Thecagaster charpentieri ( Kolenati, 1846 )

Thecagaster charpentieri ( Kolenati, 1846) View in CoL

Cordulegaster insignis nobilis Morton, 1916 View in CoL

Cordulegaster insignis lagodechica Bartenev, 1930 View in CoL

Cordulegaster nachitschevanica Skvortsov & Snegovaya, 2015 View in CoL

Cordulegaster plagionyx Skvortsov & Snegovaya, 2015 View in CoL

General: The exuviae of T. charpentieri View in CoL exhibit the characteristic morphological features of Cordulegastridae View in CoL larvae ( Fig. 5 View FIGURE 5 ). The pigmentation of the entire body is uniformly brown with no distinct darker colour patterns. The cuticle is covered by a layer of fine and sparsely distributed setae. These setae are distributed on the abdominal sternites and tergites as well as on the upper side of the thorax. Under the particle-covered surface there are faint darker colour patterns. In addition, longer setae and hairs are conspicuously distributed on the posterior edge of the thorax as well as on parts of the legs, the tergites, the anterior edges of the sternites and the appendages.

Head: In dorsal view, the head almost rectangular, but in the posterior region the lateral margins are gently rounded-converging ( Fig. 6A View FIGURE 6 ), with a maximal width between 7.5–7.8 mm in males (N=2) and 8.5 mm in female (N=1), clypeus brown coloured, anterior margin of frons adorned with a series of short setae, compound eyes notably large, contributing to the formation of antero-lateral angles, while the internal regions of eyes dark brown, antennae consists of 7 segments.

The labium ( Figs. 6B–6C, 6E View FIGURE 6 ) extend ventrally beyond the middle coxae in the resting position. Prementum length-to-width ratio = 1.0. Cranial edge of ligula is characterized by a densely packed row of very short setae, and medially with two slightly dissimilar humped protuberances ( Fig. 6D View FIGURE 6 ). Along the lateral edges of the prementum, exists a series of more or less short, uniformly setae. The mesial margins of the palpal lobes are characterized by conspicuously irregular, pointed teeth typical of Cordulegastridae ( Figs. 6B–6C, 6E View FIGURE 6 ), the tips of all teeth being strongly sclerotized, as evidenced by their strong brown coloration. Moveable hooks are described as long and robust, with a dark brown tip. From dorsal view the prementum features 5 long and 2–4 short setae on each side ( Fig. 6E View FIGURE 6 ). The palpal lobes bear 5–6 palpal setae, and their outer margins are edged with two rows of dense setae ( Fig. 6E View FIGURE 6 ).

Thorax: The pronotum is broad, reaching approximately to the vertical midline of the eyes, with a width ratio between the pronotum and head of approximately 1:1.2. On the lateral edges there are strong, thorn-like bristles pointing upwards. The wing sheaths of the forewings extend to the 4th abdominal segment. The tarsi are 3- segmented with a two-part claw, tarsal segments are covered with dense bristles, at the proximal ends, especially on their ventral area. Strong spines and long flexible bristles are present on the dorsal surfaces of the segments 2 and 3 of the hind tarsi ( Fig. 7D View FIGURE 7 ).

Abdomen: all sternites of S1–10 are densely covered with marginal, hair-like spines. Short bristles are loosely distributed over the entire surface of the abdomen, both on the tergites and on the sternites. The tergites have long, hairy pubescence along their margins, with shorter, finer pubescence on the surfaces of the tergites. The female gonapophyses (ovipositor) extend to the caudal margins of segments S9 ( Figs. 7C, 7G View FIGURE 7 ). In males, the projection of the epiproct has slightly conical lateral margins ( Fig. 7E View FIGURE 7 ). The length of the male projection is about a third as long as the entire epiproct, rear edge slightly concave indented ( Fig. 7E View FIGURE 7 ). The epiproct of the female forms a spiky caudal tapered tip on its half ( Fig. 7F View FIGURE 7 ). The cerci of the male exuviae ( Fig. 7E View FIGURE 7 ) are stouter in comparison to the female exuviae ( Fig. 7F View FIGURE 7 ), the cerci reach one third of the length of the entire anal pyramid in both sexes ( Figs. 7E–7F View FIGURE 7 ). In both sexes, the tips of the paraprocts and epiprocts point slightly downwards in the lateral view ( Fig. 7G View FIGURE 7 ), mesial margins of the paraprocts seen ventrally with a dense bristle crest and with a cuticularly reinforced groin. The distal edges of the paraprocts have short, strong bristles. Lateral and dorsal spines are absent in both sexes ( Figs. 7A, 7C View FIGURE 7 ).

Measurements: total length 37.5–40.5 mm males N=2, 41.7 mm female N=1 (approximate value); head width 7.5–7.8 mm males N=2, 8.5 mm female N=1 (approximate value); length of mentum 6.0– 6.3 mm males N=2, 7.0 mm female N=1; basal width and distal width of mentum: 2.2–2.3 / 5.9–6.2 mm males N=2, 2.5/ 7.2 mm female N=1; length of wing case of hindwing: 8.3–8.7 mm males N=3, 10.2 mm female N=1; length femur foreleg (without trochanter) 4.1–5.2 mm males N=2, 5.4 mm female N=1; length tibia foreleg 5.5 mm males N=2, 6.1 mm female N=1; length tarsus foreleg 2.7–2.9 mm males N=2; length tarsal segments (example male N=1) T1 0.8, T2 0.7, T3 1.3 mm, length abdomen: 25.7–27.4 mm males N=3, 23.0 mm females N=1; abdomen maximum width, 7.4–7.9 mm males N=3, 8.0 mm female N=1; lengths cerci 0.98–1.08 mm males (N=3), 1.2 mm female (N=1); cerci basal width 0.41–0.46 mm males (N=3), 0.5 mm females (N=1); lengths paraproct (inner margin in ventral view) 2.6–2.78 mm males (N=3), 3 mm female (N=1); lengths epiproct (in dorsal view): 2.3–2.9 mm males (N=3), 3.3 mm female (N=1); lengths male projection: 0.6–0.7 mm (N=3), female gynapophyses: 2.0 mm (N=1); length of antennae 3.2 mm (example male N=1).

Additional characteristics of the larvae in the F-6 stage.

The larvae are 6.0 and 6.2 mm long, the entire body is densely covered with bristles, faint pigmentation is visible on the abdomen ( Fig. 8A View FIGURE 8 ), head widths 1.4 mm, antennae 6-segmented, shape of the mentum corresponds to that of the F-0-larvae (exuviae) ( Figs. 8B, 8D View FIGURE 8 ), in contrast to the F-0-larvae, the small larvae have 2 prominently developed protuberances on the cranial margin of the ligula ( Fig. 8C View FIGURE 8 ). The edges of the protuberances are serrated. Inside of the mentum there are 4 strong bristles on each side, distal margins of the palps with 12 bristles ( Fig. 8B View FIGURE 8 ), paraprocts and the epiproct are comparable in shape to those of the F-0-larva (exuviae), the cerci are missing ( Fig. 8A View FIGURE 8 ). The sex of these specimens cannot be determined morphologically.