On a New Species of Venericardia From the Lower Eocene in Northeastern Mexico (Difunta Group)

Venericardia (Venericor) elongata, n. sp., from the lower Eocene of northeastern Mexico, associated with Venericardia (Venericor) planicosta and Turritella mortoni postmortoni, is the first fossil described from the Adjuntas Formation. The paleoenvironmental analysis suggests lhal conditions of geographic isolation were propitious for the speciation of this locally distributed species.