OSWALDO MOOSER'S FOSSILS FROM AGUASCALIENTES, MEXICO: A SYSTEMATIC APPROACH TO LOST AND FOUND SPECIMENS

Palaeontology in the state of Aguascalientes (México) has an extensive history dating back to 1799. However, it was not until the 1950s that Oswaldo Mooser began to formally describe the palaeontological biodiversity of the state, together with other palaeontologists such as Walter W. Dalquest, with whom he even described multiple new species from local discoveries. Much of the fossil material collected by Mooser was donated to different scientific collections, but the location of several specimens was never specified, and they were lost for decades, including holotypes. Bibliographic sources were consulted to trace the location of part of the Mooser’s collection. A total of four local, national, and foreign institutions were consulted to examine the palaeontological material, and a compilation of various fossils collected by Mooser in Aguascalientes was made, resulting in 76 original specimens of which nine are holotypes. Additional bibliographic sources were used to describe and reassess some specimens that had not been properly evaluated before. Previously published information of the fossil material was complemented, and the anatomical description of some specimens is also presented for the first time. Twenty new reports of unpublished fossils collected by Mooser are addressed in this work. The data obtained have implications for the evaluation of the examined taxa, as the specimens documented in this study still require intensive and specific analyses that cover aspects of their systematics, evolution, ecology, and natural history. Thus, the present work aims to serve as a basis for future palaeontological studies.