a mosasaur lower jaw - dentary, splenial and surangular - which can easily be identified as such by its foramina. Moreover, the piece is completely authentic, and can be attributed to Halisaurus arambourgi based on size and tooth morphology (which, by the way, are original with the jaw).

 

The second bone cluster is a bit more difficult to identify due from its amorphous nature, but does, as Olof suggests, appear to be a cluster of vertebrae, which can be identified by their characteristic convex and concave nature (mosasaurs are procoelous).

 

All in all a very nice specimen! 

 

On 5/23/2022 at 10:38 AM, hemipristis said:

Question:  I have seen several specimens like these for auction.  They look in similar condition.  How much of this is 'augmented' or 'created', if any, and how can one tell?

 

So to try and answer your question somewhat (because to do so fully would be way too lengthy and detailed), a first good indicator would be the matrix itself. This typically has all kinds of other bones bits and coprolites in there, as can be seen here. Where the matrix has been augmented with fossils, you can therefore often tell because the added elements have either simply been stuck on or, more commonly, set in specially dug insets, which leave their traces by the immediate surrounding matrix being more homogenous in nature or of slightly different colour. This goes for teeth as well, which are a frequent embellishment to jaws (a practice not restricted to Morocco, though very prevalent there and often poorly done). In those cases, and additional clue can be found in the way the teeth attach to the jaw, where you'd look for an uninterrupted root structure coming out of the jaw and leading into the crown, as is the case here. And while roots are often reconstructed, their shape colour and texture give them away if they are.

 

A general one, of course, is that the anatomy of the bones should match what's know about mosasaurs - something especially true when the bones are jumbled, as this makes it more difficult to follow the anatomy and, consequently, easier to embellish on what's left of it. Conversely, the opposite may also be true, in the sense that if the piece is not perfect - as is the case here, where the lower jaw has come somewhat apart - this might indicate a more honest and genuine specimen, since Moroccan dealers prefer to sell more complete and perfect looking pieces, which would fetch them a higher price.

 

Familiarity with similar pieces found may also help authenticate individual specimens, as it can inform you about any particularities, such as the vertebrae seen here. As it's not uncommon for mosasaurs to be found with their head folded back over their bodies in something akin to what used to be known as the "dinosaur death pose", it's nothing particularly remarkable to see vertebrae so close to skull elements, especially it if those vertebrae are cervicals, as seems to be the case here, based on the wide (rather than more rounded) anterior articulation of one of them.

 

A final note should be made that, while I've not been to the Moroccan phosphate mines myself, various others that have, have informed me that mosasaur remains - even articulated pieces - are not particularly rare in the right layers. Small near-articulate specimens like these should therefore not be considered anything too much out of the ordinary (this in stark contrast to the occurrence of mosasaurs in certain other parts of the world, such as in Europe, for instance).

Edited May 25, 2022 by pachy-pleuro-whatnot-odon

[jnoun11]

hi

no red flag

halisaurus maxillary with the surangular one atlas vertebrae and probably the axis. and under the surangular one apophysis.

[demalvans]

Thanks all for your detailed comments and informations.

It is really nice you spend time to answer me.

[Tidgy's Dad]

Nice looking piece.