Erythrodiplax abjecta (Rambur)

Palacino-Rodríguez, Fredy, Rache-Rodríguez, Leonardo & Castillo, Daniel R., 2019, Description of the last stadium larva of Erythrodiplax abjecta (Anisoptera: Libellulidae) from the eastern Colombian Andes, Zootaxa 4545 (1), pp. 139-145 : 140-142

Larva of Erythrodiplax abjecta (Rambur)

Figures 1 a–f.

Material. Eleven F–0 larvae (1 ♂ + 10 ♀♀ reared). Colombia, Cundinamarca department, road connecting Guasca and Gachetá municipalities, Sueva river 04° 48’ N, 73°43’ W, elevation 2,282 m, 20–II to 18–VIII–2017, D. Palacino, A. Penagos & F. Palacino–Rodríguez leg. Six exuviae (1 ♂ + 5 ♀♀ collected). Same data, but Sesquilé municipality, Tierra Negra township 04° 59’ 34.6” N, 73°46’ 45.1” W, elevation 2,898 m, 09–XII–2017 (emerged at Sesquilé, from 10 to 26–XII–2017) , L. Rache–Rodríguez, H. Prieto, D. Palacino & F. Palacino–Rodríguez leg.

Description. Larva ( Fig. 1a ) pale brown. Legs and S5–9 very setose. Abdomen short and ovate, with lateral spines on S8–9. No middorsal hooks on abdomen.

Head. Trapezoidal, 1.58 times as wide as long with large compound eyes. Antennae, 1.65. Mandibular formula: L 1 2 3 4 0 a b / R 1 2 3 4 y a b d. Articulation of pre-postmentum between first and second coxae. Prementum–palp articulation with 4 spines (premental spines); prementum with 11 setae on each side of the midline. Labial palp with 11 crenulations and 7 setae, external margin of crenulations finely serrated, with one stout, internal setae on each crenulation. Thorax. Brown, 1.13 times as wide as long. Wing pads reaching S6 and S7. Abdomen. Pale brown; middorsal hooks, protuberances or spines absent; lateral margins of S5–9 with abundant amount of setae, lateral spines on S8 and S9 present, those on S8, 0.15 length and 0.2 length in S9. Caudal appendages sharply pointed and smoothly curved in the tip, epiproct wider at base, apex acute. Ratio relative to paraprocts: epiproct 0.73, cerci 0.93.

Measurements: Total body length (excluding paraprocts): 12.9. Head maximum width: 4.5. Head maximum length: 2.55. Antennae: 1.65. Prementum maximum width: 3.55 Prementum maximum length: 3.35. Labial palp maximum width: 1.85. Labial palp maximum length: 2.1. Movable hook length: 0.6. Thorax maximum width: 3.7. Thorax maximum length 3.25. FW pad length: 5.2. HW pad length: 4.85. Femur III length: 4.25. Tibia III length: 4. Abdomen maximum width: 4.9. Abdomen maximum length: 7.1. S10 length: 0.2. Cercus length: 0.75. Paraproct length: 0.7. Epiproct length: 0.95

Variation in larvae and exuviae. Some specimens body dark brown. Most specimens with spines in S8 and S9, however, three individuals of them without lateral spine in S8.

Head. Three prementum-palp articulation spines in four individuals; ten or twelve setae on prementum in some individuals. Labial palp with six setae in few cases and 8 in one individual. Thorax. Some individuals dark brown; two individuals <1 times as wide as long. Most individuals wingpads reach S6, only one reach S4. Abdomen. Lateral margins of S5–S9 with little amount of setae in some individuals. Lateral spines on S8 absent on three individuals, length of S8 and S9 up to 0.2 and 0.3 respectively. Ratio relative to paraprocts: epiproct 0.70–0.92, cerci 0.8–1.3.

Larvae measurements: Range of measurement in brackets; average; standard deviation in parentheses; N=12. Total body length (excluding paraprocts): [11.10–14.60] (12.93±1.12). Head maximum width: [3.85–4.50] (4.22±0.19). Head maximum length: [2.40–3.00] (2.62±0.18). Antennae: [1.60–1.85] (1.71±0.08). Prementum maximum width: [3.20–3.65] (3.50±0.13). Prementum maximum length: [3–3.8] (3.42±0.20). Labial palp maximum width: [1.45–2.05] (1.88±0.16). Labial palp maximum length: [1.70–2.30] (2±0.15). Movable hook length: [0.45–0.65] (0.57±0.07). Thorax maximum width: [3.15–4.25] (3.75±0.28). Thorax maximum length [2.55–3.9] (3.17±0.34). FW pad length: [4.8–5.8] (5.25±0.30). HW pad length: [4.50–5.00] (4.80±0.17). Femur III length: [3.6–4.75] (4.14±0.34). Tibia III length: [4.00–4.95] (4.57±0.33). Abdomen maximum width: [4.00–5.15] (4.74±0.31). Abdomen maximum length: [6.55–8.25] (7.23±0.53). S10 length: [0.15–0.35] (0.21±0.06). Cercus length: [0.50–0.80] (0.71±0.08). Paraproct length: [0.60–0.85] (0.70±0.06). Epiproct length: [0.70–1.00] (0.87±0.09).

Exuviae measurements (in mm): Range of measurement in brackets; average; standard deviation in parentheses; N= 6. Total body length (excluding paraprocts): [11.85–15.45] (13.52±1.37). Head maximum width: [3.75–4.75] (4.23±0.39). Head maximum length: [2.25–2.85] (2.43±0.25). Antennae: [1.5–1.9] (1.75±0.17). Prementum maximum width: [3.05–3.75] (3.39±0.31). Prementum maximum length: [2.9–4.25] (3.42±0.50). Labial palp maximum width: [1.45–2.10] (1.80±0.22). Labial palp maximum length: [1.75–2.25] (2.05±0.17). Movable hook length: [0.55–0.7] (0.63±0.06). Thorax maximum width: [3.25–4.60] (3.74±0.53). Thorax maximum length [1.95–4.65] (3.21±0.92). FW pad length: [2.80–5.2] (3.95±1.21). HW pad length: [2.45–5.05] (3.63±1.27). Femur III length: [3.45–4.5] (3.85±0.43). Tibia III length: [4.05–4.8] (4.50±0.29). Abdomen maximum width: [4.25–5.6] (4.85±0.50). Abdomen maximum length: [7–9.25] (7.87±0.85). S10 length: [0.2–0.25] (0.22±0.02). Cercus length: [0.50–0.70] (0.60±0.08). Paraproct length: [0.60–0.75] (0.65±0.06). Epiproct length: [0.80–0.9] (0.85±0.03)

Diagnosis of the last stadium larva of E. abjecta . Erythrodiplax abjecta differs from most of the other known larvae of Erythrodiplax by the presence of 3–4 spines in the prementum–palp articulation, a character shared with E. basifusca ; E. berenice (Drury) ; E. bromeliicola ; E. connata ; E. corallina , E. laselva ; E. minuscula (Rambur) ; E. naeva (Hagen) ; E. nigricans (Rambur) ; E. pallida (Needham) and E. umbrata (Linnaeus) . From these species, only E. basifusca , E. bromeliicola , E. connata and E. minuscula share with E. abjecta the presence of one seta on each crenulation of labial palp, but E. connata is easily separated by the absence of lateral spines on abdomen. Erythrodiplax abjecta differs from the latter group of species by having the smallest prementum max. width/max. ratio Ẽ 1.05.

Figures

FIGURE 1. Morphology of last instar larva of Erythrodiplax abjecta; a. dorsal view of the last instar larva; b. right mandible (inner view); c. left mandible (inner view); d. prementum; e. labial palp; f. apex of abdomen. Illustrations: P. Camacho.