New data on the shell anatomy of Selenemys lusitanica, the oldest known pleurosternid turtle in Europe

Abstract

One of the most diverse turtle lineages in the Upper Jurassic and Lower Cretaceous record of Europe is that of the stem turtles Pleurosternidae (Paracryptodira), also distributed in North America. The oldest European representative of this lineage is the Portuguese Selenemys lusitanica, known from upper Kimmeridgian to lower Tithonian levels (Late Jurassic). The information on the shell of this taxon is so far very limited, being exclusively restricted to that provided in the publication in which the taxon was defined. New specimens from several upper Kimmeridgian to Tithonian localities in the Consolação Sub-basin of the Portuguese Lusitanian Basin, both from the Leiria District and the Lisbon District, are studied here. They include the most complete shell of the species found so far, as well as several isolated plates that allow us to improve knowledge about it. Thus, new information about the shell anatomy of Selenemys lusitanica is provided, but also about its intraspecific variability.