Barnardomelita matilda (J. L. Barnard 1972)

Melita matilda

DESCRIPTION.—General morphology like that of Melita awa J. L. Barnard (in press) from New Zealand; following illustrations or description therefore not replicated; urosome, uropods 1–3, pleonal epimera 1–2, lower lip, body of mandible, maxillae 1–2, maxilliped, articles 1–5 of gnathopod 1, and pereopods 1–2; anteroventral cephalic notch evenly quadrate; eyes black, ovatocirculate; accessory flagellum about 5-articulate; length ratio of articles 2–3 of mandibular palp 15:17, article 3 with 2–4 distal setae and 0–1 seta on middle margin, article 2 with 1–5 setae; maxillipedal palp article 3 with truncate distal margin; gnathopod 1 alike in both sexes, hand distally expanded, palm transverse, convex, dactyl fitting palm and not basally swollen; female gnathopod 2 like that of M. awa, but process on article 4 sharper and spines defining palm longer; male gnathopod 2 with sharp process on article 4, hand broadest in middle, palm oblique, bearing 2 weak invaginations in middle, 1 armed with lateral spine, medial face of hand with deep hollow of small area near palm, defined posteriorly by 2 large spines, anteriorly by subconical cusp, dactyl swollen at base, basolaterally with tuberosity, overriding palm onto face of hand; coxae 1–4 shorter than in M. awa and bearing elongate setae; female coxa 6 like that of male; article 2 of pereopods 3–5 subrectangular, article 2 of pereopod 5 scarcely broader than in pereopod 4, posteroventral corners of article 2 subquadrate, pereopods 3–5 with long setae on articles 4–6 and on article 2 of pereopod 3, dactyls as figured; pleonal epimera 1–3 with lateral ridge, 1–2 with small posteroventral tooth, 3 with large tooth, 2–3 with anteroventral spine in male, only 3 with spine in female, all epimera with 2 weak serrations on posteroventral margin near tooth; pleonite 5 with 1 weak dorsal cusp on each side, each cusp with large spine; uropods 1–3 like M. awa, but uropod 3 lacking ridge on peduncle joining spine bundle; telsonic apices sharp, bearing lateral group of 2 spines, medial group of 2–3 spines. Name represents type-locality as noun in apposition.

HOLOTYPE.—WAM, male, 8.9 mm.

TYPE-LOCALITY.—RLB Australia 19, Matilda Bay, Swan River, Western Australia, in dead clam, collected by Robert L. Barnard, 24 July 1968.

RELATIONSHIP.—The closest known affinities of this species lie with the estuarine Melita awa from New Zealand. The special resemblance occurs in the ornament of pleonite 5, the general morphology of the head and gnathopods, and the pleonal epimera 1–2. Melita matilda differs from M. awa in: (1) the large tooth of epimeron 3; (2) the smaller and deeper pocket on the hand of male gnathopod 2, with basally swollen dactyl; (3) the absence of a hump on the hand of male gnathopod 1; (4) the thinner article 2 of pereopod 5; (5) the absence of a deep anterior hook on female coxa 6; (6) the elongate setae of the pereopods and antennae; (7) the short coxae and their long setae; (8) the lateral ridge of epimeron 3; (9) absence of peduncular ridge on uropod 3; (10) slightly different striation pattern on pereopodal dactyls (see Figure 136D5); (11) spines and setae on peduncle and base of outer ramus on uropod 3 about twice as long as those on M. awa; (12) sharper cusp on article 4 of male and female gnathopod 2; and (13) article 3 of mandibular palp longer than article 2.

The dactyl of male gnathopod 2 (Figure 137N2) in terminal adults is turned so that its anterior margin points medially; it has been slightly flattened in the drawings. Hands of juvenile males have the medial gnathopodal pocket appearing similar to that of adults.

See Melita oba, to follow, for further comparisons.

MATERIAL.—Type-locality (16); JLB Australia 1 (25); Prince, Swan Basin (18).

DISTRIBUTION.—Swan River, Western Australia, in salt water.