Records of the Rare Flabby Whalefishes Cetomimus hempeli and Gyrinomimus bruuni (Teleostei: Beryciformes) from Japan

Abstract

Two genera of the poorly known family Cetomimidae (flabby whalefishes), Cetomimus Goode and Bean, 1895 and Gyrinomimus Parr, 1934, are morphologically similar but differ in jaw tooth row (indistinct diagonal rows in Cetomimus vs. distinct longitudinal rows in Gyrinomimus) and vomerine tooth plate morphology (domed, round or rarely oval vs. flat, rectangular or oval). Three examples of these genera, recently collected off the Pacific coast of Honshu Island, Japan, were respectively identified as Cetomimus hempeli Maul, 1969 (two specimens; characterized by a rounded and broad head, a reduced fourth gill arch and small slit between the third and fourth arches, and cavernous tissue present around the anus, 1–3 anal-fin rays, and dorsal fin origin, but absent from the caudal peduncle) and Gyrinomimus bruuni Rofen, 1959 (single specimen; characterized by 20 dorsal- and anal-fin rays, three or four jaw tooth rows, the dorsal-fin base length 18.2% of the standard length, the anal-fin base with lappets, and the lateral-line pores without flaps). Previously, C. hempeli had been known only from the Atlantic Ocean, the present specimens are the first reliable records from the Pacific Ocean, and the specimen collected off the Fukushima Prefecture coast is the northernmost record of the species. The specimen of G. bruuni also represents the first reliable record of this species from Japan, and the northernmost record of the species. New standard Japanese names are proposed for both species, “Seiun-kujirauo” for C. hempeli, and “Hitaguro-kujirauo” for G. bruuni.

Keywords

• cetomimus hempeli
• gyrinomimus bruuni
• cetomimidae
• tohoku district
• kii peninsula
• northernmost record
• range extension
• new japanese name
• coi