Spicomacrurus mccoskeri Iwamoto, Shao & Ho, 2011

Schwarzhans, Werner, 2014, Head and otolith morphology of the genera Hymenocephalus, Hymenogadus and Spicomacrurus (Macrouridae), with the description of three new species, Zootaxa 3888 (1), pp. 1-73 : 22-23

Spicomacrurus mccoskeri Iwamoto, Shao & Ho, 2011

Figs. 3G–H , 4C–D , 5

Spicomacrurus mccoskeri Iwamoto, Shao & Ho, 2011: 523 (type locality: 19°45’S, 158°45’E). Material examined. 1 specimen MNHN 1994-0881 (paratype), 173+ mm TL, 19°43’S, 158°48’E, 710 m.

Diagnosis. Pelvic fin rays 9; nasal bones broadly separated by rostral cartilage, forming three horizontal plate like processes; barbel short, 12% HL, reaching only to vertical through anterior part of orbit; interorbital width narrow, 25% HW; OL:OH = 1.95.

Comparison. Spicomacrurus mccoskeri is readily recognized by the slender head (head length: height = 2.3), the narrow interorbital width (25% HW), the broad rostral cartilage, which it shares with S. dictyogadus and the elongate otolith (OL:OH = 1.95).

Description. Head morphology ( Fig. 3G–H ): Head length to height about 2.3 with relatively firm head bones and platy spatulate nasal bones mesial separated by rostral cartilage. No scale pockets visible on head. Snout length 25% HL, orbit diameter 30% HL, interorbital width 25% HW. Barbel 12% HL, reaching vertical through anterior part of orbit. Infraorbital, supraorbital and preopercular canal systems narrow with widths <10% HL, covered by rather thick, firm skin. Infraorbital supporter visible through skin cover. No pores visible. Preopercular angle broad, slightly expanded.

Otolith morphology ( Fig. 4C–D ): Thin and very elongate otoliths with slightly convex inner and slightly concave outer face. OL:OH = 1.95; OH:OT = 4. Predorsal lobe moderately developed, narrow; ventral rim shallow; anterior tip blunt, posterior tip moderately pointed. Sulcus slightly supramedian with narrow, ventrally indented collum. Colliculi large, reaching close to anterior and posterior rims of otolith, caudal colliculum slightly longer than ostial colliculum (CCL:OCL = 1.3); pseudocolliculum indistinct, short; TCL:PCL = 12. Dorsal depression large; ventral furrow distinct, posteriorly reaching towards tip of caudal colliculum.

Distribution. ( Fig. 5 ) Known only from off the Chesterfield Plateau, Coral Sea.

Figures

FIGURE 3. Heads of the species of Spicomacrurus: A–B—Spicomacrurus dictyogadus, holotype, MNHN 2009-1455, redrawn from Iwamoto, Shao & Ho (2011), A—Lateral view, B—Dorsal view. C–D—Spicomacrurus adelscotti, WAM P.28073-004, C—Lateral view, D—Dorsal view. E–F—Spicomacrurus kuronumai, E—Lateral view, NSMT P46796, F—Dorsal view, NSMT P103488. G–H—Spicomacrurus mccoskeri, MNHN 1994-0881, G—Lateral view, H—Dorsal view.

FIGURE 4. Otoliths of the species of Spicomacrurus: A–B—Spicomacrurus adelscotti, WAM P.28073-004, A—Inner face, B—Ventral view. C–D—Spicomacrurus mccoskeri, MNHN 1994-0881, C—Inner face, D—Ventral view. E–G—Spicomacrurus kuronumai, E–F—NSMT P46796, E—Inner face, F—Ventral view, G—NSMT P103488, inner face.

FIGURE 5. Geographical distribution of the species of Spicomacrurus.