Cyclotosaurus naraserluki, sp. nov., a new Late Triassic cyclotosaurid (Amphibia, Temnospondyli) from the Fleming Fjord Formation of the Jameson Land Basin (East Greenland)

ABSTRACT

Cyclotosaurus naraserluki, sp. nov., is a new Late Triassic capitosaurid amphibian from lacustrine deposits in the Fleming Fjord Formation of the Jameson Land Basin in Greenland. It is based on a fairly complete and well-preserved skull associated with two vertebral intercentra. Previously reported as Cyclotosaurus cf. posthumus, C. naraserluki is unique among cyclotosaurs for having the postorbitals embaying the supratemporals posteromedially. The anterior palatal vacuity presents an autapomorphic complete subdivision by a wide medial premaxillary-vomerine bony connection. The parasphenoid projects between the pterygoids and the exoccipitals, preventing a suture between the two, a primitive condition shared with Rhinesuchidae, Eryosuchus, and Kupferzellia. Within Cyclotosaurus, the Greenlandic skull has a distinctive combination of circular choanae (shared with C. ebrachensis, C. posthumus, and C. robustus) and a convex posteromedial margin of the tabulars (also present in C. ebrachensis and C. intermedius). A phylogenetic analysis indicates that C. naraserluki is the sister taxon of the middle Norian C. mordax from southern Germany, with which it shares a pair of premaxillary foramina. Cyclotosaurus is one of the most successful and diverse genera of Late Triassic temnospondyls, with at least eight species reported from middle Carnian to late Norian. Cyclotosaurus naraserluki is the largest amphibian ever reported from Greenland and one of the Late Triassic vertebrates with the highest northern paleolatitude currently known.

http://zoobank.org/urn:lsid:zoobank.org:pub:43AAA541-031C-4EE1-B819-4846EBBD1BBB

SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP

Citation for this article: Marzola, M., O. Mateus, N. H. Shubin, and L. B. Clemmensen. 2017. Cyclotosaurus naraserluki, sp. nov., a new Late Triassic cyclotosaurid (Amphibia, Temnospondyli) from the Fleming Fjord Formation of the Jameson Land Basin (East Greenland). Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1303501.

ACKNOWLEDGMENTS

We thank K. M. Gregersen (MGUH) and N. Natorp (GCMK) for access to the material. We are also thankful to M. Moreno-Azanza (Universidade NOVA de Lisboa/Museu da Lourinhã) for invaluable help and discussion on the phylogeny; A. Luz (Museu da Lourinhã) for the artwork of the skull; O. Rauhut (BSPG/Ludwig Maximilian University) for kindly providing photos of the holotype of Cyclotosaurus ebrachensis; and R. Schoch (SMNS) and F. Witzmann (MB) for useful discussion on cyclotosaur phylogeny and character identification. Finally, we are thankful to T. Sulej (ZPAL), J. Fröbisch (MB), and an anonymous reviewer for useful reviews and for helping to significantly improve the original manuscript.

M.M. is supported by the Fundação para a Ciência e a Tecnologia doctoral fellowship SFRH/BD/99580/2014 (Ministério da Ciência, Tecnologia e Ensino superior, Portugal). M.M. was also supported in visiting museum collections by the 2015 European Association of Vertebrate Palaeontologists Research Grant (EAVP-ERG) and by the 2015 Stan Wood Award of The Palaeontological Association (PA-SW201502). Field work in Greenland by L.B.C. was supported by the Carlsberg Foundation.