Mallacoota subcarinata

Mallacoota subcarinata (Haswell)

Megamoera sub-carinata Haswell, 1880b: 335, pl. 21: fig. 4.—Chilton 1885:1039.

?Moera petriei Thomson, 1882:236–237, pl. 18: fig. 3.—Chilton 1883:82, pl. 2: fig. 4; 1885:1039.

?Moera subcarinata.—Chilton 1885:1039.—Thomson 1889: 261.

?Moera sub-carinata. —Chilton 1884:230–231. —Thomson and Chilton 1886:146.

?Elasmopus subcarinatus.—Stebbing 1888:1019–1025.—Chilton 1892:261.—Walker 1904:275, pl. 5: fig. 34.—Stebbing 1906:441–442.—Walker 1909:335.—Stebbing 1910a:602,643; 1910b: 457–458.—Thomson 1913:243.—Chilton 1915:321–326, figs. 1–6; 1921a:76.—Stephensen 1931:11.—K. H. Barnard 1935:286.—Pirlot 1936:317–326, figs. 136–145.—K. H. Barnard 1937:160–161.

?Elasmopus persetosus Stebbing 1888:1019, pl. 98.

?Maera subcarinata.—K. H. Barnard 1940:460.—Nayar 1967:149.

DIAGNOSIS (of phenotype A).—Head with deep anteroventral notch slightly gaping and lobe ventral to notch thin and not reaching tangent of ocular lobe; article 1 of antenna 1 with 3–5 ventral spines in line and middistal cusp; accessory flagellum 3–4 articulate; eyes black; mandibular palp in adolescence with thin article 1 lacking distal cusp and articles 2–3 of normal proportions, with article 3 bearing 3 subterminal setae and 2 terminal setae, in adults (both sexes) article 1 becoming apically tumid, or in some females only developing weak cusp, article 2 becoming relatively much shorter than article 3, latter with only 2 apical setae; mandibular molar with weak basal hump; each outer lobe of lower lip with 1 medial cone and 1–2 apical cones; inner plate of maxilla 1 (adult) with 5 long plumose apical setae and 5 setules on side, palp apically tapering and bearing spines and setae terminally and halfway along medial margin; inner plate of maxilla 2 bearing only medial setules (hairs); palp article 3 of maxilliped with subfalciform apical process; coxa 1 normally extended forward, anterior margin moderately excavate, posteroventral corners of coxae 1–3 with strong notch in adults (present in juveniles), article 4 of gnathopod 2 with strong tooth in both sexes, female gnathopod 2 of normal dimensions (see “Remarks”), male hand elongate, strongly setose on posterior half of medial margin, palm defined by 1–2 small cusps, distal portion with low spinose, castelliform teeth, dactyl curved, simple or weakly serrate near base on inner margin; pereopodal dactyls with distal constriction marked with 3 setules, locking spines simple; article 2 of pereopod 5 with regularly rounded posteroventral lobe and weak posterior serrations; base of uropod 1 with lateral spine; rami of uropod 3 about 1.4 times as long as peduncle, rami equal to each other in length; adult telson with strongly gaping bifid apices armed with 3 long and 2 very short spines, adolescents with much less gape and shorter wings, with 1 long spine reduced in length and smallest spines occasionally represented by spinule or seta, or absent; pleonites 1–3 dorsally smooth; pleonite 4 dorsally bicarinate (as in M. diemenensis); pleonal epimera 1–2 each with lateral ridge and weak posteroventral tooth, epimeron 3 with small (adolescent) to medium-sized posteroventral tooth, epimera 2–3 with many ventral spines set in single row, but occasional adolescent male with spines set in pairs. Males about 7–12 mm long, females about 7–10 mm long.

PHENOTYPE B.—Like phenotype A, but coxae 1–3 lacking notches in both sexes; male gnathopod 2 in juvenile with palm rudimentarily similar to adult of phenotype A, bearing 1 spine on middle process, in adult male palm with large invagination between distal spinose process and strong simple cusp, palm defined by 1 cusp, dactyl apically acquiring form of adze; male developing 2 or 3 spines in each position on ventrofacial margins of pleonal epimera 2–3; articles 2–3 of male gnathapod 2 with large anterofacial lobes, medial and lateral.

PHENOTYPE D.—Like phenotype A, but cusp absent on article 1 of antenna 1, distal process of palm on male gnathapod 2 small, bulbous, bearing only 2 spines, middle of palm without process, weakly excavate, weak semifacial lobe at apex of dactyl and very weak cusp proximal to dactyl on face of hand, dactyl adze shaped; lobes of articles 2–3 of gnathopod 2 weak as in phenotype A; medial face of hand of male gnathopod 2 very setose like phenotypes A and B (not shown in Figure 145xrN2s); coxae 1–3 each with posteroventral notch.

DISTRIBUTION.—Warm-temperate Australia, littoral and sublittoral; ?New Zealand; South Africa; Indonesia; subantarctica.