Metacrangon ochotensis ( Kobjakova, 1955 )

Komai, Tomoyuki, 2012, 3468, Zootaxa 3468, pp. 1-77 : 11-12

Metacrangon ochotensis ( Kobjakova, 1955)

( Fig. 39)

? Sclerocrangon lomae . — Birshtein & Vinogradov 1951: 359. Not Sclerocrangon lomae ( Schmitt, 1921) .

Sclerocrangon ochotensis Kobjakova, 1955: 235 , fig. 1 [type locality: Ekateriny Strait , South Kuril Islands, 2850 m]; 1958: 221 (list), 224 (list).

Metacrangon ochotensis . — Zarenkov 1965: 1764 (list); Komai 1997b: 670, figs 1F, 9; De Grave & Fransen 2011: 458 (list).

Material examined. Holotype: Ekateryna Strait (between Kunashir and Iturup Islands), South Kurile Islands, 2850 m, 28 August 1948, female (cl 11.5 mm), ZISP 48793 .

Diagnosis. Rostrum triangular with acute tip in dorsal view, slightly ascending, extending as far as antennal teeth of carapace; ventral carina low. Carapace with anterior middorsal tooth narrow styliform, arising slightly posterior to rostral base, overlapping rostrum, tip slightly exceeding rostral tip; posterior tooth slightly hooked, arising at about 0.6 of carapace length; submedian teeth present; orbital cleft present; antennal tooth slightly ascending, acuminate; branchiostegal tooth strong, directed somewhat laterally in dorsal view, slightly ascending in lateral view; branchial carina distinct; branchial region smooth. Abdomen fairly sculptured; anterior four somites each with broad, distinct middorsal carina and broadly elevated posterodorsal margin; first to fifth somites with distinct lateral ridges. First pleuron with subacute ventral tooth, second and third somites with blunt ventral or anteroventral teeth, respectively. Sixth abdominal somite with distinct submedian carinae. Eye about 2.0 times longer than wide; dorsal tubercle rounded; cornea poorly pigmented, width about 0.1 of carapace length. Antennular peduncle overreaching midlength of antennal scale; first segment with very short, blunt distolateral process; stylocerite terminating in short, subacute tooth far falling short of distolateral process of first segment; second segment with short blunt distolateral process directed laterally. Antennal scale 0.6 times as long as carapace, 3.4 times longer than wide; lateral margin strongly concave; distolateral tooth relatively long and narrow, not reaching lamella; lamella strongly produced, tapering distally to rounded distal margin; notch separating distolateral tooth and lamella very deep.

Redescription. See Komai (1997b).

Coloration. Unknown.

Size. The holotype female, a non-spawning molt, has a cl of 11.5 mm.

Distribution. Known with certainty only from the type locality ( Fig. 39); 2850 m.

Remarks. This species is represented only by the holotype. It is characteristic in the M. jacqueti species group in having distinctly delimited middorsal and lateral carinae on the first to fifth abdominal somites and the very deep notch dividing the distolateral tooth and distal lamella on the antennal scale, of them the distal lamella is strongly produced and overreaches the distolateral tooth.

Komai (1997b) suggested that the record of Sclerocrangon lomae (= a junior subjective synonym of Metacrangon procax ) from the Sea of Okhotsk by Birshtein & Vinogradov (1951) might be referable to M. ochotensis .