BIOMETRIC ANALYSIS OF FISH REMAINS FROM PALAEOLAKE BOLTYSH (UKRAINE).

The results of the study of the meristic and morphometric characters of complete and fragmentary skeletons of Notogoneus gracilis (Gonorynchidae) and Boltyshia brevicauda (Umbridae) recovered from Paleocene–Eocene lacustrine deposits of the Boltysh impact structure are presented in the paper. Some of the specimens previously assigned to Thaumaturus avitus were re-identified as Boltyshia brevicauda. The meristic characters of the specimens considered are stable in both species and refer to those in the respective type series. A previously unknown caudal fin formula (I 6–6 I) is observed in several specimens of Boltyshia brevicauda. The latter species is characterised by more variable meristic characters compared to Notogoneus gracilis. [ABSTRACT FROM AUTHOR]