Homeoura nepos (Selys, 1976)

Tennessen, Kenneth J., 2009, (Odonata: Coenagrionidae), Zootaxa 2286, pp. 65-68 : 65-66

Homeoura nepos (Selys, 1976)

Agrion ? nepos Selys, 1876 : reprint 136–137, 139–140 (description of male). Homeoura nepos : von Ellenrieder, 2008: 96 –97 (complete synonymy).

Description of final instar nymph (figs. 1–5). Head. 2.10–2.43 times as wide as long at its widest point. Eyes gray, patterned with 3 rows of dark spots anteriorly and laterally. Postero-lateral lobes rounded, each with at least 15 darkbased, posterior spinules and 10–12 long, fine setae situated more dorsally and anteriorly. Antenna 7-segmented (fig. 1); third antennomere longest (0.37–0.41 mm). Mandibular formula (figs. 2a–b): L 1+2 3 4 5 y a b (1<3<2<4<5) / R 1+2 3 4 5 y a (1<3<2<4<5). Labium: articulation of pre and postmentum between bases of coxae I; prementum sub-triangular (fig. 3a), ratio of length to maximum width 1.17–1.29; anterior margin convex and finely crenulated; usually 3 large premental setae per side, rarely 2, or 2 with a small inner one; lateral margin with 2–5 spinules; latero-distal margin (at base of palp) with transverse row of 3 or 4 pale spinules. Labial palp: dorsal margin with 4 long setae; distal margin between movable hook and distal tooth with 5 (rarely 6) small teeth decreasing in size toward large ventral tooth (fig. 3b); movable hook 0.60–0.65 times length of outer palpal margin.

Thorax. Wing pads reaching anterior margin of S5. Legs pale, femora with a narrow dark band at distal ¾ length; femora I–III with spinules along length of the three longitudinal carinae; tibiae I–III with spinules on carinae also but fewer proximally, distally with ventral patch of bifid and trifid setae.

Abdomen. Cylindrical; S2–8 with 1–7 spinules along lateral carina in a nearly straight row (increasing in number on posterior segments); dorso-posterior margins of S5 and S6 with 1–3 spinules, S7–9 with at least 10 such spinules and S10 with 2–5 spinules confined to median crest (longest 0.07 mm) separated from 12–15 lateral and ventro-lateral spinules (fig. 4). Venter of S1–8 with scattered spinules, less dense medially; venter of S1–7 each with small, dark, rectangular, medio-posterior mark. Cerci sub-conical, 0.51–0.63 length of S10. Tips of female gonapophyses reaching posteriorly nearly to level of cercus tip in nymphs (fig. 4), although in exuviae of 2 reared females only slightly beyond posterior margin of S10 (due to telescoping of S10 out of S9); outer valves with 3 ventro-distal spinules and several long setae at mid-length (fig. 4). Median caudal lamella (fig. 5a) lanceolate, 0.62– 0.88 length of abdomen; widest distal to nodus, ratio of length to maximum width 4.55– 6.79; nodus at approximately 0.48– 0.57 length of lamella; with transverse suture, 19–23 dorsal spines, 10–15 ventral spines, tip bluntly pointed to rounded; prenodal portion dark tan with 4 or 5 small marginal groups of dark, branching tracheae; postnodal portion lighter tan, with three diffuse gray spots not reaching margins and with 4 or 5 small marginal groups of darker, branching tracheae. Lateral caudal lamellae (fig. 5b) lanceolate, 0.63–0.92 length of abdomen; widest distal to nodus, ratio of length to maximum width 4.85–7.78; nodus at approximately 0.48–0.53 length of lamella, tip usually slightly more acute than that of median gill; with transverse suture, 9–15 dorsal spines, 23–30 ventral spines, and color pattern similar to that of median caudal lamella but usually with 6 or more postnodal marginal groups of dark tracheae.

Measurements (males N=4, females N=4). Total length 7.8–9.5. Head length 1.0–1.07, maximum width 2.2–2.5. Prementum length 1.40–1.60, maximum width 1.15–1.25. Femur I: 1.20–1.25; femur II 1.60–1.75; femur III 2.00–2.30; tibia I 1.40–1.60; tibia II 1.65–1.95; tibia III 2.05–2.40. Abdomen total length 5.0–6.5; S10 length 0.36–0.41; cerci length 0.19–0.25. Median caudal lamella length 4.05–5.25; maximum width 0.67–0.98. Lateral caudal lamella length 4.12–5.35; maximum width 0.60–0.90.

Specimens examined. Homeoura nepos : Bolivia, Beni Dept., Cercado Province, Lago Los Lagartos, 4 km N of Loma Suarez, 14° 42' 53"S, 64° 56' 35"W; 22/VIII/2003, coll. K. J. Tennessen, 2 female exuviae (reared) [emerged: 23/ VIII/2003, 25/VIII/2003], 5 final instar nymphs, 1 F-1 nymph; Santa Cruz Dept., Ichilo Prov., pond 2 km S of Buena Vista, 17° 28'S, 63°40'W, 13/XI/1998, 1 male exuvia (reared) [emerged 16/XI/1998], coll. K. J. Tennessen.