Scythogobius, Schwarzhans & Bratishko & Vernyhorova, 2023

Schwarzhans, Werner W., Bratishko, Andriy & Vernyhorova, Yuliia V., 2023, Approaching the Khersonian Crisis: Fish otoliths from the upper Bessarabian (middle Sarmatian s. l.; Late Miocene) of Jurkine (Kerch Peninsula, Crimea), Palaeontologia Electronica (a 31) 26 (2), pp. 1-15 : 7

Genus SCYTHOGOBIUS n. gen.

zoobank.org/ 46A20282-5726-46BB-A6CE-3557EF595087

Type species. Scythogobius spissus n. sp.

Name. Named after the Scyths, early historic inhabitants of the Crimean Peninsula.

Diagnosis. A fossil otolith-based genus of the family Gobiidae with the following combination of characteristics. The otoliths are moderately elongate (OL:OH = 1.25–1.4) and robust with a flat to moderately convex inner face and a strongly convex outer face (OH:OT = 1.7–2.2). The ventral rim of the otolith is nearly straight, and the anterior and posterior rims are almost vertical with minor indentations at about the level of the anterior tip of the sulcus and the posterior tip of the sulcus. The postdorsal projection is short and not bent outward. The sulcus is relatively small, shallow, smoothened sole-shaped, and only slightly inclined. A subcaudal iugum is not developed.

Discussion. Scythogobius is interpreted as a member of the Ponto-Caspian endemic clade Benthophilini. It resembles otoliths of the extant species of Benthophilus , Caspiosoma , and Anatirostrum in the reduced sulcus morphology and the absence of a subcaudal iugum. In all these genera, however, the sulcus morphology is further altered in shape to a nearly oval sulcus outline and a w-shaped ventral sulcus margin. Moreover, these extant otoliths are usually thinner with a less strongly convex outer face, except for Anatirostrum . Anatirostrum is a deepwater endemic monospecific genus in the southern Caspian Sea Basin and probably represents an autogenic endemic speciation. An otolith of the extant A. profundorum (Berg, 1927) is depicted in Figure 3Z – AB. Its otoliths differ from Scythogobius in the deepened sulcus (vs. shallow) and the smaller size of the sulcus (OL:SuL = 2.75 vs. 1.75–2.15). We therefore consider Scythogobius to be unrelated to Anatirostrum and instead to represent an early endemic lineage during the Bessarabian that did not persist to the present-day Ponto-Caspian goby association.

Species. Scythogobius is a monospecific genus with S. spissus from the Late Miocene (Bessarabian) of Crimea.

Figures

FIGURE 3. Otoliths. A–D Ophichthidae indet. juv., SMF PO 101.337, microfauna sample #20, A = anterior view, B = inner face, C = dorsal view, D = ventral view. E Maeotichthys wilhelmi (Djafarova, 2006), SMF PO 101.338, microfauna sample #20, inner face (reversed), digitally composed from three broken segments. F–Q Maeotichthys salebrosus n. sp., F, I, L, O = inner faces, G, J, M, P = anterior views, H, K, N, Q = ventral views, I–K holotype, NMNH ГКН 5960 079 (reversed), microfauna sample #21, F–H, L–Q paratypes, SMF PO 101.339, microfauna sample #20. R–Y Scythogobius spissus n. gen., n. sp., R, V, W = inner faces, S = dorsal view, Y = ventral view, T, U = posterior views, X = anterior view, R–T holotype, NMNH ГКН 5960 080 (reversed), microfauna sample #20, U–Y paratypes (U–V reversed), SMF PO 101.340, microfauna sample #20. Z–AB Anatirostrum profundorum (Berg, 1927), Recent, Caspian Sea, Gilan, Iran, CMNFI 1999-0023.1, Z = inner face, AA = dorsal view, AB = posterior view.