Pseudonezumia Okamura, 1970

Nakayama, Naohide, 2020, Grenadiers (Teleostei: Gadiformes: Macrouridae) of Japan and adjacent waters, a taxonomic monograph, Megataxa 3 (1), pp. 1-383 : 270-272

Genus Pseudonezumia Okamura, 1970

[Japanese name: Nihon-sokodara-zoku]

Pseudonezumia Okamura 1970a:38 (type species: Pseudonezumia japonicus Okamura, 1970 , by original designation).

Paracetonurus Marshall, 1973:615 (type species: Macrourus parvipes Smith & Radcliffe in Radcliffe, 1912, by original designation).

Diagnosis. Anus immediately anterior to anal-fin origin, surrounded by narrow but distinct periproct. Ventral light organ absent. Infraorbital ridge not connected with preopercular ridge, separated by distinct gap. Pelvicfin rays usually 6 (rarely 5 or 7), fin origin distinctly anterior to vertical through pectoral-fin base. Second spinous ray of first dorsal fin weakly serrated along its leading edge. Head bones weak, but not very flexible. Mouth moderately small, posterior margin of upper jaw not reaching vertical through hind rim of orbit. Nasal fossa small. Chin barbel present. Teeth in narrow tapered bands in both jaw; none especially enlarged. Head completely scaled, but underside of snout narrowly to broadly naked; gular and branchiostegal membranes occasionally with scaly patches. No modified scales along head ridges; tip and lateral angles of snout lacking prominent scutes. Body scales covered with long, erect, needle-like spinules in quincunx order; buttresses of scale spinules well developed; reticulate structure developed over entire surface of unexposed portion. Scales along second dorsal and anal fins not enlarged. Grooved lateral line interrupted, occurring as short segments. Cephalic sensory canals broad, without open pores. Branchiostegal rays usually 7, rarely 8. Body lacking prominent silvery reflections when fresh.

Remarks. The present author is preparing a revision of Pseudonezumia , with which Paracetonurus Marshall, 1973 will be synonymized. The genus currently includes the following five described species: P. cetonuropsis ( Gilbert &Hubbs,1916) confined to Japan; P.flagellicauda ( Koefoed, 1927) distributed in the northeastern Atlantic as well as the Madagascar Plateau in the southwestern Indian Ocean; P. japonica Okamura, 1970 known only from Japan (type species of Pseudonezumia ); P. parvipes (Smith & Radcliffe in Radcliffe, 1912) known from the East Indies (type species of Paracetonurus ); and P. pusilla ( Sazonov & Shcherbachev, 1982) sporadically recorded from the Indo-West Pacific.

Key to species of Pseudonezumia from Japan and adjacent waters

1a Preoral length 26–29% HL; caudal depth at base of 40th analfin ray 24–29% HL......................................... P. cetonuropsis

1b Preoral length 20–26% HL; caudal depth at base of 40th analfin ray 27–34% HL............................................... P. japonica