The shell and pelvic anatomy of the Late Jurassic turtle Platychelys oberndorferi based on material from Solothurn, Swit
- PDF / 13,954,300 Bytes
- 21 Pages / 595.276 x 790.866 pts Page_size
- 17 Downloads / 164 Views
The shell and pelvic anatomy of the Late Jurassic turtle Platychelys oberndorferi based on material from Solothurn, Switzerland Patrick M. Sullivan1 • Walter G. Joyce2
Received: 13 March 2017 / Accepted: 5 May 2017 Ó Akademie der Naturwissenschaften Schweiz (SCNAT) 2017
Abstract Platychelys oberndorferi is a stem pleurodire from the Late Jurassic of Europe. The majority of informative specimens originate from the Late Jurassic (late Kimmeridgian) Turtle Limestones exposed north of the city of Solothurn, Switzerland, but these findings remain poorly documented despite their global importance for understanding the evolution of pleurodire turtles. The available material of this species from this locality currently consists of five shells, one of which is associated with two cervical and one caudal vertebrae and a second with two caudal vertebrae and a phalanx, and 16 fragments mostly found in close proximity to one another but representing at least two different individuals. The Swiss material documents variation in the shape of the dorsal protuberances formed by the vertebrals, the number of supramarginals, the presence of a preneural, the orientation and lateral contacts of the neurals, fusion of neural VIII with suprapygal I, fusion of suprapygal II with the pygal, and the shape of the anal notch. All documented variation falls within the range of variation observed in material from the Late Jurassic (early Tithonian) type locality of Kelheim, Germany, and their referral to Platychelys oberndorferi is therefore confirmed. The utility of confluent plastral fontanelles in diagnosing the sexes is refuted. However, two specimens document substantial differences in anal notch morphology, which are confirmed to be consistent with sexual dimorphism,
Editorial handling: D. Marty. & Walter G. Joyce [email protected] 1
Department of Geology, Macalester College, St Paul, MN 55105, USA
2
Departement fu¨r Geowissenschaften, Universita¨t Freiburg, 1700 Freiburg, Switzerland
with females having a shallow but broad anal notch framed by rounded xiphiplastral processes, whereas males have a narrow anal notch that is framed by pointed xiphiplastral processes. Keywords Testudines Pan-Pleurodira Platychelyidae Jurassic Morphology Abbreviations BSPG Bayerische Staatssammlung fu¨r Pala¨ontologie und Geologie, Munich, Germany MCZ Museum of Comparative Zoology, Harvard University, Cambridge, USA NHMUK Natural History Museum, London, United Kingdom NMB Naturhistorisches Museum Basel, Basel, Switzerland NMS Naturmuseum Solothurn, Solothurn, Switzerland
Introduction Turtles (Testudinata) are one of the primary clades of extant amniotes with about 350 currently recognized species (TTWG 2014). All phylogenies currently agree that the clade of extant turtles is comprised of two crown clades: side-necked turtles (Pleurodira) with a primary distribution in the southern continents and hide-necked turtles (Cryptodira) with a global distribution (e.g., Crawford et al. 2015). While the cryptodiran stem lineage has an exceptionally
Data Loading...
