The ichthyosaurs of the genus Stenopterygius in the Italian museums: taxonomic identification and morphofunctional analysis

Stenopterygius is a genus of ichthyosaurs that is mainly found in Toarcian (lower Jurassic) strata of central and northen Europe. Stenopterygius fossils coming from the locality of Holzmaden (Württemberg, Southern Germany) are globally renowned for their exceptional preservation state. Hundreds of specimens have been found in the Holzmaden area, and, since the 19th century, museums all over the world have acquired skeletons of Stenopterygius from this locality. Italian museums make no exception: many collections in Italy possess Stenopterygius fossils, including the Collezione di Geologia "Museo Giovanni Capellini", Università di Bologna (MGGC) and the Museo di Storia Naturale, Università di Pisa (MSNUP). Tracing back the history of these specimens led us to the early museological efforts by protagonists of the XIX-XX century palaeontology, such as Leopoldo Pilla, Mario Canavari, Carlo Fornassini, Giovanni Capellini, Bernhard Hauff, Eberhard Fraas and Friedrich von Huene. The aforementioned ichthyosaurs were often left undescribed, and no fotographs of these specimens were taken (even though there are notable exceptions), resulting in these fossils being overlooked by the sacientific community for more than a century. Meanwhile, the taxonomy and systematics of Stenopterygius have dramatically changed over time. Here we provide updated species-level identifications obtained by means of liear morphometrics and cladistics for 19 Stenopterygius specimens (including 4 casts) kept in five Italian museums.