A new species of Neovenericor (Bivalvia: Carditidae) from Patagonia (Gaiman Formation, Argentina) and an evaluation of the presence of Neovenericor in the Early Miocene

Among Patagonian Carditidae bivalves, the ‘planicostates’ or Venericorini are a group extensively studied from several points of view. All species of this group were included in the genus Neovenericor. New specimens from the Gaiman Formation (Early Miocene) allow us to describe a new Neovenericor species and to analyse the presence of the group in the Early Miocene of Patagonia within a systematic, phylogenetic, morphometric, and stratigraphic framework. A phylogenetic analysis using 65 terminals and 154 characters, adding to a detailed systematic description, allows us to describe the new species Neovenericor camachoi, based on the presence of large shells with 19–20 radial ribs and small nodules around the lunule, which is covered by the umbo. This species is distinguishable from other Neovenericor, such as N. austroplata and N. paranensis. The morphometric analysis shows a clear separation between N. camachoi and other species and confirms the assignment of the Gran Bajo del Gualicho specimens to N. austroplata. The temporal co-occurrence of two species of Neovenericor during the Early Miocene of Patagonia is determined from stratigraphic data, and a complex evolutionary scenario for the Venericorini lineage is proposed.