Comments on the Pteranodontidae (Pterosauria, Pterodactyloidea) with the description of two new species

Abstract

Considered one of the best known flying reptiles, Pteranodon has been subject to several reviews in the last century. Found exclusively in the Upper Cretaceous Niobrara Formation and Pierre Shale Group 11 species have been attributed to this genus (excluding the ones presently regarded as representing Nyctosaurus). While reviewers agree that this number is inflated, there is disagreement on how many species can be identified. The last review recognized only two species (Pteranodon longiceps and Pteranodon sternbergi) both being sexually dimorphic. Based on several cranial features, some specimens previously referred to the genus Pteranodon are re-evaluated leading to the recognition of the following species, two of which new that are described here: Pteranodon longiceps, Geosternbergia sternbergi, Geosternbergia maiseyi sp. nov., and Dawndraco kanzai gen. et sp. nov. They differ mainly by features such as the direction and extension of the frontal crest, the angle and extension of the posterior process of the premaxillae, the shape and extension of the lower temporal fenestra and the length and proportion of the rostrum. The procedures to recognize a pterosaur species are also discussed here, and must take into account primarily morphology, in conjunction with stratigraphic and geographic data. Although well aware that changes in morphology not always reflect taxonomy, the lack of stratigraphic data and the limited number of specimens that can be confidently assigned to one species hampers our understanding on the morphological variations as a function of ontogeny, individual variation and sexual dimorphism. Although the present study has not eliminated the possibility to recognize such differences, caution is needed before models are generalized for pterosaurs.

New long-tailed pterosaurs (Wukongopteridae) from western Liaoning, China

“…Based on the slightly elongated cervical vertebra and the ratio of the wing finger phalanges (with the first one being the smallest), it is tentatively referred to the Wukongopteridae. The two new species described here show that there is considerable morphological variation within the Wukongopteridae and further raise the question if both specimens attributed to Darwinopterus modularis represent the same taxon (see Kellner 2010 for a discussion on the problematic in recognizing pterosaur species). This is particularly of concern since the preparation of the referred (and more complete specimen) was not finished at the time of publication : Fig.…”

A pterodactyloid pterosaur from the Upper Cretaceous Lapurr sandstone, West Turkana, Kenya

“…Exceptions to these isolated discoveries include (1) the Maastrichtian azhdarchid Phosphatodraco, consisting of a semi-articulated series of five cervical vertebrae recovered from the Oulad Abdoun Phosphatic Basin in Morocco (Pereda Suberbiola et al 2003; also see Kellner 2010) and (2) a partial pteranodontoid forelimb from the Cenomanian Hâqel Lagerstätte in Lebanon (Dalla Vecchia et al 2001). …”

Response to Kellner (2017) 'Rebuttal of Martin-Silverstone, E., J.R.N. Glasier, J.H. Acorn, S. Mohr, and P.J. Currie, 2017'

“…In our original paper (Martin-Silverstone et al, 2017), we note that Bennett (1992) focuses on patterns in the data for Pteranodon as a whole, whereas Kellner (2010) focuses on similarities and differences between particular specimens. This difference, between what might be termed statistical and non-statistical approaches, is, in our opinion, the reason behind what Kellner (2017) calls, "the importance of this debate for pterosaur research in general."…”