Acanthagrion lancea Selys

Anjos-Santos, Danielle, Carriço, César, Costa, Janira Martins & Santos, Tatiana Chrysostomo, 2011, Description of the final instar larvae of Acanthagrion gracile (Rambur) and Acanthagrion lancea Selys (Odonata: Coenagrionidae), Zootaxa 2832, pp. 44-50 : 45-46

Acanthagrion lancea Selys

Description of last instar larva (figs. 8–14). Head. Almost two times as wide as long, posterolateral margins slightly concave, posterior angle with several short spines ( Fig. 8 ). Posterior margin concave. Seven spines on inferior border of eyes near maxillae. Antennae 7-segmented, the third antennomere the longest. Labium reaching second coxae; prementum almost 1.4 times as long as wide; anterior margin convex and slightly crenulated, with 5 or 6 premental setae (2+1 or 3), the inner ones usually shorter than the others or the same size than the others; lateral margin with usually 8 spiniform setae ( Fig. 9 ). Labial palp with four setae; outer half of distal margin with three very small teeth, inner half with three teeth and a curved end hook; movable hook slender and sharp; inner margin of palp slightly crenulated ( Fig. 10 ). Mandibular formula L 1+2 3+4 5 0 a b, R 1+2 3 4 5 y a ( Figs. 11 a,b).

Thorax. Wing pads nearly parallel, the external reaching middle of S4. Legs pale; femora with a row of spiniform setae on the dorsal and lateral surface; tibiae with sparse, long and delicate setae on the external surfaces, apical ends with a delicate group of setae on the internal surface; tibiae II and III with two row of spiniform setae on the internal surface; tarsi with two rows of setae on the ventral surface.

Abdomen. Cylindrical. Light brown. Dorsal spines on the tergite surface S 4–10 in female and 5–10 in male. A row of lateral spines on S2–10. Male gonapophyses sharply pointed and divergent with a row of 5 spines, surpassing mid-length of S10 ( Fig. 12 ). Female gonapophyses exceeding posterior margin of sternite 10, lateral valvae sharply pointed with a ventral row of 5 robust spiniform setae and 4 lateral spines ( Fig. 13 ). Male cerci as in Figure 12 , female cerci as in Figure 13 . Caudal lamellae lanceolate, with width/length ratio 0.13 ( Fig. 14 ). Dorsal margin of lateral caudal lamella with about 40 setae; ventral margin with about 15 setae. Tracheation as in Figure 14 .

Measurements. (mm). Total length (without caudal lamella) (N=3): 10.23 [9.83–10.96]. Head: maximum length: 1.44 [1.42–1.48]; maximum width: 2.16 [2.10–2.27]. Prementum: maximum length: 2.16 [2.10–2.27]; maximum width: 1.53 [1.48–1.59]. Thorax: femur I: 1.54 [1.49–1.57]; femur II: 1.86 [1.79–1.99]; femur III: 2.47 [2.38–2.52]; tibia I: 1.78 [1.75–1.80]; tibia II: 2.14 [2.09–2.18]; inner wing pads maximum length: 3.75 [3.73– 3.78]; outer wing pads maximum length: 3.49 [3.29–3.68]. Abdomen: total length: 6.05 [5.64–6.77]; S9 length: 0.35 [0.29–0.39]; S10 length: 0.37 [0.34–0.41]; cerci length: male (N=1): 0.14, female (N=2): 0.11; female gonapophyses length (N=2): 0.80; male gonapophyses length (N=1): 0.27. Lateral caudal lamella (N=1): maximum length: 6.36.

Specimens examined. 3 exuviae (1 male and 2 females reared). BRAZIL: Espírito Santo State, Estação Biológica de Santa Lúcia, Lagoa Molino, 24.vii.2009, leg. D. Anjos-Santos, C. Carriço, J.M. Costa & T. C. Santos (1 3) [emerged in laboratory: 02.viii.2009]. Rio de Janeiro State, Rio de Janeiro, São Cristóvão, Horto FAHUPE, Col.15, Estação 3, nº15, 20.xi.1985, leg. J. R. Pujol-Luz (1 Ƥ) [emerged in laboratory: 13.i.1986]; 27.i.1986, leg. J.R. Pujol-Luz (1 Ƥ) [emerged in laboratory: 17.ii.1986].

Figures

FIGURE 8 – 14. Acanthagrion lancea, details of larval morphology: (8) head, dorsal view; (9) prementum, dorsal view; (10) labial palp, dorsal view; (11) mandible, inner view: (a) right mandible, (b) left mandible; (12) male gonapophyses and cerci, lateral view; (13) female gonapophyses and cerci, lateral view; (14) lateral caudal lamellae, lateral view.