Achelia borealis (Schimkewitsch 1895)

Achelia borealis (Schimkewitsch)

Ammothea borealis Schimkewitsch, 1895:36–40, pl. 2: figs. a,b; 1907:5–9, pl. 1.

Ammothea borealis var. japonica Losina-Losinsky, 1933:57–59, fig. 9.

Ammothea elongata Hilton, 1942g:96.

Achelia borealis Hedgpeth, 1947:24, 27, fig. 13b; 1949:286–287, fig. 41h–m; 1963:1338.

non Ammothea (Achelia) borealis.—Schimkewitsch, 1930:139–144, figs. 34–37 [= Achelia neotenica Krapp, 1986].

MATERIAL EXAMINED.—Gulf of Alaska, S of Kodiak Island, off Albatross Bank, 55°26′N, 155°26′W, 1271 m, R/V Albatross, sta 3340, 29 Aug 1890 (1, holotype, A. elongata Hilton).

DISTRIBUTION.—Taken sparsely in widely scattered localities around the rim of the northern Pacific, the species is recorded from northern Japan, several places off the Russian Far East coasts, and at Point Barrow in the Arctic Ocean, in 80–175 ft (24–53 m), 175–349 fm (320–638 m), and at various depths within these ranges. This is the first time the species has been recorded in the Gulf of Alaska, where it was collected in about double the maximum depth recorded elsewhere.

DIAGNOSIS.—Similar to Achelia superba: relatively slender habitus, well separated and long lateral processes, a tall ocular tubercle, very long abdomen, moderately long chelifores, and dorsodistal tubercles on lateral processes. Similarities mostly superficial and differences become clear on close comparison. Lateral process tubercles of A. borealis larger and more robust than those of A. superba, latter species with much longer lateral processes and legs, particularly with regard to its long very slender propodus. Palp and oviger segments of A. borealis longer and having different length ratios among segments, chelifores shorter than those of A. superba, and ocular tubercle of A. borealis much shorter than that of Loman's species.

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