| Remarks |
Abstract: Spicomacrurus, formerly classified as a subgenus of Hymenogadus, is elevated to full generic status after the discovery of two new species from the southwestern Pacific. The following synapomorphies characterizing the genus are not shared with either Hymenogadus or Hymenocephalus, although Spicomacrurus obviously belongs within this clade of grenadiers: net-like pattern of black epithelium covering gular region; elongate posterior dermal window of light organ; membranous flange on distal portion of outer pelvic fin ray; and protruding snout formed by three broad horizontally flattened processes of the nasal bones. Spicomacrurus dictyogadus sp. nov. is described from one collected off Vanuatu in 657-685 m. It can be distinguished by its relatively deep and compressed body and head, greatest body width about 2 times into greatest depth; suborbital depth about 3.5 into orbit diameter; and scale rows below origin of second dorsal fin 5½. Spicomacrurus mccoskeri sp. nov. is described from six specimens collected off Chesterfield Plateau in 650-710 m. It can be distinguished by its shallow, cylindrical body and head, greatest body width slightly less than greatest depth; suborbital depth 5-6 into orbit diameter; and scale rows below origin of second dorsal fin 3½. A key to all four species of Spicomacrurus is provided.
This genus is distinguished by the following characters: 7 branchiostegal rays; anus and urogenital pore situated within a small periproct area that lies immediately before anal fin; so-called 'ventral striae' of Gilbert and Hubbs (1916:186) 'consisting of fine parallel lines of dark, alternating with silvery pigment' associated with a light-producing function (Cohen 1964:406-409) on abdominal wall, parts of chest, and shoulder girdle; a small, elongated, translucent lens of the light organ immediately anterior to anus; a small, round, sometimes indistinct lens mesially on chest slightly anterior to a transverse line connecting anterior ends of pelvic-fin bases; the gular region covered with fine black strands of epithelium in a net-like pattern, the whole resting upon underlying layer of dermis; nasal bones forming broad, horizontal, lateral, and medial processes; nasal bones of both sides in broad contact or widely separated by rostral cartilage; serrations absent on leading edge of spinous dorsal-fin ray; 8-10 pelvic fin rays, outer ray greatly elongated, flattened with narrow ribbon-like flange on free distal portion, penultimate portion sometimes more-broadly expanded; short barbel but well developed; gill membranes narrowly attached to isthmus, with a narrow free fold; opercular opening extending forward to vertical under or slightly anterior to posterior margin of orbit; gill rakers on short, slightly raised bases, 12 or fewer on inner side of first arch, less than 14 in total; teeth small, conical, in long narrow bands in both jaws; teeth sharply pointed or bluntly flanged; large scales, highly deciduous, of 'Hymenogadus-type', with complete concentric rings and radial grooves basally, and exposed fields either covered with short, sharp, conical, recurved spinules or lacking spinules (other characters in Okamura 1970:63-64) (Ref. 83327).. |