Chetoneura lagangеnsis Kazandzhieva & Bechev, Kazandzhieva & Bechev, 2022

Kazandzhieva, Svetlozara & Bechev, Dimitar, 2022, A new species of Chetoneura Colless from Borneo (Diptera: Keroplatidae), Zootaxa 5104 (4), pp. 593-599 : 594-595

Chetoneura lagangеnsis Kazandzhieva & Bechev , sp. n.

Figs 1–6

LSID urn:lsid:zoobank.org:pub:15EF1596-90A5-4237-B73B-C3217D728329

Diagnosis. R-M fusion short, tergite IX about twice as long as wide, gonostylus elongate in ventral view, with elongate sharp apical spine. Sc unclear distally. Scutum light yellowish brown, in other species of Chetoneura brown, in Ch. davidi yellowish, with lateral margins and two submedian longitudinal stripes dark. Coxae light, yellowish, in other species brown, in Ch. davidi partly yellowish.

Type material. HOLOTYPE: ♂, MALAYSIA: Sarawak: Gunung Mulu National Park, Lagang cave, 14.07.2019, Sweep net, S. Kazandzhieva leg. (in ethanol, in DBPC – University of Plovdiv , Bulgaria).

Type locality. Lagang cave , Borneo .

Male. Body length 4.3 mm. Wing length 3.15 mm.

Head. Vertex and frons light brownish. Occiput light yellowish brown, lighter close to the eyes. Two ocelli, medially on the vertex, distance between them about their diameter. Compound eyes large, covering most of head surface, with ommatidial hairs. Vertex covered with setulae, frons bare. Upper half of face bare, ventral half covered with dark setulae. Clypeus light yellowish brown, small, projected, with parallel edges proximally, rounded triangular distally, bare. Mouthparts reduced. Labellum and labrum rudimentary. Palpus reduced to single small palpifer and a rounded distal segment with setulae. Antenna about 4.5 times as long as head width, with 14 flagellomeres. Scape and pedicel shorter than flagellomeres, width about twice their length. Flagellum laterally compressed, hairy. First flagellomere (F1) about twice as long as second (F2). F2–F5 about as wide as long, F6–F9 slightly longer than wide, F10–F14 about twice as long as wide.

Thorax. Scutum light yellowish brown. Anterior parapsidal suture pronounced. Scutellum darker, almost as wide as long. Scutum and scutellum evenly covered in setae. Mediotergite light brown, with dark brown setae in dorsal part. Laterotergite light yellowish brown, bare. Antepronotum and proepisternum light yellowish brown, setose. Postepisternum with a few setulae at thе anterior margin. Anterior spiracle with setulae at margin, except dorsally. Anepisternum pale yellowish brown with whitish shades, other tergites pale and bare. Haltere with light yellowish brown pedicel, two rows of oblique setae beginning from base of pedicel, abundant at base of knob. Knob brown at base, brightening towards tip, tip bare.

Wing ( Fig. 2 ). Wing length 3.15 mm, width 1.8 mm. Wing membrane light brown, hyaline, densely covered with microtrichia. Macrotrichia present on C, R 1 and R 4+5, absent on medial veins, CuA and CuP. Radial veins and CuA strong, other veins weaker and lighter. C extending beyond tip of R 4+5 to about half the distance between tips of R 4+5 and M 1, ending at wing apex. Sc weak, unclear at distal end near C. R 4 absent. R-M fusion very short. R 4+5 strong, reaching C before wing apex. R 1 long, reaching C beyond level of medial fork. Medial fork weak and relatively long, about twice the length of M 1+2. M 2 ending at wing margin. M unclear before R-M fusion. CuA strong, distinctly downcurved towards tip. CuP weak, incomplete. A 1 unclear.

Legs. Elongate, mostly light brown, darker near joints. Coxae light, yellowish, with distinct lateral rows of dark bristles, upper half almost bare. Femora pale, darker near joints, laterally flattened, evenly covered with fine short dark bristles. Tibial microtrichia arranged in regular rows, tibial macrotrichia present in irregular rows. Fore tibia without apical spur and apical comb. Mid and hind tibiae with a single setose apical spur and apical comb of setae. Mid spur four times tibial width, hind spur five times tibial width. Tarsal claws with basal teeth. Relative length of femur, tibia and tarsus for particular legs: fore leg—1.6: 2.1: 4.7; mid leg—1.5: 2.1: 3.8; hind leg—1.8: 2.3: 3.8.

Abdomen. Abdomen yellowish brown, strongly covered with hairs.

Terminalia ( Figs 3–6 ). Brown, densely covered with dark setae. Tergite IX elongated, wider at basal half, narrower at apical ( Fig. 3 ). Cerci long. Hypoproct blunt, covered with setae apically. Gonocoxites ventrobasally fused, forming a broad V-shaped excavation, densely covered with setae ( Fig. 5 ). Gonostylus about twice as long as wide, covered with long dark setae, ending with a sharp apical spine, subtriangular in lateral view ( Figs 5–6 ).

Female. Unknown.

Larva. Non-luminescent larvae (probably of the new species) were hanging in the semi-dark cave entrance ( Figs 10–12 ) and deep in the cave as well. Similar larvae were also observed outside the cave ( Fig. 13 ).

Etymology. Named after the type locality, the Lagang cave.

Figures

FIGURE 1. Chetoneura lagangеnsis sp. n., habitus, lateral view.

FIGURE 2. Chetoneura lagangеnsis sp. n., wing, view from below.

FIGURES 3–6. Chetoneura lagangеnsis sp. n., male terminalia: 3—dorsal view, 4—lateral view; 5—ventral view; 6—posterior view. Abbreviation: aps = apical spine of gonostylus; cer = cerci; gcx = gonocoxite; gst = gonostylus; hyp = hypoproct; T9 = tergite IX.

FIGURES 10–13. Larvae, probably of the new species: 10–12—in the entrance, semi-dark part of the cave; 13—outside the cave.