Nyctomyia biunguiculata Harbach, 2014

Harbach, Ralph E. & Taai, Kritsana, 2014, Nyctomyia biunguiculata, a new cavernicolous species of tribe Aedini (Diptera: Culicidae) from southern Thailand, Zootaxa 3895 (3), pp. 427-432 : 428-431

Nyctomyia biunguiculata Harbach , sp. n.

Male. Medium-sized mosquito. Dark scaling light to dark brown, pale scaling white to golden. Head: Vertex with large falcate scales and few broad scales laterally, ocular and interocular areas with smaller falcate scales, erect scales slender, golden, borne on occiput and posterior area of vertex; eyes narrowly separated above antennae, 2 prominent interocular setae present; antenna shorter than proboscis, length about 1.75 mm, pedicel and flagellomere 1 with few small spatulate scales on mesal surface, flagellar whorls comprised of numerous long strongly developed setae projecting mainly dorsally and ventrally, flagellomeres 12 and 13 very long, combined length about 0.4 length of flagellum; maxillary palpus slender, about 0.3 length of proboscis, comprised of 4 palpomeres, fourth vestigial, dorsal and lateral surfaces dark-scaled, ventral surface without scales, apex of palpomere 3 with few short setae; proboscis long and slender, length (including labella) about 2.3 mm, distinctly longer than forefemur, about 1.25 times as long. Thorax: Integument light brown, darker dorsally. Scutum with pattern of coarse pale scales on background of fine dark scales, pale scaling as follows: acrostichal line bifurcating posteriorly into lateral prescutellar patches, anterior patch on scutal fossa contiguous with anterior dorsocentral line, posterior scutal fossal line joined to posterior dorsocentral line, and narrow lateral patch extending from prescutal suture onto margin of supraalar area; acrostichal and dorsocentral setae weakly developed, inconspicuous; scutellum with pale falcate scales on mid and lateral lobes; paratergite narrow, without scales and setae; antepronotum with large pale falcate scales, postpronotum with few pale falcate scales on upper anterior corner; brown setae on antepronotum and upper posterior margin of postpronotum; postspiracular setae present; pleura with golden to golden-brown setae on upper proepisternum (8), prealar area (7), upper (7) and lower (7) mesokatepisternum (in more or less continuous row), and upper (9) and lower (3) mesepimeron; pale spatulate scales on upper proepisternum, postspiracular area, upper and lower mesokatepisternum, and upper anterior mesepimeron between upper and lower mesepimeral setae. Wing: Length about 2.8 mm, width about 0.5 mm; entirely dark-scaled, veins with few scales, tertiary fringe scales absent; remigium without setae; alula with narrow scales on margin. Halter : Integument pale, capitellum darker dorsally with faint pale scales. Legs: Anterolateral surface of forecoxa with pale spatulate scales and prominent brown setae, midcoxa with pale spatulate scales on anterior side of mid-lateral row of prominent brown setae, hindcoxa without scales, with posterolateral row of prominent brown setae; femora with narrow indistinct apical pale knee spots, forefemur length about 1.8 mm; tibiae and tarsi dark-scaled; tarsomere 5 of both forelegs missing but foreungues probably like midungues (vide Harbach et al., 2007), midungues enlarged, anterior and posterior unguis of each with a tooth, hindungues small, equal, simple. Abdomen: Tergum I with median dorsal patch of pale and dark scales, laterotergite with patch of white spatulate scales; terga II–VII with relatively narrow straight basal pale bands, tergum VIII (post-rotation ventral position) mainly dark-scaled, posterior margin straight; sterna II‒VII with basal pale bands, bands nearly 0.5 length of respective sternum, sternum VIII (post-rotation dorsal position) mainly pale-scaled, posterior margin straight. Genitalia ( Fig. 1 ): Tergum IX lobes poorly developed, separated, each with row of small setae along posterior margin; sternum IX (not illustrated) about as long as broad, with median pair of setae about 0.75 from anterior margin; gonocoxite elongate, mesal membrane developed to apex, basal dorsomesal lobe slightly produced with dense cluster of relatively long setae, dorsal surface with sparse short setae, lateral and ventral surfaces with long setae and spatulate scales, apicodorsal lobe not developed; gonostylus long, about 0.70 length of gonocoxite, slender at base, expanded laterally in distal 0.45, proximal portion with few widely spaced ventromesal setae, expanded portion with uneven lateral line of close-set simple setae, some longer ventromesal setae and a slightly subapical pair of stout gonostylar claws, claws about 0.1 length of gonostylus; claspette slender, apex with 2 stout relatively short setae and 1 or 2 slender setae; proctiger well developed, about 0.3 length of gonocoxite, paraproct tapered and bent tergad, without apical teeth; cercal sclerite faintly developed (not illustrated), more or less membranous, fused with paraproct, cercal setae absent; tergum X distinct; aedeagus relatively large, located mostly anterior to proctiger in resting position, lateral plates bent tergad, joined distally, apical tergolateral margin of each with line of short ridge-like teeth.

Female, egg, larva and pupa. Unknown.

Etymology. Latin, bi - (two or double) and unguiculata (with a small claw), literally meaning “double little claw”, in reference to the pair of gonostylar claws of the male genitalia.

Bionomics. The holotype male of Nc. biunguiculata was reared from a pupa collected from a rimstone pool (0.5 x 0.5 m, depth 35 cm) located 50 m inside Wat Sumano cave , Srinagarindra District , in Phatthalung Province of southern Thailand. The water in the pool was clear, cold and devoid of vegetation and plant matter. The cave harbours numerous bats that are likely to be the primary source of food for adult females. The species has not been found outside the cave .

Distribution. Nyctomyia biunguiculata is only known from the Wat Sumano cave in Phatthalung Province of southern Thailand ( Fig. 2 ).

Holotype. Male, with pupal exuviae (partially decomposed and over cleared) and dissected genitalia on separate microscope slides, THAILAND: Phatthalung Province, Srinagarindra District, Wat Sumano cave (07º 35' 10.4" N, 99º 52' 6.5" E), rimstone pool (0.5 x 0.5 m), 15.iv.2011 (M. Isenstadt). Deposited in the Natural History Museum, London.

Figures

FIGURE 1. Male genitalia of Nyctomyia biunguiculata (tergal view), right gonocoxopodite not drawn and mid-section of tergum IX omitted to show internal structures. Ae = aedeagus; Cl = claspette; Gc = gonocoxite; GC = gonostylar claws; Gs = gonostylus; Par = paramere; Ppr = paraproct. Scale bar = 0.1 mm.

FIGURE 2. Outline map of Thailand showing the locations (black dots) of Wat Tham Panthurat, type locality of Nc. pholeocola, in Surat Thani Province (1), and Wat Sumano cave, type locality of Nc. biunguiculata, in Phatthalung Province (2). The type localities of the other Thai troglobite species are indicated as follows: ▲= Culex harrisoni (Chiang Dao cave, Chiang Dao District, Chiangmai Province); ♦ = Borichinda cavernicola (Borichinda cave, Chomthong District, Chiangmai Province); ♥ = Isoaedes cavaticus (Gang Lawa cave, Sai Yok District, Kanchanaburi Province).