Pseudagrion pilidorsum Brauer, 1868

Pseudagrion pilidorsum Brauer, 1868 View in CoL

Figures: 63–65 (syntype ♂, labels); 92 (head ♂); 109 (pterothorax ♂); 126a, b (abdomen ♂); 143a–c (caudal appendages ♂); 165–166, [167?] (field photos ♂).

Agrion pilidorsum View in CoL : Brauer (1868): 553 –554 (description ♂ ♀; Manilla, Luzon ) .

Pseudagrion pilidorsum View in CoL : Selys (1876): 514 –515 (description ♂; Manilla, Luzon);— Selys (1882): 30 (Manilla, Luzon, Mindanao);— Selys (1891): 217 (Sibul, Irocin, Bulacan);— Ris (1915b): 97, 99 (key; Negros Island, Taiwan);— Ris (1916): 43 –44 (Taiwan);— Lieftinck (1936): 129, 132, Fig. 12a (♂ appendages; key; Mindanao & Basilan, Philippines);— Needham & Gyger (1939): 281 –283, plate 16, Figs 221 & 222 (♂ appendages; several Philippine Islands);— Asahina (1964): 520 (Ryukyu Islands, Japan);— Hämäläinen & Müller (1997): 261 (25 Philippine islands listed);— Dow (2006): 10 ( Sarawak, Malaysia);— Dow & Singa (2022): 20 ( Sarawak & Sabah, Malaysia; East Kalimantan, Indonesia).

Name-bearing type specimen examined (1♂) ♂ syntype, Manila, Luzon Island , Philippines, Brauer det., NHMW ( Figs 63–65) .

Other specimens examined (99♂♂, 39♀♀)

Japan, Ishigaki Island: 1♂, 15.vii.1969, Ishigaki Island, Tora river , Okinawa, H. Kuwahara leg., Coll. von Rosen, ZSM, no. GvRosen 3334 .

Philippines, Basilan Island: 1♀, 2.xii.1914, Basilan , G. Boettcher leg., SMF, no. 13999 ;— 2♂♂, 2.–8.xii.1914, Basilan , G. Boettcher leg., SMF, no. 13992, 13993 ;— 1♂, 1♀, 10.xii.1914, Basilan , G. Boettcher leg., SMF, no. 13997, 13998 ;— 6♂♂, 1♀, 12.xii.1914, Basilan , G. Boettcher leg., SMF, no. 13988–13991, 13994–13996 .

Philippines, Camiguin Island: 2♂♂, 1♀, 22.vii.1916, Camiguin, G. Boettcher leg., SMF, no. 13968–13970 .

Philippines, Leyte Island: 1♀, iv.1915, Burauen, G. Boettcher leg., SMF, no. 13987 ;— 2♂♂, 1♀, 1.–7.v.1915, Burauen, G. Boettcher leg., SMF, no. 13983–13985 ;— 1♀, 7.v.1915, Burauen, G. Boettcher leg., SMF, no. 13986 .

Philippines, Luzon Island: 1♂, Hotspring, ZMUK ;— 1♂, Lamao , ZMUK ;— 1♂, 1♀, Mount Makiling , Baker leg., SMF , no. 19841, 29843;— 2♂♂, 21.x.1913, Limay , G. Boettcher leg., SMF , no. 13948, 13949;— 1♂, 24.ii.1914, Los Banos , G. Boettcher leg., SMF , no. 13982;— 2♂♂, 16.v.1914, Trinidad, G. Boettcher leg., SMF , no. 13953, 13954;— 1♂, 18.v.1914, Trinidad, G. Boettcher leg., SMF , no. 13960;— 1♂, 21.vii.1914, Los Banos , G. Boettcher leg., SMF , no. 13981;— 1♂, 23.vii.1914, Los Banos , G. Boettcher leg., SMF , no. 13980;— 1♂, 11.viii.1914, Mount Banahao , G. Boettcher leg., SMF , no. 13977;— 1♂, 1♀, 12.viii.1914, Mount Banahao , G. Boettcher leg., SMF , no. 13978, 13979;— 1♀, 30.viii.1915, Kasiguran , G. Boettcher leg., SMF , no. 13976;— 1♂, 24.v.1916, Imugan , G. Boettcher leg., SMF , no. 13975;— 1♂, ix.1917, Mount Bulusan , G. Boettcher leg., SMF , no. 13967;— 5♂♂, 21.iii.1978, River , hidden valley N Alaminos, 120 m a.s.l., G. von Rosen leg., ZSM , no. 5523–5527.

Philippines, Marinduque Island: 14♂♂, 2♀♀, i.–ii.1997, Batingon river , near Buenavista, 150–200 m a.s.l., Coll. von Rosen, ZSM , no. GvRosen 12562, 12565–12575, 12577, 12578, 15263–15264;— 1♂, iv.1997, Mandiling, Buenavista, SMF .

Philippines, Masbate Island: 1♂, 30.viii.1916, Aroroy, G. Boettcher leg., SMF, no. 13950 .

Philippines, Mindanao Island: 1♀, Surigao, Baker leg., SMF, no. 29842 ;— 1♂, 1♀, 6.ii.1915, Dansalan [Marawi], G. Boettcher leg., SMF, no. 14005, 14006 ;— 2♂♂, 2♀♀, 7.ii.1915, Dansalan [Marawi], G. Boettcher leg., SMF, no. 14003, 14004, 14012, 14013 ;— 1♂, 1♀, 8.ii.1915, Dansalan [Marawi], G. Boettcher leg., SMF, no. 14007, 14008 ;— 3♂♂, 8.–10.ii.1915, Dansalan [Marawi], G. Boettcher leg., SMF, no. 14000–14002 ;— 3♀♀, 10.ii.1915, Dansalan [Marawi], G. Boettcher leg., SMF, no. 14009–14011 ;— 2♀♀, 20.ii.1915, Momungan, G. Boettcher leg., SMF, no. 13964, 13965 ;— 1♂, 18.vi.1915, Tankulan, G. Boettcher leg., SMF, no. 13962 ;— 1♂, 19.vi.1915, Tankulan, G. Boettcher leg., SMF, no. 13961 ;— 14♂♂, 3♀♀, 21.v.1915, Surigao, G. Boettcher leg., SMF, no. 14027–14043 ;— 1♀, 26.v.1915, Surigao, G. Boettcher leg., SMF, no. 14044 ;— 1♀, 14.vii.1915, Momungan, G. Boettcher leg., SMF, no. 13945 ;— 2♀♀, 11.xi.1915, Surigao, G. Boettcher leg., SMF, no. 14045, 14046 ;— 9♂♂, 4♀♀, 26.iii.1978, Eden, W. Davao, 50 m a.s.l., G. von Rosen leg., ZSM, no. GvRosen 5543, 5544, 5566–5572, 5575–5578 .

Philippines, Mindoro Island: 1♂, 25.i.1916, Subaan, G. Boettcher leg., SMF, no. 13966 ;— 1♂, 1♀, xi.1917, Mangarin, G. Boettcher leg., SMF, no. 13952, 13963 .

Philippines, Panaon Island: 1♀, 8.xii.1915, Panaon, G. Boettcher leg., SMF, no. 13946 .

Philippines, Polillo Island: 5♂♂, 12.–20.viii.1915, Polillo, G. Boettcher leg., SMF, no. 13955–13959 .

Philippines, Samar Island: 2♂♂, 18.iv.1915, Catbalogan, G. Boettcher leg., SMF, no. 14014, 14015 ;— 2♀♀, 18.–24.iv.1915, Catbalogan, G. Boettcher leg., SMF, no. 14024, 14025 ;— 2♂♂, 19.–22.iv.1915, Catbalogan, G. Boettcher leg., SMF, no. 14020, 14021 ;— 2♂♂, 21.iv.1915, Catbalogan, G. Boettcher leg., SMF, no. 14022, 14023 ;— 4♂♂, 1♀, 22.iv.1915, Catbalogan, G. Boettcher leg., SMF, no. 14016–14019, 14026 .

Taiwan: 1♀, 15.ix.1907, Koroton , Formosa, H. Sauter leg., UMB ;— 1♂, i.1908, Lambek Island , South-Formosa, H. Sauter leg., ZMH ;— 1♂, 1♀, viii.1908, Taihanroku, Formosa, Sauter leg., SMF , no. 13971, 13972.

In addition to the specimens listed above there are more than 1830 ♂♂ and 270 ♀♀ from the Philippines at the RMNH originating from the following islands: Balabac , Basilan, Batan , Biliran, Camiguin, Catanduan , Cebu, Dinagat, Homonhon , Leyte, Luzon , Marinduque, Masbate, Mindanao , Mindoro , Negros , Palawan, Panaon , Panay , Samar, Sibuyan, Siquijor, Sulu Archipel and Ticao. Data on these will be published as part of a forthcoming checklist and atlas of the dragonflies and damselflies of the Philippines .

Characterization of male

Head ( Figs 64, 92): Labrum, clypeus, antefrons, postfrons and vertex red; postocular spots red, separated by a thin black line from postfrons; rear of head black, with yellow along the eye margins; base and scape of antennae reddish, following segments brownish.

Thorax ( Figs 63, 64, 109): Anterior lobe of pronotum red, this colour expanding in centre towards middle lobe; middle pronotal lobe black, with a centrally divided red patch in the middle, and on either side a large red patch dorsolaterally; posterior lobe of pronotum red; with its apical edge convex. Pterothorax red, with a thin black middorsal carina; humeral suture and metapleural suture each with a black stripe at posterior quarter, both slightly expanded in the middle dorsally and ventrally; metapleural suture may be covered with whitish pruinosity; interpleural suture with a thin black stripe at posterior quarter; venter pale, often covered with whitish pruinosity. Legs with femur and tibia pale reddish-white; femora bearing a black stripe outside reaching from distal margin to proximal half; tibiae blackish along spines; spines black.

Abdomen ( Figs 63, 126a, b, 165, 166): Variable in the whole range but generally with S1 red; S2 red, along its posterior carina black; S3 variable: in specimens from the Philippines, Taiwan, and Japan generally reddish, with variable washed-out blackish dorsal marking at posterior margin; in specimens from Borneo often dorsally black ( Fig. 166); S4 variable: predominantly reddish, with variable washed-out blackish dorsal marking at posterior margin; in specimens from Palawan Islands/ Philippines it may be almost completely black dorsally, but usually at least the anterior margin remains washed-out reddish; in specimens from Japan S4 is dorsally black; S5 variable: Philippine specimens are predominantly black dorsally, but anterior edge may be washed-out with reddish in different extent; specimens from Basilan Island/ Philippines and from Taiwan have S5 reddish with a dark dorsal marking at posterior margin; S6–8 dorsally black; S9 red with posterior quarter to half black, sometimes with edges of black serrated; S10 red, predominantly with a black dorsal “x”-like marking, variable in exact shape; but segment may also be completely black dorsally, with only two small reddish spots (e.g. in a male from Okinawa, Japan).

Caudal appendages ( Figs 143a–c): Cercus laterally washed-out blackish, but may be reddish at base; in lateral view cercus shorter than S10, the upper margin slightly convex, its apex almost square, inter-lobe notch not apparent in this view; in dorsal view the apical part of the superior lobe of the cercus curved inwards and runs as a ridge to the inter-lobe notch, with a separate inward directed projection proximal of this visible in dorsolateral view; another inwardly directed projection is situated more proximally at before the middle of the cercus; the inferior lobe with a ridge, best visible in dorsolateral view; a small bulge-like interior projection at the base of the ridge is visble in dorsal and dorsolateral view; paraproct pale yellow-orange, slightly shorter than cercus; in lateral view subtriangular and tapered, with rounded apex; in dorsal view broadly rounded, concave bowl-like; bearing a black tooth at medial edge.

Characterization of female

Head: Dark markings similar to male, but primary colours pale orange-ochre; postocular spots may be tinged greenish.

Thorax: Pronotum markings as in male, but primary colour orange-ochre instead of reddish; posterior lobe of pronotum with two orange-ochre horns directed towards head, reaching the centre of the middle lobe. Pterothorax with primary colour orange-ochre; dark markings as in male; antehumeral area of pterothorax may be tinged greenish.

Abdomen: S1–2 orange-ochre, with black dorsal markings, variable in size; S3 either orange-ochre, with a black dorsal marking posteriorly, variable in size, or completely black dorsally; S7–8 dorsally black, laterally pale yellowish; S9–10 either black dorsally, or black reduced to “x”-like marking, variable in exact shape; laterally yellow-ochre, this colour expanded dorsally in centre of segment, leaving anterior and posterior margin black. Cercus blackish; paraproct washed-out dark brownish; in lateral view rounded; ovipositor pale yellowish-ochre, not reaching posterior margin of S10, two brownish styles reaching beyond S10; inferior edge of ovipositor bearing several very small teeth.

Wings of both sexes with 11.5–14.5 px in forewing and 9.5–12.5 px in hindwing.

Measurements of both sexes (mm): Total length (with appendages) 38.6–45.8; abdomen length (without appendages) 31.4–37.0; hindwing 21.3–25.7; forewing 22.7–27.8; Pt in forewing 0.7–1.0; male cercus 0.5–0.6.

Diagnosis

The combination of a red clypeus and red frons ( Figs 64, 92), a red pterothorax ( Figs 63, 64, 109, 165, 166), and at least red S1–2, but up to S1–5 red ( Figs 126a, b, 165, 166), makes this species unmistakable. The red clypeus and frons are shared only by P. perfuscatum , but this species has smaller postocular spots and more extensive black on vertex ( Figs 61, 91, 163, 164). Additionally mature males of P. perfuscatum have the pterothorax reddish-brown, covered with pruinosity up to interpleural suture, often a broad blackish humeral stripe ( Figs 61, 108, 163, 164), and S1–2 are dorsally blackish and covered with pruinosity ( Figs 61, 15a, b, 163, 164). [Note: See discussion section for further details regarding populations from Borneo].

Distribution

This species occurs throughout the Philippines and Taiwan, and reaches the southern Japanese Islands, as well as the Malaysian Sabah and Sarawak in northeast Borneo ( Fig. 1).