A new Iberian pleurosternid (Jurassic-Cretaceous transition, Spain) and first neuroanatomical study of this clade of stem turtles

ABSTRACT

A partial skeleton of a pleurosternid turtle (Paracryptodira), from the Jurassic-Cretaceous transition at the Spanish locality of Ágreda (Moncayo Region, Soria Province), is presented here. Its partial skull represents the third of this lineage to be recognised in the European record, with the previously known specimens corresponding to British species. The specimen of Pleurosternidae studied here is attributed to a new species, Pleurosternon moncayensis. This lineage of stem turtles is identified as the most abundant and diverse group of freshwater aquatic turtles in Europe for the stages adjacent to the Jurassic-Cretaceous transition. Its presence decreased radically at post-Berriasian levels, when freshwater lineages of Eucryptodira, of Asian origin, are identified as the dominant forms at these aquatic turtle faunas. The confirmation of Pleurosternidae as freshwater inhabitants is made here, through the first neuroanatomical study for this lineage. Thus, the neuroanatomical reconstruction of Pleurosternon moncayensis sp. nov. is the first to be carried out for a freshwater stem turtle, and it allows us to identify convergent adaptations with freshwater members of the crown Testudines.

KEYWORDS:

• Tithonian-Berriasian
• European record
• stem Testudines
• Pleurosternon
• new species
• neuroanatomy

Acknowledgments

The authors thank Félix Pérez Lorente (Universidad de La Rioja) and Gloria Cuenca Bescós (Universidad de Zaragoza) for the administrative procedures related to the discovery and deposit of the holotype of the new taxon; José Manuel Gasca (Universidad de Zaragoza) and Penelope Cruzado-Caballero (Universidad de La Laguna) for their participation in some of the tasks related to its storage, conservation, and access; and the editor Gareth J. Dyke and the reviewers Pedro M. Callapez and Ignacio Maniel for comments and suggestions. DC is supported by the Beatriu de Pinós postdoctoral programme (BP2017-00195) of the Government of Catalonia’s Secretariat for Universities and Research of the Ministry of Economy and Knowledge. This study was subsidized in part by the Project CGL2017-85038-P of the Spanish Ministerio de Economía y Competitividad-ERDF, as well as by the Aragón Regional Government (“grupo de Referencia Aragosaurus: reconstrucciones paleoambientales y recursos geológicos”).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Ministerio de Economía y Competitividad [CGL2017-85038-P].