Rhionaeschna caligo, Bota-Sierra, 2014

Arango-Quintero, Sebastian, Sánchez, Isabel Cardona, González, Wilmar Zapata & Bota-Sierra, Cornelio A., 2025, Rhionaeschna caligo revisited: female and larval descriptions, new geographical records and natural history notes (Odonata: Aeshnidae), Zootaxa 5659 (1), pp. 104-116 : 107-114

Last instar larva description

Exuvia light brown, larva dark brown both with nearly uniform color pattern ( Figs. 3a–b ).

Material. Eleven exuviae (4 ♀♀, 7 ♂♂), 1 F–0 larva (♂). Colombia. Antioquia: Belmira municipality, Páramo el Morro, La Ciénaga wetland , 6.677333° N, 75.671417° W, elevation 3,233 m a.s.l. 1–28.iv.2024, Leg: S. Arango, C. Bota, and S. Serna. Deposited at CEUA .

Head ( Fig. 4a ). Broader than long, with small hairs around the cephalic lobes and antennae, cephalic lobes granular and with rows of small hairs, concave occipital margin, antenna with 7 antennomeres ( Fig. 4b ) with the 3rd antennomere more elongated and with relative sizes as follows 0.3, 0.4, 1.0, 0.4, 0.5, 0.5, 0.6. Labrum granular ( Fig. 4a ). Mandibles ( Fig. 4c ) with a row of bristles on the inner edge just below the molars, external basal area with numerous small spiny setae, formula: R 1 2 3 4 and a a” b b” d- / L 1 2 3 4 0 a (m) b d-. Maxilla: galeolacinia with seven long, curved teeth, a long, bushy row of setae on the outer margin, another row of short, stiff spines on the inner margin, and a curved palp ending in a robust, blunt spine. Labium: with a smooth appearance, without a row of setae or hairs, except the internal side of prementum with a granular appearance due to the insertion of tiny setae ( Figs. 4d , 5a ), prementum 0.25 times longer than its widest part ( Figs. 4d , 5a ), lateral margins divergent widening towards the apex, distal margin of ligula rounded, with a median cleft and a row of 35–40 tiny piliform setae ( Fig. 4d ), setulae on the external area of the palp base ( Fig. 4d ), apical lobe of the palp quadrately truncated, with inner apex slightly pointed, mobile hook as long as the palp, smooth and pointed ( Fig. 5b ). Articulation between prementum and postmentum close to reaching the beginning of the metacoxae ( Fig. 5a ),

Thorax. Pronotum granular, with multiple small setose projections and with a sinuous posterior margin, prothoracic processes convex as shown in the photo ( Fig. 5c ), parallel wing pads, reaching S4. Legs yellowish brown, with abundant spiniform setae. Femora with alternating light and dark bands ( Figs. 3a–b ). Ventral surface of all tarsi with scale like tridentate setae. Tarsal claws simple.

Abdomen. Broadest part on S6 ( Fig. 3b ), lateral margins with small spiniform setae, lateral margins of segments S6–S9 ending in robust spines, those of S9 being the most robust and those of S6 the smallest ( Fig. 5d ). Male gonapophysis indiscernible, female gonapophysis as long as the length of S9 ( Fig. 5e ). Male epiproct with dorsobasal tubercle on dorsobasal 0.47 of the total length of the epiproct ( Fig. 5f ), which ends in two sharp points separated by a U-shaped cleft ( Fig. 5f ), female epiproct without dorsobasal tubercle. Paraprocts with parallel tips, sharp and caudally pointed ( Fig. 5f ), with a row of five spiniform projections on the external margin. Cerci rather cylindrical and rounded, smooth without setae, with very sharp reddish tips, slightly convergent ( Fig. 5f ).

Measurements (mm) (Mean. N and range in square brackets): Total length (including appendages): ♂ 45.3 [N=6; 40–47]; ♀ 46 [N=3; 43–49]; abdomen (ventral): ♂ 26.4 [N=7; 24–27.1]; ♀ 27.3 [N=3; 26–29]; maximum width of head: ♂ 8.1 [N=7; 7–8.5]; ♀ 7.5 [N=3; 7–8]; hind femur (dorsal): ♂ 8.2 [N=8; 7.2–9.5]; ♀ 8.7 [N=3; 8–10]. Lateral spines on abdomen: S6: ♂ 0.4 [N=8; 0.4–0.5]; ♀ 0.4 [N=3; 0.3–0.5]; S7: ♂ 1.1 [N=8; 1–1.2]; ♀ 1 [N=3; 1.0]; S8: ♂ 1.2 [N=8; 1.1–1.4]; ♀ 1.2 [N=3; 1–1.3]; S9: ♂ 1.6 [N=8; 1.5–1.8]; ♀ 1.4 [N=3; 1.3–1.5]. Caudal appendages (external margin): epiproct: ♂ 3.5 [N=6; 3.2–3.7]; ♀ 3.5 [N=2; 3.2–3.8]; cerci: ♂ 2.8 [N=6; 2.6–3.1]; ♀ 2.8 [N=2; 2.4–3.1]; paraprocts: ♂ 4.9 [N=6; 4.3–5.0]; ♀ 4.8 [N=3; 4.4–5.0].

Diagnosis

Few Rhionaeschna larvae have been described. In the R. punctata group where R. caligo belongs ( von Ellenrieder 2003), only three of the eight species had their larvae described previous to this work (De Marmels 2001; Santos 1966): R. demarmelsi von Ellenrieder, 2003 , R. punctata ( Martin, 1908) , and R. condor (De Marmels, 2001) . Here we compare the fourth larvae in this group with the previously described ones. We also compared with R. marchali ( Rambur, 1842) larvae ( Limongi 1983) since it is the only congener that shares habitat.

The larva of R. caligo is very similar to the other larvae described in the R. punctata group, which makes it a bit difficult to differentiate, unfortunately we could not examine material of the other species to compare, so this diagnosis is based on literature (De Marmels 2001; Limongi 1983), the description of the larva of R. punctata ( Santos 1966) lacks some important details to make a proper comparison.

[Characters for R. demarmelsi , R. condor and R. marchali in brackets]: Prementum-postmentum articulation reaching almost to the metacoxae ( Fig. 5a ) [reaching half length of the metacoxae in R. demarmelsi , just behind the mesocoxae in R. condor , unknown in R. punctata and up to half length of the mesocoxae in R. marchali ]; abdomen uniformly dark brown with no noticeable pattern ( Figs. 3a–b , 5d ) [abdomen with color pattern with pale and dark areas on margins R. demarmelsi , abdomen with pale spots on edges of segments S6–9 R. condor , abdomen gray with two light parallel dorsal stripes, S3–9 with complex patterns of lateral spots R. punctata ]; wing thecae barely reaching anterior edge of S4 ( Figs. 3a–b ) [wing thecae reaching as far as S 5 in R. demarmelsi , R. condor and R. punctata , wing thecae exceeding posterior margin of S4 R. marchali ]; lateral spines on abdominal segments S6–9 ( Fig. 5d ) [shared with R. demarmelsi , R. condor and R. punctata , R. marchali without spine on S6].

Adult female description

Large dragonflies, with a combination of green and blue color on a brown background ( Fig. 6 ). Body covered with setae as follows: black setae on head; golden, abundant and long seta on thorax; few golden setae on ventral abdominal area ( Figs. 6–8 ).

Material (5 ♀♀): 2 ♀♀, Antioquia: Municipality of Belmira: Páramo El Morro : La Ciénaga : N 6.677339° W -75.671405 3233 m, 24.i.2024, Leg: S. Serna, S. Arango & C. Bota . 1 ♀, same data but: Leg: W. Zapata, I. Cardona & C. Bota . 1 ♀; Leg: A. Hoyos, C. Zapata & C. Bota ; 1 ♀ Leg: K. Alvarez, M.I. Pérez, F. García & C. Bota .

Head. Labrum yellow. Clypeus and antefrons yellowish green on the medial portion, becoming yellow towards the lateral margins ( Fig. 7b–c ), with a narrow and uniform brown stripe on frontoclypeal groove ( Fig. 7b ). Postfrons with black T-shaped spot, the stem of the T-shaped spot is thinner than the vertex width ( Figs. 7a – 8a ), the transversal arms of the T-spot almost as wide as the stem, at the sides of the stem two yellow spots followed by two bluish-gray spots ( Figs. 7a – 8a ). Vertex black with two yellow spots on the anterior margin ( Figs. 7a, c , 8a ). Occipital triangle yellow ( Figs. 7a, c , 8a ).

Thorax: Pronotum brown. Pterothorax: mesepisternum brown with two small yellow-green spots, the anterior one elongated longitudinally parallel to the pterothoracic crest, second an ovoid spot transversal to pterothoracic crest on the posterior fourth ( Fig. 8a ). Antealar crest brown, metepistenum with a thick yellow-green band with an indentation towards the anterior margin, interrupted near the mesepimeron (divided in two spots), the width of the band is 50% of the sclerite ( Fig. 8a ). Metepimeron with a yellow-green band with two indentations, one towards the anterior margin and one on the posterior margin, in the shape of an inverted S ( Fig. 8a ).

Legs: black except for the trochanter, coxa and the basal 80% of the femur, which are light brown. Spines on the outer margin of the metafemora: 30. Spines on the outer margin of the metatibia 14.

Wings: Hyaline, tinged yellow towards the base. Ax: right FW: 19, left FW: 21; right HW: 13, left HW: 14; Px: right FW: 15, left FW: 17; right HW: 16, left HW: 17; triangle cells right FW: 4, left FW: 5; HWs: 4; supratriangle crossveins FWs: 4; HWs: 3; subtriangle cells FWs: 2; HWs: 2; cu-A space crossings FWs: 6; HWs: 4; bridge crossveins FWs: 4; right HW: 3, left HW: 4; rows of anal loop cells FW: 3, HW: 3; cell rows under distal end of Pt between RP 2 and IRP 2 FW: 4; HW: 4; anal loop cells: 11.

Abdomen: brown with light colored spots: greenish-blue lateroposterior spot on S1 ( Figs. 6 , 8a ); S2 with greenish-blue ventrolateral band across the entire segment, two lines cross the segment like thin arches dorsally, one anterior to the transverse carina, interrupted medially, the other one is thicker on the posterior carina, a medial line connects the anterior and posterior carinas ( Figs. 6 , 8a ); S3 greenish-blue lateral band reaching the transverse carina, with a line that extends dorsally anterior to the posterior carina, briefly interrupted by the mediodorsal carina; S4–7 with two green spots, anterior bifurcating dorsally in two arches, posterior on the transverse carina extending dorsally and interrupted by the mediodorsal carina ( Fig. 6 ); S8 lateral greenish band below the lateral carina ( Fig. 8d ), posterodorsal spot present. S7 sternite with concave external margin, anterior part with a width greater than 40% of the sclerite ( Fig. 8c ). Cerci: longer than S10 + S9 length ( Fig. 6 ), with carina on the outer margin and a medial longitudinal carina running the entire cercus, black hairs on the anterior margin, maximum width at 50%, with pointed tips ( Fig. 8b ).

Measurements (mm): Total length 69; abdomen length 51; cercus length 5; FW length 47.

Variation

The coloration of S1–3 varies from green to blue. Wing morphological characters: Triangle cells: right FW: 4–5; left FW: 3–5; HWs: 4. Rows of cells in anal loop: 3. Anal loop cells: right HW: 12–15; left HW: 11–14. Cell rows under distal end of Pt between RP2 and IRP2: FW: 2–3; HW: 3–4. Bridge crossveins: right FW: 3–4; left FW: 4; HW: 3–4. Cu–A space crossveins: right FW: 4–6; left FW: 5–6; HW: 3–4. Subtriangle cells: FW: 2; right HW: 2–3; left HW: 2. Supratriangle crossveins: right FW: 4; left FW: 3–4; HW: 2–3. Ax: right FW: 18–21; left FW: 17–28; HW: 12–13. Px: FW: 13–14; right HW: 15–17. Leg morphological characters: spines on external margin of metafemur: 27–29. Spines on external margin of metatibia: 12–15.

Measurements (mm): Cercus length: 5. Abdomen length: 47–51. Total length: 65–69. FW length: 43–48.

Taxonomic key

Couplet 6 of Key F-3 for females of the Rhionaeschna punctata group in von Ellenrieder (2003) can be modified as follows to accommodate this species:

6. PD spots absent in S8–10; (fig. 192b); maximum width of cercus at medial 30%; larger species (cercus 6.5 mm, total length 68–72.5 mm); Bolivia to Colombia (fig. 458)........................................... R. joannisi ( Martin, 1897)

6’. PD spots present in segment S8 or PD spots present in segments S8–10, smaller species (cercus 5mm, 58.3–69).......... 7

7. PD spots present in S8, S9–10 brown; outer margin of S7 concave ( Fig. 8c ); maximum width of cercus at distal 50% ( Fig. 8b ); North of Central and Occidental Cordilleras in Colombia................................................ R. caligo

7’. PD spots present in segments S8–10; outer margin of S7 linear; maximum width of cercus at distal 30%; Merida Cordillera in Venezuela................................................................................ R. demarmelsi

Figures

FIGURE 3. Rhionaeschna caligo, male larvae habitus: a, lateral view. b, dorsal view.

FIGURE 4. Rhionaeschna caligo, head morphological details: a, head, dorsal view. b, right antenna. c, mandibles: a’ and b’, ventrointernal view of right and left mandibles, respectively; c’ and d’, dorsoexternal view of right and left mandibles, respectively. d, Prementum, dorsal view. X: maximum width; Y: maximum length.

FIGURE 5. Rhionaeschna caligo, body morphological details: a, prementum, ventral view. b, right labial palp, dorsal view. c, right prothoracic apophyses, dorsal view. d, S6–10, dorsal view. e, S9 sternite and gonapophyses (female exuvia). f, caudal appendages, dorsal view of epiproct, cerci, and paraprocts. r. p. p–p: resting place for prementum–postmentum articulation.

FIGURE 6. Rhionaeschna caligo male (left) and female (right) habitus. Photograph: Sebastian Serna.

FIGURE 7. Rhionaeschna caligo female head: a, dorsal view. b, lateral view. c, front view.

FIGURE 8. Rhionaeschna caligo female: a, thorax; b, cerci dorsal view; c, S7 sclerite; d, S8–10 lateral view.