Posophotis seri J. L. Barnard 1979

Posophotis seri

DIAGNOSIS.—Accessory flagellum composed of 2–3 long articles possibly tipped by minute fourth. Coxae of elongate form as in Photis, coxae 1–2 longer than broad but slightly shorter than coxae 3–5, latter as long as coxa 4, coxae 3–4 of male only expanded in middle; stridulation ridges absent everywhere. Article 5 of gnathopod 1 longer than article 6, palm oblique and weakly excavate, poorly defined but with 2 widely spread defining spines, dactyl overlapping defining spines. Male gnathopod 2 small, article 2 not lobate, article 5 large, weakly lobate, article 6 broad, only 1.4 times as long as article 5, palm oblique, bearing 1 sinus and weak defining tooth, dactyl not reaching apex of palm; female gnathopod 2 with deep palmar excavation guarded by tooth bearing large spine, dactyl overreaching palm. Article 2 of pereopod 3 very broad and grossly lobate posteroventrally, of pereopod 4 narrower and unlobate, of pereopod 5 scarcely expanded and unlobate; article 4 of pereopod 3 expanded and strongly spinose posteriorly, of pereopods 4–5 narrow and poorly spinose; locking spines composed of 1 long and 1 short simple spines; dactyls simple. Epimera 1–3 almost evenly rounded posteriorly, posteroventral corners with weak notch and setule, epimeron 3 with additional setule and notch, these together not contiguous. Peduncle of uropod 1, but not uropod 2, with long interramal tooth, outer rami of both pairs shorter than inner rami, spines not heavily thickened. Peduncle of uropod 3 elongate, rami styliform, rami shorter than peduncle, outer ramus bearing 3 thick marginal spines, apex lacking article 2, bearing 2 spinules, inner ramus of female as long as outer ramus, inner ramus of male about 65 percent as long as outer ramus, with 1 subapical spine in male, 3 marginal spines in female (mixed on opposite margins). Telson trapezoidal, apex broad, with ventroapical protrusion and apicodorsal excavation marked by 2 large dorsal spines, 1 apicolateral setule each side, 2 minute apicolateral knobs each side, with pair of penicillate setules each side in middle.

DESCRIPTION.—Upper lip with ventral notch; incisors of mandibles with 5 teeth, right lacinia mobilis bifid, spine row with 3 spines, molar with large flake and long seta, weakly triturative at cutting edge, left mandible with 4 spines, no flake or seta on molar; lower lip as shown for Photis reinhardi by Sars (1895, pl. 202) but mandibular lobes sharper; maxilla 1 as shown by Sars, outer plate with 11 spines but inner plate lacking seta, palp with 5 spines and 4 setae (both sides); maxilla 2 as shown by Sars, inner plate with submarginal oblique setal row medially; maxilliped as shown by Sars except for palp article 4 illustrated herein, inner plate with 3–5 stout apical spines, 1 medial locking spine and about 7 terminal and 5 medial setae, outer plate with about 6 medial and 4 apical spines and setae.

VARIATION.—Galapagan males have inner ramus of uropod 3 as long as that of female.

ILLUSTRATIONS.—Gnathopod 1 enlarged greater than gnathopod 2; female pereopod 4 like that shown for male; only terminal male lacking pereopod 5 but presumed to resemble that of female illustrated herein; two main setae of uropod 3 elongate but appearing short and stout in illustration.

HOLOTYPE.—USNM 149507, male “a,” 3.12 mm (illus.).

TYPE-LOCALITY.—SCO 10, Gulf of California, Puerto Peñasco, 23 February 1971, intertidal, Sargassum sp.

VOUCHER MATERIAL.—Type-locality, female “w,” 2.77 mm (illus.): SCO 19, female “f,” 2.70 mm (illus.).

MATERIAL.—SCO 1, 10, 18, 19, 21; KNO 1; GAL 101, 105, 106, 107, 118, 120; DAW 1, ?3, 4, 5, 6, 9, 20, 21, 26, 28, 31, 33, 35, 36, 38, 40; PAN 14.

DISTRIBUTION.—Gulf of California at Puerto Peñasco, Bahía Kino, 0 m; Galapagos Islands, 0–6 m; Panama, 0 m.

Rudilemboides J. L. Barnard