Homeoura chelifera (Selys, 1876)

Lozano, Federico, Muzón, Javier & Torres, Sabrina, 2009, Description of the final instar larva of Homeoura lindneri (Ris, 1928) and redescription of the larva of H. chelifera (Selys, 1876) (Odonata: Coenagrionidae), Zootaxa 2231, pp. 47-54 : 49-51

Homeoura chelifera (Selys, 1876)

Acanthagrion ? cheliferum Selys, 1876: 319 –321 (description of male).

Acanthagrion cheliferum: Needham, 1904: 717 (incomplete larval description); Bulla, 1971: 159 –166, figs. 175-182, 246 (redescription of adult and larva; this work was never formally published and the material used is lost). Homeoura chelifera : von Ellenrieder, 2008: 93 (complete synonymy).

Redescription of final instar larva (figs. 3–4). Head. Almost 2.10 times as wide as long at the widest point. Posterolateral margins rounded, with more than 20 spinules. Antennae seven-segmented (the third antennomere is the longest). Mandibular formulae (figs. 3b–c): L 1+2 3 4 5 y a b (80%: 1<3<4<2<5; 20%: 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 (figs. 3a) sub-triangular, ratio of maximum length to maximum width 1.29; anterior margin convex and slightly crenulated; with 6 or 8 premental setae (3+3 or 4+4), the inner ones shorter than 0.5 the length of the external ones, except in one specimen where the inner ones are longer than 0.75 the length of the external ones; lateral margin with 3–5 spines; latero-distal margin with 3–4 spines. Labial palp: outer margin with 5 setae; distal margin with 7–8 teeth (which become smaller to outer margin); movable hook longer than half the length of outer margin.

Thorax. Wing pads reaching anterior third of SIV; femora without spines on flexor margin; with short spines in two rows along the entire extensor margin. Tibiae I–III with short spines restricted to distal third of flexor margin (increasing in number towards tibia III); without spines along extensor margin.

Abdomen. Cylindrical. SIV–VIII with spines along lateral carina; SV–X with a posterior ring of spines. Cerci conical, smaller than 0.5 the length of SX, except in one male exuvia (fig. 4c) in which the cerci were larger. Female gonapophyses (figs. 4a–b) not surpassing distal end of SX, outer ones with a ventral row of denticles. Male gonapophyses (figs. 4c–d) acute, not surpassing distal end of SIX. Lateral caudal lamella (fig. 3d) lanceolate (almost 0.84 the length of the abdomen); ratio of maximum length to maximum width 7.62; nodus at approximately 0.55 of lamella's length; with transverse suture, 15–18 dorsal spines, and 33–36 ventral spines; color pattern very diffuse, with scattered groups of dark branching tracheae. Medial caudal lamella lanceolate (almost 0.86 the length of the abdomen); ratio of maximum length to maximum width 6.94; nodus at approximately 0.50 the length of the lamella; with transverse suture, 25 dorsal spines and 20–26 ventral spines; color pattern similar to that of lateral caudal lamellae.

Measurements (in mm; average, range in square brackets; N=6, unless indicated otherwise). Total length (without caudal lamella) (N=4): 11.56 [11.20–11.90]. Head: maximum length (N=4): 1.38 [1.20–1.50]; maximum width: 2.90 [2.80–3.00]. Prementum: maximum length: 1.90 [1.90–2.00]; maximum width: 1.47 [1.40–1.60]; outer premental seta (N=1): 0.33. Thorax: femur I: 1.50 [1.40–1.60]; femur II: 2.05 [2.00–2.10]; femur III: 2.70; tibia I: 1.93 [1.80–2.00]; tibia II: 2.15 [2.00–2.30]; tibia III: 2.68 [2.50–2.80]; inner wing pads maximum length: 3.50 [3.40–3.60]; outer wing pads maximum length: 3.50 [3.40–3.70]. Abdomen: total length: 7.27 [6.50–7.80]; SIX length: 0.67 [0.60–0.70]; SX length: 0.48 [0.40–0.50]; cerci length: 0.20; female gonapophyses length (N=3): 1.00; male gonapophyses length (N=3): 0.50. Lateral caudal lamella: maximum length (N=2): 6.10 [6.00–6.20]; maximum width (N=2): 0.80; dorsal row of spines length (N=2): 0.80; ventral row of spines length (N=2): 3.35 [3.30–3.40]. Medial caudal lamella: maximum length (N=2): 6.25 [6.20–6.30]; maximum width (N=2): 0.90 [0.80–1.00]; dorsal row of spines length (N=2): 3.10 [3.00– 3.20]; ventral row of spines length (N=2): 3.30 [2.80–3.80].

Specimens examined. Homeoura chelifera : Argentina, Corrientes Province, Ituzaingo Department, San Juan de Poriahú Ranch, 27° 42’ 51’’ S, 57° 11’ 14’’ W; 01/X/2003, coll. J. Muzón, 1 male exuvia (reared) [emergence date not determined]; 2 males and 2 females same data but coll. S.A. Mazzucconi [emergence data not determined except for 1 female: 15/X/2003]; Argentina, Corrientes Province, Mercedes Department, El Dorado Ranch, Corrientes River and artificial channel, 28° 44’ 34’’ S, 58° 07’ 36’’ W; 26/IX/2003, coll. S.A. Mazzucconi, 1 female exuvia (reared) [emergence date not determined].