What Is Prejanopterus?

The Pterosaur That Leaned a Little to the Left
Unlike any other known pterosaur, the toothy rostrum of Prejanopterus curvirostra (Fuentes Vidarte and Calvo 2010 ) curved to the left (in dorsal view). Here it is seen in ventral view curving to the right. This is not an artifact of compression over millions of years because several specimens share this odd trait.

Prejanopterus was the first genus of pterosaur from the Lower Cretaceous of Spain. The specimen is known from more than a dozen broken and scattered elements. The question left by the authors: what sort of “pterodactyloid” is it? They were not able to say. Fortunately the specimen and the paper provide just enough data to reveal a nesting.

Prejanopterus parts to scale.

Figure 1. Prejanopterus parts to scale.

Prejanopterus and Elanodactylus Nest as Sisters
The key to this nesting was the unusual shape of the pelvis. The posterior process of the ilium had an anterior process. The pubis was separate from and longer than the ischium. The acetabulum was relatively large.  Only the Elanodactylus described by Zhou (2009) preserves a similar pelvis. No skull is known for Elanodactylus… perhaps until now.

Fuentes Vidarte and Calvo (2010) followed Andres and Ji (2008) in considering  Elanodactylus a sister to Ctenochasma, but Elanodactylus nests here with Germanodactylus. The pointed, tooth-tipped jaws of Prejanopterus and the fused extensor tendon process* confirm a nesting with Germanodactylus.

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.

* Remember, this is a phylogenetic trait, not a sign of maturation. As lizards, pterosaurs grew by different rules than archosaurs.

References
Andres B and Ji Q 2008. A new pterosaur from the Liaoning Province of China, the phylogeny of the Pterodactyloidea, and convergence in their cervical vertebrae. Palaeontology51: 453–469.
Fuentes Vidarte C and Calvo M 2010.
Un nuevo pterosaurio (Pterodactyloidea) en el Cretácico Inferior de La Rioja (España). Boletín Geológico y Minero, 121 (3): 311-328.  ISSN: 0366-0176
Zhou C 2009. New material of Elanodactylus prolatus Andres & Ji, 2008 (Pterosauria: Pterodactyloidea) from the Early Cretaceous Yixian Formation of western Liaoning, China.Neues Jahr. Geo. Paläo. Abh. (DOI: 10.1127/0077-7749/2009/0022.)

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.