?Gonostoma dracula sp. nov. (Teleostei, Gonostomatidae) from the Oligocene deposits of the Central Paratethys (Romania): earliest occurrence of the modern bristlemouths

摘要

The Gonostomatidae comprise bioluminescent, meso- to bathypelagic fishes which occur from temperate to tropical climates. The members of this family, most notably Cyclothone spp., represent the most abundant vertebrates on Earth. In the present day fauna, the Gonostomatidae consist of six genera: Bonapartia, Cyclothone, Diplophos, Gonostoma, Margrethia, Triplophos. Although the earliest known gonostomatid, ?Primaevistomias weitzmani, is from the middle Eocene of the Caucasus, the most significant increase in number of individual specimens occurred in the Early Oligocene of the Central and Eastern Paratethys. ?Scopeloides glarisianus represents the most abundant Oligocene gonostomatid species and has been recorded from Switzerland, the Czech Republic, Poland, Romania, Caucasus, and Iran, while specimens of ?Kotlarczykia bathybia are rare, isolated and reported only from Poland and the Czech Republic. In this paper we describe ?Gonostoma dracula sp. nov., which seems to be the earliest fossil species of Gonostoma. The specimens were discovered in the Dysodilic Shale intercalations of the Kliwa Sandstone Formation from Piatra Pinului in the Gura Humorului area, Eastern Carpathians (Romania). ?Gonostoma dracula sp. nov., differs from all extinct and extant representatives of the genus and seems to exhibit a sequence of characters that are problematic among Gonostoma species and that show varying affinities with living representatives, although with some important similarities with G. bathyphilum. ?Gonostoma dracula sp. nov., represents the oldest species to date and the first record of the genus from the Oligocene deposits of the entire Paratethys area. Relevant aspects of paleogeography and paleoecology are discussed.