A NEW GENUS OF STOMIIFORMS (PISCES, ACTINOPTERYGII) FROM THE EOCENE OF THE NORTHERN CAUCASUS

Abstract

The earliest member of the family Gonostomatidae sensu stricto, Primaevistomias weitzinani gen. et sp. nov., is described from the Middle Eocene (Kuma Regional Stage) of the Northern Caucasus based on the finds of complete skeletons. Sharing synapomorphic characters of the family (shortened premaxilla and jaw teeth widely varying in size), the new form is most generalized among other members of the Gonostomatidae sensu stricto and is characterized by a moderately reduced premaxilla, short anal fin, and nonelongated vertebral centra. The presence of the mesopelagic gonostomatids in the Kuma Fauna indicates good oxygenation within at least 300-600 m of the upper water layers. The finds of complete skeletons of fossil gonostomatids are briefly reviewed.