Tethysaurus, the odd mosasaur

Tethysaurus nopscai (Bardet et al. 2003) is a mosasaur of the Early Turonian (Late Cretaceous) from Morocco. Wiki puts its length at about 10 feet (3 meters), but the skull here is less than a foot long. I haven’t seen a complete specimen yet.


Figure 1. Tethysaurus based on and the private specimen shown below. Click to enlarge.

Haven’t seen the limbs either. 
I’m not able to make out limbs in the specimens I’ve seen (Fig. 2). Other mosasaurs have large paddles, but Aigialosaurus, a closer relative, has relatively smaller paddles.

The large reptile tree nests Tethysaurus with Aigialosaurus and both with Varanus, distinct from Adriosaurus and the origin of most snakes and Lanthanotus and the origin of pipe snakes. So the small forelimbs appear by convergence with pre-snakes.


Figure 2. Tethysaurus prepared by the Fossil Shack, image from Wiki. Click to enlarge.

Seems like one to several Tethysaurus specimens are known from the private market (Fig. 2). That doesn’t matter to me. I’d like to see more data on the tail and hind limb if possible.

Thanks to Chris Collinson for alerting me to the mistake I had made earlier based on a mislabeled metriorhynchid crocodilomorph (deleted now). The lateral and dorsal views I reconstructed were based on the skull presented by Bardet et al. (2003).

As always, I encourage readers to see specimens, make observations and come to your own conclusions. Test. Test. And test again.

Evidence and support in the form of nexus, pdf and jpeg files will be sent to all who request additional data.

Bardet N, Pereda Suberbiola X and Jalil N-E 2003. A new mosasauroid (Squamata) from the Late Cretaceous (Turonian) of Morocco. Comptes Rendus Palevol 2:607-616.


5 thoughts on “Tethysaurus, the odd mosasaur

  1. The specimen you are using in your reconstruction is a Metriorhynchid, not Tethysaurus. And there’s no way you could derive that lateral reconstruction, clearly a veranoid morphology, from that dorsal view of the specimen which is obviously crocodilian.

  2. I recently bought a tethysaurus skull and wanted to reconstruct it. I haven’t been able to find really good pictures or diagram of what a complete skull or complete (as much as possible) skeleton would look like. I have very little experience and any help would be great?

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