Elasmopus hooheno J. L. Barnard 1970

Elasmopus hooheno

DIAGNOSIS OF MALE.—Accessory flagellum 2-articulate; eyes medium in size, not as dark as in E. pocillimanus, with occasional central ommatidium visible, pigment in alcohol brownish-purple; mandibular palp normally falcate (as drawn for E. piikoi); article 5 of gnathopod 1 about 80 percent as long as article 6; anterodistal end of article 2 on gnathopod 2 with slightly beveled corner bearing large spine (s), article 3 weakly lobate, article 5 short, bearing narrow but relatively short, setose posterior lobe, article 6 elongate and slightly tapering, palm oblique and about equal in length to posterior margin of article 6, defined by medium-sized conical cusp, distal end bearing spinose, slightly scalloped protrusion, middle of palm with truncate cusp, dactyl slender, normal, fitting palm; posterodistal end of article 6 on pereopods 1-2 with 1 large striate sabre-spine and 1 straight horizontally striate (“corkscrew”) spine, dactyl subapically constricted, minutely striate, bearing stout seta and 2 setules; locking spines of pereopods 3–5 consisting of 1 slight sabre and 1 straight axially striate spine, dactylar seta with weak flange; pereopods 3–5 bearing a few long setae on articles 2, 4, 5, posterior margin of article 2 of regular dimensions and weakly serrate; coxa 6 with unusually broad and slightly truncate anterior lobe; pleonal epimera 1–2 with lateral ridge, posteroventral corners sharply produced, posterior margins sparsely serrate, epimeron 3 with small cusp at posteroventral corner similar in size to a few posterior serrations, posterior margin nearly straight and posteroventral corner grossly quadrate, epimera bearing ventral spines or pairs of spines, no setae; rami of uropods 1–2 with elongate terminal spines but not unusually so; inner ramus of uropod 3 about two-thirds as long as outer, apex of inner ramus truncate and spinose, apex of outer spinose and bearing minute article 2; telson short, squamiform, lobes weakly excavate apically, each bearing 1 long, 1 short spine.

FEMALE.—Gnathopod 2 like that of E. molokai, but article 6 slightly stouter and palm with several small stout spines, occasionally posteroventral corner of epimeron 3 with notch obsolescent.

HOLOTYPE.—Bishop Museum collections, catalog number 7270, male 4.3 mm.

TYPE-LOCALITY.—JLB Hawaii 17, Kawela Bay, Oahu, intertidal, Sargassum, other algae, rocks, coral, 24 May 1967.

MATERIAL.—Five specimens from the type-locality.

RELATIONSHIP.—This species has approximately the same locking spine formula on pereopods 1–2 and telson as does E. spinidactylus Chevreux, but the dactyls lack castellae and the second articles of pereopods 3–5 are of the regularly ovate, unnotched kind. Male gnathopod 2 is very different from that of E. spinidactylus.

Perhaps this species has its closest relationship to E. molokai because of the total number of similarities (pereopods, telson, e.g.), but the main locking spine on pereopods 1-2 of E. molokai is not a sabre, the eyes are more weakly pigmented, the palm of male gnathopod 2 has no middle tooth, and article 2 lacks large spines.

Terminal males of E. hooheno probably have not been described and may, by indicative relationships, have more strongly serrate and setose pleonal epimera than seen in the present subterminal males.

DISTRIBUTION.—Hawaiian Islands.

Littoral (0 to 30 m); intertidal