Tethygeneia elanora J. L. Barnard 1972

Tethygeneia elanora

DESCRIPTION (of female).—Rostrum large, long, curved down, apically blunt, lateral cephalic lobe broad, shallow, quadriform, defined below by weak but sharp incision, anteroventral margin bulbous, rounded; antenna 2 slightly more than half as long as body, antenna 1 only three-fourths as long as antenna 2; eye of medium size, purple core surrounded by 1–2 layers of clear ommatidia in alcohol; flagella of antennae 1–2 each 3 times as long as their own peduncles, flagella thin; accessory flagellum articulate, broader than long, sharply trapezoidal; middle of primary flagellum on antenna 1 with alternate articles slightly swollen or offset and each swollen article bearing 2 aesthetascs; articles of flagellum on antenna 2 even; mandibular molars triturative, each with ragged seta, spine row on right side with 3 main ragged spines, fourth rudimentary spine toward molar, left side with 3 main spines, smaller fourth toward molar, detached thinner fifth spine toward lacinia mobilis, left lacinia mobilis serrate and clearly distinct, right lacinia mobilis appearing composed of 3 parts, as 2 spines and 1 serrate membrane; 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 65 percent as long as article 2, bearing 2 apical spines of medium size, third spine larger, then about 9 smaller proximal spines, and 1 basofacial seta, article 2 with about 10 spines on distal half; lower lip lacking inner lobes, mandibular lobes subtruncate and apically fringed; inner plate of maxilla 1 bearing 1 giant apical seta and 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 1 apicolateral spine separated from 2 medioapical spines by gap and hollow, outer plate with facial setules in 1 even row, article 2 of maxillipedal palp especially broad; coxae 2–3 each with 1–2 posterior setules, posterior lobe of coxa 4 softly rounded; article 2 of gnathopods 1–2 scarcely setose posteroventrally, hands of gnathopods long, thin and rectangular, palms evenly oblique, article 5 of gnathopod 1 about 60 percent length of article 6, about 65 percent on gnathopod 2, posterior margin of article 5 on gnathopod 1 triangulate but softly, on gnathopod 2 produced to long lobe guarding posterior proximal third of hand; locking spines of pereopods 1–2 really thin flexible setae, dactyls each with distal constriction, nail, long sharp inner seta, and shorter sharp facial seta guarding constriction, inner margin of dactyl usually smooth but in enlarged adults occasionally bearing extremely faint, broadly spaced notches resembling incipient castellations; pair of locking spines of pereopods 3–5 normally stiff and slightly thickened, each with subterminal setular trigger, spines often joined by third or fourth member in form of tiny setules, outer apical margin of article 6 at base of dactyl sharply serrate only on pereopods 3–5; coxa 5 evenly lobate, coxa 6 with large quadriform posterior lobe; article 2 of pereopods 3–5 broadly expanded, articles 3–7 slender, article 2 on pereopod 5 lacking facial seta posterior to main ridge; epimeron 1 softly rounded behind, with or without very weak declivity at posteroventral corner, epimeron 2 with sharp shallow tooth and protruding posteromiddle margin, epimeron 3 similar but protrusion deeper and tooth smaller, 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 anterodorsal to base of uropod 3; telson flat, broad, cleft more than halfway, apices broad, blunt, smooth, lateral margins of lobes with 2 pairs of setular sets, occasionally third near base, plus other single setules in tandem (see Figure 121T, upper); cuticle generally clear of setules but rare setule present, crescents absent.

MALE.—Like female but antennae more elongate and no male yet discovered bearing calceoli; eyes slightly larger than in female; accessory flagellum with main elongate spine found in female reduced to size similar to other setae; antennal peduncles developing groups of setules as in T. waminda, formula for aesthetascs and swollen articles generally similar to female; gnathopods enlarged, less elongate, hands broader than in female; posterior setae on article 6 of pereopods 1–2 becoming strongly plumose and elongate, locking setae increasing to 6.

JUVENILES (about 1.3 mm minimum length examined).—Generally like adult female except as follows: flagellum of antenna 1 bearing only 4 articles, articles 2 and 3 each with 1 aesthetasc; accessory flagellum normal; antenna 2 also short, spines and setae everywhere far less abundant; for example, inner plate of maxilla 1 bearing only 1 apical seta and 2 medials, mandibular palp article 3 bearing main spine, 2 apicals and 1 proximal to main, article 2 bearing only 1 spine, right mandible with only 2 main spines, no rudimentary, and lacinia mobilis clearly composed of 2 similar spines partially fused at base, left mandible with 3 spines, ragged seta of molars very short; gnathopods very thin, plain, dactyls overlapping palms (see Figure 121N, lower); pleonal epimera plain, lacking ventral spines (see Figure 121E, lower); outer ramus of uropod 3 clearly biarticulate, this articulation disappearing or becoming very dim in adults; telson with main pairs of setules occurring highly distad in comparison with adult (see Figure 121T, lower).

EXAMPLES OF FLAGELLAR FORMULAE (of males and females).—Female antenna 1 flagellum, segments alternately swollen and bearing aesthetascs in middle, but all proximal segments with aesthetascs and basal-most segment with 2 sets; in following formula, numbers = presence of aesthetascs and, after first few segments, also swollen articles; parentheses = more than 1 set of aesthetascs on a segment: (1–3):2:2:2:2:0:2:0:2(continuing to segment 25; then, as follows, starting with segment 26)2:0:1:0:0:0:0(terminus), swellings diminishing distally.

MALE, NORMAL.—(2–2):2:2:2:0:2:0 (continuing; then, commencing segment 36 as) B:0:B:0:0:0:0:0:0 (terminus). Alternate: 2:2:2:2:2:2:0:2:0:2:0, etc.