A cautionary tail: Cyrtura temnospondyla Jaekel, 1904, an enigmatic vertebrate specimen from the Late Jurassic Solnhofen Limestone

Abstract

POSTPRINTThis is a postprint of the following peer-reviewed publication: AbstractThe enigmatic vertebrate taxon Cyrtura temnospondyla is reassessed following the location and reuniting of both counterparts. The specimen, comprising a series of caudal vertebrae from the Tithonian Solnhofen Limestone, has variously been interpreted as derived either from a temnospondyl amphibian, or a turtle, or to be indeterminate. The redescription of this caudal series reveals that the vertebrae have a single centrum, in contrast to previous descriptions. This specimen is here interpreted to be the tail of a turtle more derived than Proganochelys and Meiolania, but is otherwise indeterminate and cannot be associated with any of the diagnosed taxa from the Solnhofen Limestone. Cyrtura temnospondyla lacks any diagnostic character and must therefore be considered a nomen dubium.This work is licensed under the Creative Commons Attribution 4.0 International License.CC-BY 4.0

A review of the fossil record of turtles of the clade Thalassochelydia

“…In a few studies, thalassochelydian turtles have been found to be closely related to Cretaceous turtles, in particular the Early Cretaceous protostegid Santanachelys gaffneyi Hirayama, 1998 and the Early Cretaceous sandownid Sandownia harrisi Meylan et al, 2000(Hirayama 1998Meylan et al 2000;Joyce 2007;Mateus et al 2009;Sterli et al 2013;Anquetin et al 2015). If these connections are corroborated by future work, Thalassochelydia may become significantly more speciose than presented herein by including species from the Cretaceous and Paleogene.…”

“…The morphology of the basisphenoid in the region of the dorsum sellae is of particular interest for the systematics of the group (see Anquetin et al 2015). All "plesiochelyids" share a unique configuration in which the dorsum sellae is high and does not overhang the posterior part of the sella turcica.…”

“…Courtedoux, Canton of Jura, Switzerland ( Figure 4); Lower Virgula Marls, Chevenez Member, Reuchenette Formation, late Kimmeridgian, Late Jurassic (Comment et al 2011(Comment et al , 2015Anquetin et al 2015).…”

“…Although illustrations were provided by Gaffney ( , 1976, the type material of Plesiochelys planiceps has still not been described in detail in the literature. Without providing such a description, Anquetin et al (2015) Type species. Portlandemys mcdowelli Diagnosis.…”

“…More recently, Anquetin et al (2015) expanded the matrix of Joyce (2007) by including newly developed cranial characters. The resulting phylogenetic analysis, which included Plesiochelys planiceps, Portlandemys gracilis, and Tropidemys langii in addition to the aforementioned taxa, found a monophyletic group uniting "plesiochelyids," Jurassichelon oleronensis, and Solnhofia parsonsi .…”