Middle–Upper Triassic marine vertebrates of Mallorca (Balearic Islands, western Mediterranean)

ABSTRACT

During the Triassic, many groups of predatory marine reptiles appeared and diversified. On Mallorca, fossils of marine reptiles have been found in Muschelkalk (Anisian–Ladinian) and Keuper (Carnian–Norian) facies. Here we describe an anterior caudal vertebra of a basal ichthyosauriform similar to Grippidia (Reptilia: Ichthyosauriformes) from the Ladinian carbonate ramps of the Muschelkalk of Mallorca, which fills a biogeographic gap for the group, hitherto only known from the eastern and western margins of Panthalassa. The most plausible hypothesis to explain the fact that the Mallorcan specimen is younger than all the other related species described so far is supported by a rather isolated condition of the carbonate ramps surrounding eastern Iberia during the Anisian, which might point to a relict character of the Mallorcan species, representing the youngest record of basal ichthyosauriforms to date. Moreover, an epiphysis of an indeterminate reptile and four vertebrae assigned to Nothosaurus sp. (Reptilia: Eosauropterygia) from the Keuper sabkhat provide a new record of the latter genus on Mallorca, which falls within its known distribution area. Therefore, the present work provides an exhaustive review of all the marine vertebrate fossils found so far in the Middle–Upper Triassic of Mallorca, some of them with remarkable palaeobiogeographical implications.

KEYWORDS:

• Muschelkalk
• Keuper
• Balearic Islands
• Eosauropterygia
• Ichthyosauriformes

Acknowledgments

We thank Ryosuke Motani (University of California, Davis) and P. Martin Sander (Rheinische Friedrich-Wilhelms-Universität Bonn) for discussion and most valuable insight on MBCN155. To Joan Arbona (MBCN) for aid in fieldwork and for leading R.M.A. to the sites of Puig d’en Canals and Can Bleda, and for providing insight on local geology. To Salvador Moyà-Solà (ICP) for showing to R.M.A. the Coma Freda site, and for sharing the story of how the Nothosaurus vertebrae were found and collected in the 1970s. To Carol Constantino (MBCN) for access to the fossils of the historical collections of J. Bauzá and G. Colom. To Sebastià Matamalas and Josep Juárez for aid in fieldwork. To Marina Rull and Xènia Aymerich (both ICP) for preparation of the specimens. To Enric Vicens (Universitat Autònoma de Barcelona) for letting R.M.A. use the photographic equipment of the department. To Daniela Schwarz (Museum für Naturkunde Berlin), Rainer Schoch (Staatliches Museum für Naturkunde Stuttgart) and Ingmar Werneburg (Eberhard Karls Universität Tübingen) for access to comparison material in their respective institutions. To Gareth Dyke, editor-in-chief of the journal, Jiandong Huang, editor, and Valentin Fischer (Université de Liège) and an anonymous reviewer for their constructive comments and remarks that improved the initial manuscript. We acknowledge support from the CERCA program (Generalitat de Catalunya, Spain). R.M.A. was supported by the predoctoral grant FPU17/01922 (Ministerio de Ciencia, Innovación y Universidades, Spain) and the grant Synthesys+ DE-TAF-23 (European Commission). J.F. was supported by the Agencia Estatal de Investigación (Spain) and the European Regional Development Fund AEI/FEDER EU, project CGL2017-82654-P (European Union). J.F. is member of the consolidated research group 2017 SGR 086 GRC (Generalitat de Catalunya, Spain). O.O. is member of the consolidated research group 2017 SGR 11666 GRC (Generalitat de Catalunya, Spain).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the European Commission [Synthesys+ DE-TAF-23]; Generalitat de Catalunya [2017 SGR 086 GRC,2017 SGR 11666 GRC]; Ministerio de Ciencia, Innovación y Universidades [FPU17/01922]; Agencia Estatal de Investigación (Spain) and European Regional Development Fund AEI/FEDER EU [CGL2017-82654-P].