Ichthyosaur from Yunnan

[Crazyhen]

This is an unprepped ichthyosaur from Luoping, Yunnnan Province of China.  It measures 70cm in length.  Any idea which species is that?  And the completeness of the fossil?

[Fossildude19]

This looks like an imprint, and maybe 1/2 complete. 

[Ludwigia]

It's hard to tell if there's anything at all under that matrix. And as far as species is concerned, no go there until completely exposed. I'd leave this one be unless it's very inexpensive.

[FossilDAWG]

It's hard to say for sure from the photo if the body region is just an impression (the actual bones were on the counterpart slab) but it does seem that way.  If so, there is nothing to prep.  Even if the bones are there, much of the body is disarticulated. 

 

Don

[pachy-pleuro-whatnot-odon]

I agree with all that has been said above, though I'm not sure whether the skull is just only imprint: there might be some bone still adhering to it. The rest of the body, however, appears to be an imprint, consisting of the thorax, some loose vertebrae and, then, what appears to be the tail section running in the opposite direction, back to the skull. It looks like gastralia were at one point present, but it's hard to tell whether any paddles were, as there doesn't seem to be an imprint of them. This may mean they are actually still present on this slab, covered in sediment and waiting to be prepped. But, more likely, they simply aren't part of the fossil.

 

For an identification we'd need to know the age of the fossil (I'm unfortunately not very familiar with the Chinese deposits), for all I could figure out now (from Wikipedia) is that the slightly red colour of slab indicates a Mesozoic to Paleogene age - something that, whilst excluding the Triassic-period, can be determined with much greater resolution from the fossil itself. Although a paddle would be needed for proper identification, my first guess would be of this being a mixosaurid. Are you sure about this being an ichthyosaur, though? For, the very thin rostrum, deep angular (hind portion of the lower jaw), and dip between the rostrum and the top of the skull look more like Saurorhynchus than ichthyosaurian to me: ichthyosaurs, even juveniles, have a very shallow angular on the mandible, and have a skull that more gradually tapers towards the tip of the rostrum. Compare the images below:

 

Juvenile and neonate Stenopterygius sp. at the Urweltmuseum Hauff in Holzmaden

 

 

 

 

 

 

 

 

 

 

Mixosaurids at the Museo Civico dei Fossili di Besano in Besano

 

 

 

 

 

 

 

 

Saurorhynchus sp. at the Museo Civico dei Fossili di Besano in Besano

 

 

 

 

 

 

 

 

 

Saurorhynchus sp. at the Museo dei fossili del Monte San Giorgio in Meride

 

 

 

 

 

 

 

 

 

Holotype specimens of Early Jurassic saurichthyids,. Figures 1 and 2 from Maxwell and Stumpf, 2017. Revision of Saurorhynchus (Actinopterygii: Saurichthyidae) from the Early Jurassic of England and Germany

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

But beware that the slump in the forehead seen in the specimen being evaluated here also appears to occur in ichthyosaurs, as shown by this small, possibly neonate, Mixosaurus sp. from Monte San Giorgio illustrated in figure 2 of Kolb, Sánchez-Villagra and Scheyer, 2011.

 

[Crazyhen]

Many thanks for the very detailed account and analysis.  You are right. I have checked further, this should be a Mixosaurus.  It was found at Luoping of Yunnan, of Middle Triassic.