Odontomacrurus Norman, 1939

Nakayama, Naohide, 2020, Grenadiers (Teleostei: Gadiformes: Macrouridae) of Japan and adjacent waters, a taxonomic monograph, Megataxa 3 (1), pp. 1-383 : 268

Genus Odontomacrurus Norman, 1939

[Japanese name: Kurobozudara-zoku]

Odontomacrurus Norman, 1939:49 (type species: Odontomacrurus murrayi Norman, 1939 , by original designation).

Phalacromacrurus Maul & Koefoed, 1950:971 (type species: Phalacromacrurus pantherinus Maul & Koefoed, 1950 , by original designation).

Diagnosis. Anus midway between pelvic-fin bases and anal-fin origin, preceded by small dermal window of light organ. Second spinous ray of first dorsal fin smooth along its leading edge. Body deep, well compressed laterally. Snout broadly rounded, barely protruding beyond upper jaw. Mouth large, terminal; posterior margin of premaxillary extending beyond vertical drawn through hind rim of orbit. Chin barbel absent. Posterior margin of gill cover notably incised between opercle and subopercle. Teeth large, fang-like, arranged in 1 distinct row in both jaws. Body scales adherent, covered with long, erect, needle-like spinules in quincunx order; buttresses of spinules greatly developed, connected with those of adjacent spinules; reticulate structure absent. Lateral line short, ending at about level of second dorsal-fin origin. Cephalic sensory pores large, prominent. Swim bladder reduced. Pelvic-fin rays 8–11. Branchiostegal rays 6. Color uniformly black. [From Nakayama et al. (2015b).]

Remarks. Odontomacrurus is a monotypic genus, so far known only from its type species, O. murrayi Norman, 1939 . This species is one of few grenadiers whose vertical distribution is confined to midwater depths of the open oceans ( Marshall 1964, 1965; Marshall & Iwamoto 1973; Iwamoto 1990; Iwamoto & Graham 2001; Nakayama et al. 2015b). Based on only small specimens collected from the northeastern Atlantic, Maul & Koefoed (1950) described Phalacromacrurus pantherinus as a new genus and species of macrourids. However, Marshall (1964) revealed P. pantherinus to represent a juvenile stage of O. murrayi . Odontomacrurus is a distinctive genus that is unlikely to be confused with other genera, owing to its unique morphological characters adapted to pelagic life. Such features include the following: uniformly black color of the body; a long, string-like tail; a large, terminal mouth; sharp, fang-like teeth arranged in one distinct row in both jaws; and prominent open pores along the cephalic sensory canals.