Thaumatodracon

Thaumatodracon is a relatively large rhomaleosaurid from the Lower Jurassic (Sinemurian) of Lyme Bay – the coast between Lyme Regis and Charmouth – UK. The holotype specimen (NLMH 106.058) is an almost complete skull and cervical (neck) series. It has a 60 cm long skull, and based on comparison with other rhomaleosaurids I estimate its total body length to be 6.5 m. The skeleton was discovered in early 1969 by amateur fossil hunter Kurt Wiedenroth and purchased later that year by the Niedersächsisches Landesmuseum, Hannover (Smith and Araújo, 2017).

Thaumatodracon was described and named by Ricardo Araújo and myself. The skeleton shares some characters with earlier Hettangian rhomaleosaurids (e.g. Atychodracon, Eurycleidus), and other characters with later Toarcian rhomaleosaurids (e.g. Rhomaleosaurus sensu stricto and Meyerasaurus). Its proportions are also intermediate between Hettangian and Toarcian rhomaleosaurids (Smith and Araújo, 2017).

Thaumatodracon has two unique characters (autapomorphies): a pronounced pit on the posterior margin of the dorsal ramus of the squamosal, and a paired anteriorly tapering triangular basioccipital processes, although it is possible these are taphonomic artefacts. It also has the following unique combination of characters.

• Premaxilla-maxilla sutures parallel immediately anterior to the external nares
• Frontals contact on the midline
• Premaxillary rostrum short
• Five teeth in the premaxilla
• Gently rounded medially convex prefrontal-frontal suture
• Articular with prominent dorsally concave medial flange anteromedial to the articular glenoid
• Robust rod-like axis neural spine with circular cross section
• Neural spines expanded distally

Thaumatodracon was a top-predator in its ecosystem, and probably hunted cephalopods, fish, and smaller marine reptiles.

The genus name derives from the greek θαύμα (= thávma), meaning ‘wonder’, and δράκων (= drákon), meaning ‘dragon’. This is an intentional nod to the invalid name ‘Thaumatosaurus‘, which was once used interchangeably with Rhomaleosaurus before I made ‘Thaumatosaurus’ a nomen dubium (see my article about that here). However, I really liked the sentiment behind the name ‘wonder reptile’, so redeployed the ‘wonder’ part for Thaumatodracon.

For more information about Thaumatodracon here is my blog article from when our paper was published in 2017: https://plesiosauria.com/thaumatodracon-the-wonder-dragon/