Diversity of gobioid fishes in the late middle Miocene of northern Moldova, Eastern Paratethys-Part II: description of †Moldavigobius helenae gen. et sp. nov.

The middle Miocene (upper Serravallian, lower Volhynian) deposits at Karpov Yar near Naslavcea, northern Moldova, are among the few settings in which fossil fish are preserved with otoliths in situ. Here, we describe the new gobiid dagger Moldavigobius helenae gen. et sp. nov. from this locality. The taxon is characterized by small size (up to 34.2 mm SL), a compact body (body depth 17-21% SL), a fan-shaped caudal fin, large ctenoid scales (< 30 scales in the longitudinal row) and nearly square otoliths (sagittae) with a slender, shoe sole-shaped sulcus. It has 27 vertebrae, six spines in the first dorsal fin, one spine and 11 soft rays in both the second dorsal and the anal fin, 15-17 pectoral-fin rays, and 17 (9/8) segmented caudal-fin rays. The meristic characters of dagger Moldavigobius gen. nov., together with its sagitta shape, suggest a relationship with Lesueurigobius Whitley, 1950, but its fan-shaped caudal fin and the unique sulcus contour of the otoliths preclude its attribution to that genus. In addition, we re-assign an otolith-based species previously described as Knipowitschia suavis Schwarzhans, 2014 as a second member of dagger Moldavigobius gen. nov. Accordingly, dagger Moldavigobius gen. nov. was represented by at least two species in the Serravallian of the Eastern Paratethys (dagger M. helenae gen. et sp. nov., dagger M. suavis nov. comb.). Moreover, dagger M. suavis is also known from the Serravallian ichthyofauna of the SE Mediterranean. dagger Moldavigobius gen. nov. thus demonstrates the key role of fossil skeletal material with otoliths in elucidating the ancient diversity of the Gobioidei.