Quadrimaera quadrimana

Maera quadrimana (Dana)

Gammarus quadrimanus Dana, 1853, pp. 955–956, pl. 65, fig. 9.

Maera quadrimana.—Schellenberg, 1938, pp. 45–48, figs. 21–22.—J. L. Barnard, 1955a, p. 13; 1965a, pp. 511–512, fig. 17.

DIAGNOSIS OF HAWAIIAN MALE.—Lateral cephalic lobes softly quadrate, anteroventral corner of head produced as narrow sharp tooth; eyes subcircular, brownish-purple in alcohol; upper lip anteriorly lobate as in “Linguimaera” (Pirlot, 1936); coxa 1 weakly extended, setose and rounded anteroventrally, coxa 2 very narrow anteroposteriorly, anterior coxae lacking posteroventral notch; gnathopod 1 of medium stoutness, article 6 ovatorectangular; palm oblique and convex, equal in length to posterior margin of article 6, defined by tiny cusp and spine, article 5 with several medial rows of diverse setal spines, article 4 lacking posterodistal cusp; gnathopod 2 very large, article 2 with medium-sized anterodistal lobe, article 3 with similar lobe, article 4 slightly extended posterodistally, article 5 very short, with long tumid posterior lobe, article 6 very large, subrectangular, slightly expanded distally, palm transverse, denned by large tooth-bearing spine, tooth adjacent to sharp sinus, palm divided into 3 diverse truncate, spinose processes separated by 2 sinuses, dactyl fitting palm and lacking acclivity; article 2 of pereopods 3–5 narrowly ovatorectangular, with slightly extended, angular posterodistal corners, each with posteroproximal extension; dactyls of pereopods 1–5 with strong distal constriction bearing sharp defining corner and armed with stout seta-bearing flange, sharp nail with large acute accessory tooth, facial setule, constriction also bearing stout setule appressed to margin of nail, locking spines straight and slightly pectinate; articles 4–6 of pereopods 3–5 as in M. pacifica, article 4 of pereopod 3 tumid, of pereopod 4 but especially of pereopod 5 grossly extended posterodistally; pleonal epimera 1–3 with slightly convex posterior margin and small to medium-sized, sharp posteroventral tooth, epimera ventrally spinose, 1–2 with lateral ridges; pleonites dorsally smooth; uropod 3 not exceeding extent of uropods 1–2, rami flat, of medium breadth, apically truncate and spinose, inner ramus very slightly shorter than outer, latter with thin article 2 hidden among spines; telson deeply but not fully cleft, with strongly fixed medial gap, lobes with mediodistal corner unproduced, armed with 4–5 spines, mostly spines as long as or longer than telson.

FEMALE.—Gnathopod 2 slightly smaller than in male, palm slightly scalloped and convex, bearing only incision next to defining tooth; coxa 2 like that of male.

SMALL MALE OF JLB HAWAII 5.—With left male gnathopod 2 like that originally figured by Dana and Schellenberg in which palmar teeth all projecting equally except defining tooth and largest middle palmar teeth only about twice (instead of thrice) as broad as smallest; pereopods 4–5 like those of M. pacifica and not the original M. quadrimana, but pereopods 4–5 slightly more slender than in M. pacifica; telson with strong medial cusp on each lobe; inner ramus of uropod 3 only two-thirds as long as outer ramus, right gnathopod 2 small and plain as if undergoing regeneration.

YOUNG INDIVIDUAL OF JLB HAWAII 14.—Rami of uropod 3 elongate, equal to each other in length.

MALE OF KAWELA BAY.—Article 2 of gnathopod 2 with anterior spines instead of setules, pereopod 5 like pereopod 4 of M. pacifica, with broadly rounded posteroventral corner of article 2.

MATERIAL.—JLB Hawaii 5 (3), 14 (1). Waimanalo, Oahu, 17 April 1951 (4). Kawela Bay, Oahu, 2–7 September 1948 (4).

DISTRIBUTION.—Micronesia, southern Polynesia, Hawaii.