A new genus of cutlassfish from the Upper Paleocene of Turkmenistan (Scombroidei: Trichiuroidea)

Abstract. A new genus and species of Trichiuroidea, Argestichthys vysotzhyi gen. et sp. n., is described from the Upper Paleocene (middle part Danata Formation) of Turkmenistan. This genus is characterised by several unique derived characters in the structure of body lateral-line system, axial skeleton and jawq dentition, and similar to the Trichiuridae in several advanced characters (single supernumerary spine on first anal pterygiophore, extremely reduced supraoccipital crest, and presence of a pair of anteriorly directed canines on premaxillary). Many primitive characters of the new genus (body shape, low number of vertebrae, structure of suspensorium, opercular series, unpaired fin girdles, etc.) do not occur in the Trichiuridae, but are shared by the new genus with Gempylidae. The new genus also resembles the gempylid Ruvettus in the abdominal position of the first two anal pterygiophores. Therefore, Argestichthys is placed in Trichiuroidea incertae sedis.