Pseudagrion ustum Selys, 1876

Pseudagrion ustum Selys, 1876 View in CoL

Figures: 78 (holotype ♀); 95 (head ♂); 112 (pterothorax ♂); 129a, b (abdomen ♂); 146a–c (caudal appendages ♂); 168 (field photo ♂).

Pseudagrion ustum View in CoL : Selys (1876): 515 (description ♀; Sulu Island, Malay Archipelago [actual Sula Archipelago, Indonesia]);— Ris (1915b): 97, 99–100, Fig. 21 (key; description ♂; Celebes);— Lieftinck (1930a): 307 (♂ ♀ Buru).

Name-bearing type specimen (not examined)

♀ holotype, Sulu Island , Malay Archipelago [actual Sula Archipelago, Indonesia], IRSNB ( Fig. 78) .

Currently the holotype could not be found at the IRSNB (J. Constant, pers. comm.) .

Other specimens examined (15♂♂, 8♀♀)

Indonesia, Sulawesi: 3♂♂, 1♀, Toli-Toli, SMF , no. 13754–13757;— 1♂, March 1896, Lompa-Battau , 3000’, H. Fruhstorfer leg., ZMH ;— 5♂♂, 4♀♀, 1897, Bonthain, SMF , no. 13743–13747, 13749, 13751–13753;— 1♂, 28.iv.1914, Maros , Dr L. Martin leg., SMF , no. 13933;— 2♂♂, 18.ix.-14.x.1983, Maros, E of Bantimurung area, surroundings of Bantimurung waterfall, 190 m a.s.l., S.S. Pariwono leg., ex. Coll. M.A. Lieftinck, RMNH , no. 1658917, 1658918;— 3♂♂, 3♀♀, 21.ix.-10.x.1983, Maros, E of Bantimurung area, QK94, Patunuang Asue , 250 m a.s.l., S.S. Pariwono leg., RMNH , no. 1519261, 1519262, 1519264.

Characterization of male

Head ( Fig. 95): Labrum, clypeus, antefrons and postfrons yellow; colour of postfrons separated from vertex around level of lateral ocelli; vertex red; black posterolateral patches along each lateral ocellus; postocular spots red, separated by a black line from the postfrons; rear of head black, but pale along the eye margins; base and scape of the antennae yellow, following segments brownish ochre; eyes when alive reddish brown-orange.

Thorax ( Figs 112, 168): Anterior lobe of pronotum orange, this colour expanding in centre towards middle lobe, anterior margin black; middle pronotal lobe black, with a centrally divided large orange patch in the middle, and on either side a large orange patch dorsolaterally; propleuron black above, orange below and to rear; posterior lobe of pronotum orange; apical edge of posterior lobe convex. Pterothorax orange-reddish; middorsal carina black; humeral suture and metapleural suture each with an elongate black patch at posterior quarter, both patches expanded in middle; interpleural suture may have a narrow blackish stripe, and a blackish spot anteriorly; venter pale, may be covered with pruinosity. Legs pale yellowish-reddish with a black stripe at posterior quarter to half of femora; tibiae with black stripe along black spines.

Abdomen ( Figs 129a, b, 168): S1 red, may have a washed-out blackish curly bracket-like patch dorsally; S2 red, but along posterior carina black, often with washed-out blackish marking dorsally at posterior quarter; S3–8 dorsally black, laterally pale yellow-orange; S9 red, with at least its posterior margin, but up to posterior one-third black; anterior margin of black colour may be serrated; some males additionally have two black spots situated dorsolaterally; S10 red, with a black dorsal “x”-like marking, variable in exact shape.

Caudal appendages ( Figs 146a–c): Cercus laterally blackish, slightly shorter than S10, inferior lobe subequal to superior lobe, its apex only just visible in this view; in lateral view superior lobe abruptly narrowing near apex, with inter-lobe notch very small; in dorsal view the cercus broadly rounded; the terminus of the superior lobe curved strongly inwards and somewhat bifurcated, this bifurcation more apparent in dorsolateral view; interior projection of inferior lobe of cercus very large, clearly visible in lateral view where it appears subtriangular and basally positioned; paraproct pale yellow-ochre, slightly longer than half of cercus; in lateral view somewhat triangular and tapered with rounded apex; in dorsal view broadly rounded, concave bowl-like; medial edge with blackish tooth.

Characterization of female ( Fig. 78)

Head: As in male, but orange-ochre instead of yellow and red.

Thorax: Pronotum as in male, but pale yellowish instead of orange-reddish; posterior lobe with apical edge almost triangular-convex; bearing two yellowish horns directed towards the head, almost reaching the centre of the middle lobe. Pterothorax as in male, but when alive dorsum orange-ochre instead of red, and laterally pale greenish-yellow.

Abdomen: S1 orange-ochre, with a black dorsal patch covering anterior two-thirds; S2 orange-ochre, with posterior margin black, and a black middorsal stripe which is expanded patch-like in posterior third; S3–7 dorsally black, laterally pale yellowish; S8 dorsally black, the black may be constricted in posterior third; S9 dorsally black, narrowing posteriorly, laterally pale yellowish; S10 pale yellowish, anterior margin may be black. Cercus pale; paraproct pale, in lateral view rounded; ovipositor pale yellowish, not reaching to posterior margin of S10, two brownish styles reaching beyond S10; inferior edge of ovipositor bearing several very small teeth.

Wings of both sexes with 13.5–16.0 px in forewing, and 11.5–15.5 px in hindwing.

Measurements of both sexes (mm): Total length (with appendages) 44.5–50.8; abdomen length (without appendages) 36.8–42.4; hindwing 24.0–29.7; forewing 25.6–31.2; Pt in forewing 0.8–0.9; male cercus 0.6.

Diagnosis

The morphology of the male cercus ( Figs 146a–c) separates this species from all congeners. Pseudagrion acutidens has also a cercus with a distinct tooth ( Figs 130a–c), but it is directed inward instead of upward as it is in P. ustum . Additionally the colour marking of the pterothorax and of the abdomen separates P. ustum ( Figs 78, 95, 112, 129a, b, 168) in both sexes from P. crocops ( Figs 23, 25, 82, 116a, b, 154), currently the only known other red Pseudagrion species which occurs at Sulawesi.

Distribution

Records of this species are available from Sulawesi, the Sula Archipelago, and Buru ( Fig. 3).