Megaloprepus brevistigma Selys, 1860

Feindt, Wiebke & Hadrys, Heike, 2022, The damselfly genus Megaloprepus (Odonata: Pseudostigmatidae): Revalidation and delimitation of species-level taxa including the description of one new species, Zootaxa 5115 (4), pp. 487-510 : 496-497

Megaloprepus brevistigma Selys, 1860

( Figures 4 , 6 , 7 , 8 )

Megaloprepus Race brevistigma Selys 1860: 13–14 (description and diagnostic characters). Selys 1886: 7–8 (refusal of species status); Ris 1916: 65–66, 189 (description of male and female, diagnostic characters); Schmidt 1942: 229 (reconsideration of origin of M. brevistigma ); Heckman 2008: 201–203, Fig. 3.1 .210 (key to the genus); Fincke et al. 2018 (considering subspecies status).

Specimens examined. (9 specimens: 9 syntypes).

Syntypes: Colombia, Bogota: 9♀♀ (RBINS: E. Selys Longchamps) .

Other material examined (36 specimens): Colombia: 1♂ (RBINS: E. Selys Longchamps ) ; 1♂, leg. J. Müller (RBINS: R.M.H.N.B. 16.364); 1♂, leg. Don Dr. P. Elsen (RBINS: IG: 28.483); 1♂, leg. Throt (RBINS: Reg. Mus. His. Nat. Belg. IG: 11.128) ; 10♂♂ 10♀♀, 1934, leg. F. Ovalle (AMNH: Ac 33501); Bogota : 5♂♂ (RBINS: E. Selys Longchamps); Boyacá , Santa Maria: 1♂, N 5°14’16.8” W 73°16’15.348”, 1050 m, iii. 2015, leg. D. García (ANDES-E: 18803).— Ecuador, Macas, Rio Upano , Morona-Santiago : 1♂, leg. F.M. Brown (AMNH); Puyo Oriente, Amazonía : 1♂, app. S 2°11’14.41” W 78°5’23.71”, v. 1938, leg. F.M. Brown (AMNH).— Peru: 1♂ (RBINS: E. Selys Longchamps); La Merced, La Salud-Vía Chanchamayo : 1♀, (AMNH); Junín , Río Oxabamba, Pampa Hermosa Lodge : 2♂♂, S 10°59’ W 75°25’, 1900m, xii. 2008, leg. T.D. Donnelly (FSCA).

Notes. The first introduction of M. brevistigma by Selys was based on females only and no male has been described so far. The mature male described here was chosen from Selys’ original collection—a specimen that was assigned by Selys himself (identifiable by his handwriting) to the ‘ race brevistigma ’ and which originate from Bogota in Colombia. This specimen unfortunately did not have a collection date. For the AMNH, Dr. Felipe Ovalle collected most specimens in a single expedition in 1934. The complete collection included about 30,000 specimens (Ac 33501) and no exact locality determination for most of these specimens was possible.

Mature male. Head. Labium yellow becoming dark brown at anterior margin. Mandible base yellow, turning black towards anterior margin. Gena yellow. Labrum, anteclypeus, postclypeus and frons shining black. Antennae black with a light ring around their base. Vertex and rear of head black.

Thorax ( Fig. 4 ). Prothorax black. Anterior lobe contains additional round to oval yellow markings at both ends and centrally an oval yellow mark. Posterior lobe with very small yellow spots at the most lateral surfaces (almost unapparent). Anterior and posterior lobes smoothly rounded. Middle lobe convex and shortened at the center. Propleuron slightly hairy, slightly convex with C-shaped, dorsally directed green area nearly covering half, distal margins with broad dark-yellow coloration (as in Fig. 4a, b ). Pterothorax black with narrow, linear, yellow antehumeral stripe beginning at approximately 25% of length; ends of mesostigmal plates somewhat round pointed tips with small dark yellow spots; membranous area between posterior lobe of prothorax and mesostigmal plates black with a yellow mark; yellow stripe covering metepisternum also includes lower ventral part of mesepimeron and metastigma at its lowest border, decreases in width towards wing bases between FW and HW; entire metepimerum yellow with a smaller green stripe. Venter yellow with pruinescence continuing to coxae. Coxae yellow with brown/black markings. Remaining internal and dorsal side of legs black, inner surface of femora yellow, external side of tibiae yellow. Tarsi, spines and claws entirely black. Two rows of spines on femora and tibiae, centrally directed.

Wings ( Fig. 6 ). Wings stalked, elongated and slender compared to the other Megaloprepus species (width/length ratio FW 0.20, HW 0.20), wingtips shallow rounded, without sexual dimorphism in coloration, mostly hyaline except for a metallic dark blue band crossing wing at most distal quarter of each wing, pseudostigma and two additional white spots at wingtips. Metallic dark blue band narrow (width at the costa FW 10.5, HW 10.3; ratio width of blue band/wing length: FW 0.16, HW 0.16), less gleaming. Two additional shining white, nearly round wing spots at wingtips: one at upper margin between pseudostigma and blue band, second at lower wing margin, distal from blue band but proximal of IR 1, here secondary venation also partly white. Pseudostigma dark blue, small, almost rectangular, covers 2 cells (please compare Ris 1916). Area basal of CuA broad but smaller than in M. caerulatus ; CuA forks five times, secondary branching less common. MP bifurcates 4 cells apart from wing margin.

Abdomen. Abdomen slender and elongate, black. S1–5 with a variety of green yellow markings as follows: in S1 and S2 entire lateral terga covered; in S3 and S4 ventral parts of tergites are colored, entire length of S3 and approximately 75–80% of both, S4 and S5.

Genital ligula ( Fig. 7 ). Second segment with very prominent inner fold with sclerotized hair-like structures on both sides. Lateral lamina of distal s2 starts at lateral ends of inner fold, frames widely rounded around distal half of s2, and forms apical lobe. Filamentous whip-like distal segment contains ventrally directed process close to base. Process narrow, not much wider than distal segment, appears folded, with lateral emargination.

Caudal appendages ( Fig. 8 ). Appendages brown, small. Cercus biramous, both ends acute (lateral view), slightly hairy dorsal branch directed dorso-distal, inner parallel branches point aligned ventrally and hidden between paraproct bases. Paraproct longer than cercus, with few hairs, triangular in side view with a steep acuminate dark black-brown tip directed dorso-distal. Paraprocts in lateral view quadrangular with A angulated convex and B slightly concave (almost straight), D = 69% of L – L’ length.

Measurements. AL 82.4, FWL 67.0, HWL 65.8.

Variation in the other material examined. Membranous area between posterior lobe of prothorax and mesostigmal plates sometimes entirely black. In 95% of the other material examined the metallic blue band proceeds proximal between C and RA for 4-11 cells, sometimes reaching the same length as the blue band itself. MP variable among specimens: in four out of 10 male hind wings MP not bifurcated. The number of cells between bifurcation and wing margin are 4–9 in FW and 0–11 in HW. Pseudostigma is never longer than 3.28 (FW) and 3.02 (HW) (please compare Ris 1916). Paraprocts always quadrangular, but tip sometimes more sharp (N = 10).

Measurements. ♂ AL 75.9–106.1, mean: 90.7.1±9.4, FWL 63.0–94.2, mean: 77.3±9.0 (N = 10). ♀ AL 71.2– 94.7, mean: 86.4±7.4, FWL 66.9–79.8, mean: 74.4±5.3 (N = 11). Wings: ♂ width/length ratio FW 0.21±0.01, HW 0.21±0.01 (N = 10); blue band at the costa FW 9.8±0.8, HW 9.6±0.8 (N = 10); ratio width of blue band/wing length: FW 0.12±0.01, HW 0.13±0.01 (N = 10).

Coloration in life. Eyes in life bicolored: dorsal half dark green almost turning black, ventrally light green. Ocelli dark brown-yellow. Ventral yellow coloration of tergites sometimes continues to S6. Tibia yellow. Paraproct light brown.

Range. All M. brevistigma specimens were located at the east side of the Andes leading towards the Amazon Basin. In Colombia, museum samples from Bogota were assigned to M. brevistigma and M. caerulatus , which allows the assumption of possible overlapping regions.

Figures

FIGURE 3. Megaloprepus latipennis color patterns: (a) lateral view of prothorax, pterothorax including mesostigmal plates, wing base and coxa; (b) dorsal view of prothorax. al: prothorax anterior lobe. pl: prothorax posterior lobe. mp: mesostigmal plates. cx1–3: coxae.

FIGURE 4. Megaloprepus brevistigma color patterns: (a) lateral view of prothorax, pterothorax including mesostigmal plates, wing base and coxa; (b) dorsal view of prothorax. al: prothorax anterior lobe. pl: prothorax posterior lobe. mp: mesostigmal plates. cx1–3: coxae.

FIGURE 6. Left hindwings of the four Megaloprepus species. The metallic blue wing band proximal of the pseudostigma was integrated to visualize its variation, whereas the additional matte white band of M. caerulatus could not be pictured (but see Fig. 9). The scale bar indicates 1 cm.

FIGURE 7. Ventral and lateral views of the genital ligula of the four Megaloprepus species. M. caerulatus, M. latipennis and M. brevistigma show significant differences in the inner process of the third segment (s3), M. diaboli sp. nov. constitutes an intermediate position. The scale bar indicates 100 μm.

FIGURE 8. Lateral views of the male caudal appendices. The scale bar indicates 0.1 cm.