Pterodactylus scolopaciceps Meyer, 1860 (Pterosauria, Pterodactyloidea) from the Upper Jurassic of Bavaria, Germany: the problem of cryptic pterosaur taxa in early ontogeny.

Steven U. Vidovic,David M. Martill

doi:10.1371/journal.pone.0110646

Abstract

The taxonomy of the Late Jurassic pterodactyloid pterosaur Pterodactylus scolopaciceps Meyer, 1860 from the Solnhofen Limestone Formation of Bavaria, Germany is reviewed. Its nomenclatural history is long and complex, having been synonymised with both P. kochi (Wagner, 1837), and P. antiquus (Sömmerring, 1812). The majority of pterosaur species from the Solnhofen Limestone, including P. scolopaciceps are represented by juveniles. Consequently, specimens can appear remarkably similar due to juvenile characteristics detracting from taxonomic differences that are exaggerated in later ontogeny. Previous morphological and morphometric analyses have failed to separate species or even genera due to this problem, and as a result many species have been subsumed into a single taxon. A hypodigm for P. scolopaciceps, comprising of the holotype (BSP AS V 29 a/b) and material Broili referred to the taxon is described. P. scolopaciceps is found to be a valid taxon, but placement within Pterodactylus is inappropriate. Consequently, the new genus Aerodactylus is erected to accommodate it. Aerodactylus can be diagnosed on account of a unique suite of characters including jaws containing 16 teeth per-jaw, per-side, which are more sparsely distributed caudally and terminate rostral to the nasoantorbital fenestra; dorsal surface of the skull is subtly depressed rostral of the cranial table; rostrum very elongate (RI = ∼7), terminating in a point; orbits correspondingly low and elongate; elongate cervical vertebrae (approximately three times the length of their width); wing-metacarpal elongate, but still shorter than the ulna and first wing-phalanx; and pteroid approximately 65% of the total length of the ulna, straight and extremely thin (less than one third the width of the ulna). A cladistic analysis demonstrates that Aerodactylus is distinct from Pterodactylus, but close to Cycnorhamphus Seeley, 1870, Ardeadactylus Bennett, 2013a and Aurorazhdarcho Frey, Meyer and Tischlinger, 2011, consequently we erect the inclusive taxon Aurorazhdarchidae for their reception.

Highlights

The genus Pterodactylus Cuvier 1809 [1] has a long and complex taxonomic history, and its definition and membership have changed considerably over time
Morphotype one (SMF R 404/BSP AS XIX, SMF R 4072, NHMUK PV R 3949/ OUMNH JZ 1609) consisted of all specimens previously referred to P. kochi possessing a straight rostrum and relatively short cervical vertebrae compared to the P. antiquus holotype
Specimens referred to Pterodactylus antiquus cluster tightly to the regression line, whereas specimens referred to P. kochi are more disparate, but regardless of the spread of data the taxa are well supported by the R2 values

Summary

Introduction

The genus Pterodactylus Cuvier 1809 [1] has a long and complex taxonomic history, and its definition and membership have changed considerably over time. Bennett [2] includes only the type species Pterodactylus antiquus (Sommerring, 1812) [3] within the genus, with which he synonymised Pterodactylus kochi (Wagner, 1837) [4]. Bennett [2] synonymised P. micronyx Meyer, 1856 [5] with Aurorazhdarcho primordius Frey et al, 2011 [6] over which the species name micronyx has priority. He considered Pterodactylus longicollum Meyer, 1854 [7] to be generically distinct and placed it in the new genus Ardeadactylus. Several species of Pterodactylus had previously been synonymised with P. kochi, one of which, Pterodactylus scolopaciceps Meyer, 1860 [8] is discussed here

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