First Middle Jurassic record of Saurichthyidae (Actinopterygii)

摘要

Saurichthyidae, a speciose group of Early Mesozoic actinopterygian fishes, was previously documented as ranging from the Late Permian to the end of the Early Jurassic. Saurichthyids were most diverse in the Triassic: only two species persisted into the Early Jurassic, restricted to marine sediments in Europe and North America. Here, I report previously undescribed specimens from the Middle Jurassic of the District of Goppingen, Baden-Wurttemberg, Germany. The new material consists of a partial skull, and a second skull with associated lower jaw, both from lower Aalenian sediments of the marine Opalinuston Formation. Although poor preservation prevents referral to species, these specimens are consistent with the Early Jurassic taxon Saurorhynchus based on the elongate jaws anterior to the orbit, organization of the dentition, and structure and ornamentation of the lateral mandible. These finds extend the stratigraphic range of Saurichthyidae into the Middle Jurassic, eliminating any connection between the extinction of this family and the early Toarcian Oceanic Anoxic Event and supporting minimal faunal change across the Toarcian-Aalenian boundary.