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

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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.
TidsskriftJournal of Vertebrate Paleontology
Udgave nummer2
Antal sider14
StatusUdgivet - 2017

ID: 195154884