A giant specimen of Rhamphorhynchus muensteri and comments on the ontogeny of rhamphorhynchines

Abstract

Rhamphorhynchus is one of the best-known pterosaurs, with well over 100 specimens being held in public collections. Most of these represent juvenile animals, and the adults known are typically around 1 m in wingspan. Here we describe a near complete skeleton, preserved partially in 3D, of an animal with a wingspan of around 1.8 m, that is considerably larger than other known specimens, and is among the largest known non-pterodactyloid pterosaurs. This animal shows differences in the anatomy not seen in smaller specimens, revealing details of late-stage ontogeny in this genus. The specimen exhibits a disproportionate reduction in the size of the orbit and increase in the size of the lower temporal fenestra, a reduction in the proportional mandibular symphysis, and unusually laterally flattened teeth, which may point to a changing diet as these animals grew. These features show a transition from smaller to larger specimens of Rhamphorhynchus and also appear in other large specimens of rhamphorhyhchines and point to a consistent pattern in their development.