Megalestes, Selys, 1862

Yu, Xin & Xue, Junli, 2020, A review of the damselfly genus Megalestes Selys, 1862 (Insecta: Odonata Zygoptera: Synlestidae) using integrative taxonomic methods, Zootaxa 4851 (2), pp. 245-270 : 266-267

Key to male Megalestes

1 Color of cercus yellow ( Fig. 3m ); genital ligula with large middle lateral lobes ( Fig. 5z ) and obvious basal lateral lobes ( Fig. 5 aa)............................................................................................. riccii

- Color of cercus black or dark brown; genital ligula without obvious basal lateral lobes, middle lateral lobes relatively small or absent.............................................................................................. 2

2 Paraproct without basal tooth, straight and strong, longer than 1/2 the length of the cercus ( Fig. 6c )............... gyalsey

- Paraproct with basal tooth, never straight, seldom as long as 1/2 the cercus length.................................. 3

3 Horns present at the end of genital ligula ( Fig. 5n )........................................................... 4

- Horns absent at the end of genital ligula, or only having lateral lobes............................................ 7

4 Distinct inner lateral tooth present at the middle of cercus ( Fig. 3h ), paraproct almost spherical ( Figs. 4h ; 6e )........ major

- No lateral tooth at middle of cercus, apex of paraproct produced, not spherical..................................... 5

5 Paraproct apex truncate, extended transversely, serrated with some hairs, a brushlike appearance; basal tooth large with end pointed ( Figs. 4g ; 6d ); end of the genital ligula narrow, with the margin rounded ( Fig. 5t )...................... kurahashii

- Paraproct apex pointed; end of the genital ligula broad with the margin trapezoidal................................. 6

6 Basal tooth of paraproct robust, longer than 1/2 the entire length of paraproct, with end pointed forward ( Figs. 4b ; 6l ); genital ligula with obvious terminal lateral lobes ( Fig. 5s )........................................................ irma

- Basal tooth of paraproct very small, shorter than 1/3 the entire length of paraproct, with end pointed upward ( Figs. 4a , 6a ); genital ligula without terminal lateral lobes ( Fig. 5a, a 1 )................................................. australis

7 Dorsum of 10 th abdomen segment normal, not swelling................................................. lieftincki

- Dorsum of 10 th abdomen segment more or less swelling ( Fig. 4d )............................................... 8

8 Paraproct short with apex obtuse, covered with long, dense hairs that entirely cloak the apex; basal tooth of paraproct strong with base bulged and apex very acute pointed upward or a little forward (this character varied to some degree, cf. Figs. 4k and l and 6i and j ); end of genital ligula modestly broad, elongate, and concave like a spoon; modest middle lateral lobes present but no basal and terminal lobes ( Fig. 5w and x )............................................................ micans

- Paraproct produced back-upward with apex pointed or a little blunt; basal tooth of paraproct conical; end of genital ligula not elongate like a spoon; terminal lateral lobe present but basal or middle lobes absent................................. 9

9 Apex of paraproct somewhat blunt with sparse hairs mainly on the tip ( Fig. 4i and j ); end of genital ligula horizontal, broad, margin truncated, with small terminal lateral lobes ( Fig. 5u and v )............................................. haui

- Apex of paraproct pointed with sparse hairs mainly on the rear side; end of genital ligula not at horizontal level......... 10

10 Apex of the cercus extended; basal prominence long, cylindrical with the end foot-like ( Figs. 3 c–d and 4c–d); basal tooth of paraproct long and strong, at least as long as the produced paraproct apex ( Figs. 3c and d ; 4c and d ); end of genital ligula narrow, slightly spoon-like, with terminal lateral lobes divergent largely, up-curved at tips ( Fig. 5o )...................... distans

- Apex of the cercus normal; basal prominence short, flat, somewhat rectangular; end of genital ligula not spoon-like...... 11

11 End of genital ligula broad, terminal lateral lobes very large and bent forward like wings ( Fig. 5p ).................. heros

- End of genital ligula narrow, terminal lateral lobes small and wrapping genital end tightly ( Fig. 5q )............. omeiensis

Figures

FIGURE 1. Distribution of the species of genus Megalestes.

FIGURE 3. Caudal appendages of males (dorsal view). a) australis; b) irma, paratype; c) distans, from Yaan, Sichuan; d) distans from Dashahe, Guizhou; e) heros; f) omeiensis, paratype; g) kurahashii; h) major; i) haui; j) “palaceus”; k) micans, bd: basal disk; l) “chengi”; m) riccii; n) “maai”; o) “tuska,” from Damingshan, Guangxi; p) “tuska,” from Jinxiu, Guangxi. (Scale bar = 0.5 mm).

FIGURE 4. Caudal appendages of males (lateral view). a) australis; b) irma, paratype; c) distans, from Yaan, Sichuan; d) distans from Qingchengshan, Chengdu, Sichuan; e) heros; f) omeiensis, paratype; g) kurahashii; h) major; i) haui; j) “palaceus”; k) micans; l) “Chengi,” paratype; m) riccii; n) maai; o) tuska, from Damingshan, Guangxi; p) tuska, from Jinxiu, Guangxi. (Scale bar = 0.5 mm).

FIGURE 5. Genital ligula of males (lateral view) (a–m) and ventral view (n–ab). a) australis; b) distans; c) heros; d) omeiensis, paratype; e) major; f) irma, paratype; g) “palaceus”; h) haui; i) “Chengi”; j) maai; k) riccii; l) tuska; m) micans; n) australis, Hr: horn; o) distans, Tlb: terminal lateral lobe; p) heros; q) omeiensis, paratype; r) major; s) irma, paratype; t) kurahashii; u) “palaceus”; v) haui; w) micans, from Jinping, Yunnan; x) “Chengi”; y) maai; z) riccii, Blb: basal lateral lobe; aa) tuska, Mlb: middle lateral lobe; ab) micans, from Fengyangshan, Zhejiang. (Scale bar = 0.2 mm).

FIGURE 6. Line drawing of male paraprocts (lateral view). a) australis; b) distans; c) gyalsey; d) kurahashii; e) major; f) haui; g) heros; h) omeiensis; i) micans; j) micans; k) riccii; l) irma.