Tethygeneia megalophthalma (Haswell 1880)

Tethygeneia megalophthalma (Haswell)

Atylus megalophthalmus Haswell, 1880a: 102–103, pl. 6: fig. 4.

DESCRIPTION (of male, based on one specimen).—Rostrum large, long, down-curved, slightly expanded apically and blunt, lateral cephalic lobe broad, shallow, quadriform, defined below by weak but sharp incision, anteroventral margin bulbous, rounded; antenna 2 about three-fourths as long as body, antenna 1 only three-fourths as long as antenna 2; eye large, purple core surrounded by 1–2 layers of clear ommatidia in alcohol; flagella of antenna 1–2 each about 4.5 times as long as their own peduncles, flagella thin; accessory flagellum completely fused to article 3 of peduncle but with same trapezoidal form seen in T. elanora; middle of primary flagellum on antenna 1 with alternate articles slightly swollen and each bearing 2, occasionally 3, aesthetascs; articles of flagellum of antenna 2 even; calceoli absent; mandibular molars triturative, each with ragged seta, spine row on right with 3 main ragged spines and small fourth toward molar, left with 4 main spines and fifth toward molar, left lacinia mobilis serrate and clearly distinct, right composed of 2 serrate spines, 1 toward molar bearing large unserrate membrane weakly falcate; mandibular palp with article 2 about twice as broad as article 3, latter slightly falcate and nearly 4 times as long as broad, but only about 68 percent as long as article 2, bearing 2 apical spines of medium size, third larger, fourth medium, then about 9 smaller proximal spines and 1 basofacial seta, article 2 with about 7 spines on distal half and proximomarginal seta, article 1 naked; lower lip lacking inner lobes, mandibular lobes subtruncate and apically fringed; inner plate of maxilla 1 bearing 1 giant apical seta and 3–4 smaller medial setae on distal half; inner plate of maxilla 2 apically and subapically fringed with small setae, midmedial margin with 2 enlarged setae in tandem; inner plate of maxilliped with apicolateral spine separated from 2 medioapical spines by gap and hollow, outer plate with facial setules mainly in 1 lateral row, a few scattered toward apex, article 2 of maxillipedal palp especially broad; coxae 2–3 lacking posterior setules, posterior lobe of coxa 4 softly rounded; article 2 of gnathopods 1–2 scarcely setose posteroventrally, hands of gnathopods long, ovatorectangular, posterior margins with stout spines, palms evenly oblique and slightly convex, article 5 of gnathopods 1–2 about 55 percent the length of article 6, posterior margin of article 5 on gnathopod 1 evenly triangulate and protruding, on gnathopod 2 produced to long lobe guarding posteroproximal portion of hand; locking spines of pereopods 1–2 really thin flexible setae, up to 4 in number and posterior setae of article 6 plumose, dactyls each with distal constriction, nail, long sharp inner seta and short sharp facial seta guarding constriction, inner margin of dactyl smooth; pair of locking spines on pereopods 3–5 normally stiff and slightly thickened, each with subterminal setular trigger, spines joined by 2 setae-setules; coxa 5 with posterior lobe slightly larger than anterior, coxa 6 with large quadriform posterior lobe; article 2 of pereopods 3–5 broadly expanded, articles 3–7 slender, facial spines on article 2 of pereopods 4–5 absent or weakly developed anterior to anterofacial ridge; epimeron 1 softly rounded behind, with 1–2 weak acclivities on broad posteroventral margin, ventral margins of epimera lined with spines in sets of singles; no dorsal teeth; uropod 3 lacking any stout peduncular spine; pleonite 6 with row of tiny denticles anterodistal to base of uropod 3; telson flat, cleft more than halfway, apices broad, blunt, fringed, lateral margins of lobes with several paired sets and singles of setules; cuticle on epimera covered with crescent-pits, slits on posterodorsal part of body raised as ridges or scales.

FLAGELLAR FORMULA OF ANTENNA 1 (See T. elanora for symbols).—Left medial, (2–2):2:3:3:0:2:0:2:0:3:0:2:0:2:0:3:0:2:0:2:0:2:0:3:0:2:0:2:0:1.0:0: (and 9 more zeros) (terminus). Right medial: (3–2):2:4:0:2:0:2:0:3:0:2:0:2:0:3:0:2:0:0:0:2:0:1:0:2:0:2:0:2:0:1:0:0(and 5 more zeros) (broken).

ILLUSTRATIONS.—The following parts are similar to illustrations (Figures 119–121) given for T. elanora. new species: head, antenna 1, lower lip, mandibles, maxillae 1–2, maxilliped, coxae 1–2, pereopodal dactyls, uropods 1–3, epimera 1, 2 (5 spines), 3 (6 spines), pleonite 6, and the serrations present on article 6 of pereopods 3–5.

DISTRIBUTION.—New South Wales, intertidal.