Taxonomy, palaeoecology and biostratigraphy of the Palaeocene teleostean otolith assemblages of the Aquia Formation (Selandian Piscataway and Thanetian Paspotansa members), Maryland, USA, including new genera and species

Extensive collecting of bulk samples at six sites in the Piscataway and Paspotansa members of the Aquia Formation (Palaeocene, approximately 61.0–56.0 Ma based on the upper P3b–P5 and NP5–NP9) in Maryland, U.S.A. resulted in the recovery of 9647 teleostean otoliths, primarily sagittae (99.13%). The assemblage consisted of 20 different teleostean families that represent 23 unequivocal species, four identified to genus, and six assigned to the family level (total of 33 taxa). This makes the Aquia Formation the most diverse and abundant Palaeocene otolith-based assemblage known presently in North America. The otolith assemblage contains two new genera and seven new species. Of special note are Primitivusscomber triangulum and ‘Scomberomorus’ sp. that represent the oldest otolith-based scombrids (family Scombridae) known in the palaeontological record. Percentage similarity measurement indicates that the two Aquia Formation members were extremely alike and represented fish assemblages and palaeoenvironments that were quite similar to one another. The otolith assemblage reveals a palaeoenvironment of mainly normal salinity, marine waters with depths most likely less than 100 m (inner to middle shelf), tropical climate (some indications of possible subtropical climate), soft sea bottoms, and a short surface residence time for the otoliths.urn:lsid:zoobank.org:pub:73342A4B-4CC3-47A8-85D2-0EDC88DD41F5