Pseudagrion enganoense Lieftinck, 1948

Seehausen, Malte, Kalkman, Vincent J. & Bedjanič, Matjaž, 2025, Revision of the Pseudagrion red-group occurring in Asia west of Lydekker’s line, with description of four new species (Odonata: Coenagrionidae), Zootaxa 5587 (1), pp. 1-66 : 22-23

publication ID	https://doi.org/10.11646/zootaxa.5587.1.1
publication LSID	lsid:zoobank.org:pub:B6F6D9C8-4423-4DC6-BC25-940725A83DB4
persistent identifier	https://treatment.plazi.org/id/0E57D167-F745-FFE7-FF66-DAADFB6999D0
treatment provided by	Plazi
scientific name	Pseudagrion enganoense Lieftinck, 1948
status	stat. nov.

Treatment

Pseudagrion enganoense Lieftinck, 1948 stat. nov.

Figures: 31–32 (lectotype ♂, envelope); 85 (head ♂); 102 (pterothorax ♂); 119a, b (abdomen ♂); 136a–c (caudal appendages ♂).

Pseudagrion pilidorsum enganoense View in CoL : Lieftinck (1948): 290 –291, Fig. 6 View FIGURES 5–10 (description ♂ ♀; Engano).

Name-bearing type specimen examined (1♂)

♂ lectotype, 30.v.1936, Buahbuah , Enggano Island, RMNH, JvT no. 2816 ( Figs 31–32 View FIGURES 31–32 ) .

Lectotype designation by Lieftinck (1971: 86). Lieftinck (1948) spelled the island “Engano”, that’s why the scientific name is written with a single “g”. However, today the island is spelled “Enggano”.

Other specimens examined (2♂♂)

Indonesia, Enggano Island: 2♂♂, 30.v.1936, Buahbuah, RMNH, no. 1658925, 1658926 .

Characterization of male

Head ( Figs 31 View FIGURES 31–32 , 85 View FIGURES 79–95 ): Labrum, clypeus, antefrons and postfrons yellow; colour of postfrons distinctly separated from vertex around the level of lateral ocelli; vertex red, with a small black spot posterior of median ocellus, and large black patches each along interior and posterior margin of lateral ocelli; postocular spots red, separated by black line from postfrons and vertex; rear of head black, but yellow-orange along the eye margins; base and scape of antennae yellow, following segments brownish.

Thorax ( Figs 31 View FIGURES 31–32 , 102 View FIGURES 96–112 ): Anterior lobe of pronotum yellowish, expanding in centre spot-like towards middle lobe, anterior margin black; middle pronotal lobe black, with a centrally divided yellowish patch in the middle, and on each side a yellowish spot dorsolaterally; propleuron black above, yellowish below and to rear; posterior lobe of pronotum yellowish; apical edge of posterior lobe convex. Pterothorax red, with thin black middorsal carina; humeral suture and metapleural suture with black streaks at posterior quarter; interpleural suture with a thin black line; ventrally pale, may be covered with whitish pruinosity. Legs pale orange-reddish; femora with blackish stripe outside, narrowing proximally; tibiae blackish along spines; spines black.

Abdomen ( Figs 31 View FIGURES 31–32 , 119a, b View FIGURES 113–122 ): S1 red, S2 red with its posterior margin black; S3–8 dorsally black, laterally pale orange-yellow; S9 black with anterior third to half red; S10 black, ventrally pale.

Caudal appendages ( Figs 136a–c View FIGURES 130–139 ): Cercus laterally obscure reddish; slightly shorter than S10, inferior lobe slightly longer than superior; in lateral view subrectangular, apex with inter-lobe notch deep and almost central; in dorsal view cercus appearing narrow, with terminus of superior lobe slightly turned in, bifurcated interiorly (visible in dorsolateral view); a small almost centrally-placed interior tooth-like projection on the inferior lobe of the cercus; paraproct pale ochre; around half as long as cercus; in lateral view subtriangular and tapered with rounded apex; in dorsal view broadly rounded, concave bowl-like, with blackish tubercular medial edge.

Measurements (mm): Total length (with appendages) 42.3–44.5; abdomen length (without appendages) 35.7– 36.7; hindwing 23.7–24.3; forewing 25.0–26.0; Pt in forewing 0.7–1.0; male cercus 0.5–0.6.

Characterization of female [not examined, characterization adopted from Lieftinck (1948)]

Head: As in male but ochraceous instead of yellow.

Thorax: Pterothorax as in male but dorsally honey-yellowish, fading to cinnamon-buff laterally; markings at humeral and metapleural suture rusty.

Abdomen: As in male but with S1–2 orange; S9 with a large yellow spot laterally; ovipositor yellowish.

Wings of both sexes with 14.5–17 px in forewing, and 13–16 px in hindwing [adopted from Lieftinck (1948), and own data].

Diagnosis

Pseudagrion enganoense belongs to the group of endemic taxa of the island chain west of Sumatra. The morphology of the male cercus of P. enganoense is distinct: its inferior lobe is slightly longer than superior one ( Figs 136a, b View FIGURES 130–139 ), and in dorsolateral view the inner margin of superior lobe of cercus lacks an inward projection proximal of its bifurcated terminus ( Fig. 136c View FIGURES 130–139 ). Additionally both sexes of P. enganoense can be separated from congeners on adjacent islands by having S1–2 red in the male ( Figs 31 View FIGURES 31–32 , 119a, b View FIGURES 113–122 ), orange in the female. This character is shared with P. declaratum , P. deflexum , and P. nigrihumerale ( Figs 117a, b, 118a, b, 122a, b View FIGURES 113–122 ). However P. nigrihumerale can also be separated by its broadly black antehumeral stripe ( Fig. 105 View FIGURES 96–112 ), while P. declaratum as well as P. deflexum have much larger red postocular spots than P. enganoense , not bordered by black except for a very small blackish line on vertex ( Figs 26 View FIGURES 26–28 , 29 View FIGURES 29–30 , 31 View FIGURES 31–32 , 83, 84, 85 View FIGURES 79–95 , 155, 157 View FIGURES 155–162 ).