Pseudagrion igneum, Seehausen & Kalkman & Bedjanič, 2025

Pseudagrion igneum sp. nov.

Figures: 43 (habitus holotype ♂); 44–46 (S9–10, caudal appendages holotype ♂); 47 (head holotype ♂); 48 (pronotum holotype ♂); 87 (head ♂); 104 (pterothorax ♂); 121a, b (abdomen ♂); 138a–c (caudal appendages ♂); 161–162 (field photos ♂).

Pseudagrion pilidorsum : Hämäläinen et al. (1999): 28 (Middle Andaman; subspecific status remains to be studied);— Koparde et al. (2018): 41, Figs 2g, 3d (North Andaman; map; photo ♂ alive, habitat photo).

Holotype: ♂, 8.xii.1998, Chiriyatapu , South Andaman, India, approximately 11.503°N, 92.702°E, ex. Coll. M. Hämäläinen, Wen-Chi Yeh, no. 1152912. Deposited at Naturalis Biodiversity Center Leiden, the Netherlands. GoogleMaps

Paratypes (2♂♂): 2♂♂, 9.xii.1976, rivulet near Asmadabad , South Andaman, India, RMNH, no. 1552773 .

Etymology: The name refers to the fiery impression of the bright red thorax colouration of mature males ( Figs 161, 162).

Remarks

Matjaž Bedjanič observed a male of this species at a stream along the Mayabunder-Diglipur section of the Great Andaman Trunk Road in the North Andaman (13.1872°N, 92.8893°E; Figs 161, 162). This stream is about one metre wide, with sparse bank vegetation, and the surroundings are covered by forest. The locality is situated about 5 km SW of the locality where the species has been observed a month later by Koparde et al. (2018), and approximately 80 km N of the species’ locality in the Middle Andaman, where a male of the species was collected in June 1997, and reported by Hämäläinen et al. (1999). It is expected that with further targeted fieldwork in the right season and in suitable habitats, the species will be found at additional localities on the Andaman Islands. However, as the newly described Pseudagrion is a colourful and quite conspicuous damselfly, the fact that only records of six males are known to date, and that rather recent fieldtrips of M. Bedjanič and P. Koparde, P. Dawn and A. Sumanapala in monsoon season of 2017 yielded only one observation each, suggest that the species is rather local. Additional information on distribution, biology, phenology, and habitat requirements is needed for relevant assessment of threat status of this interesting new endemic.

Other species recorded at the locality were: Vestalis gracilis ( Rambur, 1842) , Copera marginipes ( Rambur, 1842) , Prodasineura verticalis andamanensis ( Fraser, 1924) , Tetrathemis platyptera Selys, 1878 , and Trithemis aurora ( Burmeister, 1839) .

Description of holotype male

Head ( Fig. 47, also compare Fig. 87): Labium, mandibles, genae, labrum, anteclypeus, postclypeus, antefrons, and postfrons yellow; yellow of postfrons sharply separated at level of median ocellus; vertex black, bordered by an orange-reddish rhombus along the ocelli; a black spot posterior of the median ocellus; followed posteriorly by a large orange-reddish spot, elongated to level of posterior end of lateral ocelli; postocular spots orange-reddish, bordered by black; rear of head black, but narrow yellowish along the eye margins; base and scape of antennae yellow, pedicel brownish, rest of antennae missing.

Thorax ( Figs 43, 48, also compare Fig. 104): Anterior lobe of pronotum orange, with its anterior margin black; middle pronotal lobe black, an orange-reddish patch in the middle centrally divided by a black line, and on either side an orange-reddish patch dorsolaterally; propleuron black above, orange below and to rear; posterior lobe of pronotum orange; apical edge of posterior lobe convex. Pterothorax orange; middorsal carina thin black; mesopleural suture with an elongated black patch at posterior third; interpleural suture thin black, with a small dark spot anteriorly; metapleural suture with an elongated black patch at posterior third; mesinfraepisternum pale orange, its superior and posterior edge black; venter of pterothorax yellow-orange, covered with whitish pruinosity. Legs yellowish-ochre, outer side washed with a blackish stripe; tip of tarsi and tarsal claws brown; spines blackish.

Wings ( Fig. 43): Membrane hyaline; veins brown to black; 12.5 px in right forewing, left forewing damaged; 11.5 px in both hindwings; Pt dark reddish-brown, overlying one cell.

Abdomen ( Fig. 43, also compare Figs 121a, b): S1 dorsally washed out blackish, laterally orange; S2 dorsally black, apically the black expanded laterally, otherwise laterally orange; S3–8 dorsally black, apically on each segment the black expanded laterally; each segment laterally pale white-yellowish, except for S8 which is laterally orange; each segment with a narrow pale white-yellowish basal annulus; S9 orange, with its posterior third dorsally and laterally black; S10 ( Figs 44, 45) with a black posterior margin, and a black middorsal stripe making a “Y”-like marking dorsally; laterally a faint and very narrow black stripe, fading anteriorly, separating two yellow-orange dorsolateral patches.

Caudal appendages ( Figs 44–46, also compare Figs 138a–c): Cercus laterally washed-out blackish, slightly shorter than S10, inferior lobe appearing slightly shorter than superior lobe; in lateral view cercus subrectangular, apex with a broad inter-lobe notch; in dorsal view cercus appears narrow, apex of superior lobe slightly pointed and curved inwards, a subtriangular interior projection is situated just proximal of the middle of the cercus; a small, tooth-like subbasal interior projection before half-length of the inferior lobe of the cercus, visible in dorsal and dorsolateral views; paraproct pale yellow-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 prominent black tooth at blackish medial edge.

Measurements (mm): Total length (with appendages) 39.3; abdomen length (without appendages) 32.2; hindwing 21.5; forewing 22.8; Pt in forewing 0.8; cercus 0.6.

Variation in paratype males

Wings: 13.5–14 px in forewing, 10.5–12.5 px in hindwing.

Abdomen: Dorsal black on S9 may be expanded to the posterior half.

Measurements (mm): Total length (with appendages) 40.3–42.5; abdomen length (without appendages) 34.3– 35.0; hindwing 22.2; forewing 23.8; Pt in forewing 0.8; cercus 0.5–0.6.

Female unknown.

Diagnosis

Pseudagrion igneum is separated from its Nicobar congeneric P. nigrihumerale by lacking a broad black humeral stripe ( Figs 104, 105), S1–2 of the abdomen dorsally black, S10 red with black dorsal marking ( Figs 121a, b, 122a, b), as well as by red on vertex and postfrons ( Figs 87, 88), whereas the male caudal appendages are identical in both species ( Figs 138a–c, 139a–c). Also the male cerci of P. simalurum and P. obscurum are almost identical, seemingly with only a tiny different: the cercus of P. igneum bears a small subbasal tooth before half-length of the inferior lobe, whereas in P. obscurum and P. simalurum there is a sharp edged bulge that only looks like a tooth in dorsal view ( Figs 140a–c, 141a–c). Additionally P. igneum lacks a darkened dorsum of the pterothorax as it is in P. obscurum ( Fig. 106). See also table 2 under P. obscurum for further information. All other species are separated by the morphology of the male appendages, and partly by the colour markings of head, thorax, and abdomen.

Distribution

Apparently endemic to the Andaman Islands, India ( Fig. 2).