Chalastonepsia vumanhi Kazandzhieva, 2025

Kazandzhieva, Svetlozara, Langourov, Mario, Bechev, Dimitar & Nguyen, Hieu Van, 2025, A new species of Chalastonepsia Søli, 1996 (Diptera, Mycetophilidae) from Vietnam, Biodiversity Data Journal 13, pp. e 153645-e 153645 : e153645-

Chalastonepsia vumanhi Kazandzhieva sp. nov.

Materials

Type status: Holotype. Occurrence: catalogNumber: BG-NMNHS-ENT- 000000019865 ; recordedBy: Svetlozara Kazandzhieva; individualCount: 1; sex: male; lifeStage: adult; preparations: In ethanol; occurrenceID: 23E47D56-7971-56E6-ACE0-48E29A57875C; Taxon: scientificName: Chalastonepsia vumanhi ; order: Diptera ; family: Mycetophilidae ; genus: Chalastonepsia ; specificEpithet: vumanhi ; scientificNameAuthorship: Kazandzhieva; Location: country: Vietnam; stateProvince: Phu Tho; verbatimLocality: Tam Dao NP, Tam Đ ảo, ab Chùa Vàng Tam Đ ảo; verbatimElevation: 1067 m; verbatimLatitude: 21°27.6348'N; verbatimLongitude: 105°38.9184'E; verbatimSRS: WGS 84; decimalLatitude: 21.46058; decimalLongitude: 105.64864; Identification: identifiedBy: Svetlozara Kazandzhieva; dateIdentified: 2024; Event: samplingProtocol: flight interception trap; eventDate: 16-10-2023; habitat: lower mountain dipterocarp forest; Record Level: collectionID: BG-NMNHS-ENT- 000000019865; institutionCode: NMNHS; collectionCode: Insects; basisOfRecord: PreservedSpecimen

Description

Male Body length 2.4 mm

Head (Fig. 2 B): Head mostly dark brown, palpi, labella and occiput paler. Antennae yellow; scape, pedicel and the apical five flagellomeres slightly darkened. Ocelli three, virtually in one line, the median one about half the diameter of each lateral one, separated from eye margin and the median ocellus for a distance of about 1.5 times their own diameter. Eyes emarginate above base of antennae, covered with fine hairs. Frons bare. Face densely bristled, shield-like. Clypeus bare, rectangular, longer than broad, not longer than face. Mouthparts reduced, setose, with one visible palpomere. Antennae strongly pectinate, with 14 flagellomeres. Flagellomeres 1–9 each with long anterior projections (Fig. 2 B). Flagellomere 10 only slightly extended, projection about half its diameter. Flagellum mostly light yellow, last 5 flagellomeres darker, flagellar projections apically darkened. Flagellomeres 11–14 not modified. All flagellar segments covered in fine setae about as long as the diameter of the projections apically. Scape and pedicel with some stronger short anterior bristles and less, but longer posterior bristles. Antenna about 1.2 times as long as thorax. Postcranium and genae bristled, with a distinct furrow between median ocellus and tip of the frontal tubercle. No suture present between eye margin and lateral ocellus.

Thorax: Mostly dark brown; upper half of anepisternum paler, upper end of anepimeron light yellow, edges of the mediotergite paler. Anepimeral cleft distinct. Scutum evenly covered with relatively short setae (only three of them left, all the rest – lost), with two paler acrostichal stripes. No prescutal suture. Scutellum with a transverse row of 12–15 stronger setae (most of them lost) and with numerous weaker setae scattered over upper half. Mediotergite bare. Laterotergite with 12 setae medially, most of them lost. Anepisternum bare. Nine pro-episternal bristles present, 2–3 setae on anteprononutum. Pro-epimeron brown, bare, basisternum 1 light yellow, katepisternum brown, bare. Metanotum, metepimeron and metepisternum light yellow with no visible setae, except for one near base of halters. Wings (Fig. 2 C): Length 2.3 mm, width 1.1 mm. Wing unmarked, hyaline, with dense irregularly arranged microtrichia, without macrotrichia, R 1 and R 4 + 5 with a line of setae above. Other postcostal veins without setae. C produced for about one third of the distance between R 4 + 5 and M 1, hardly reaching wing tip. Sc long, ending in R 1 well before base of Rs. Rs distinct, about ¾ as long as crossvein r-m. M-branches reaching wing margin; M 1 about five times (5.5 times) as long as M-petiole, M 2 a little shorter. Point of furcation of CuA beyond base of crossvein r-m. M-petiole, M 1, M 2 and M 4 weak; CuA more distinct. CuP faint, ending at about level of CuA-furcation, A 1 stronger ending before CuA-furcation. Halteres pale yellow, whitish, covered with short hairs, very fine at apical part. Legs: Entirely yellow, except for a dark apical patch on inner side of fore- and mid-coxae and predominantly on inner side of hind coxae. Hind coxae with a complete vertical row of setae (8 or 9) along outer hind margin. Fore tibia as long as fore femur. Spurs yellow, covered in short fine hairs. Spur formula after Vockeroth (1980): 1.3; 1.25, 2.25; 1.2, 2. Antero-apical tibial organ of fore- and mid-tibia missing. Fine tibial and tarsal setae irregularly arranged, dark. Fore leg without strong bristles, except for 5–6 apically on tibia. Tibiae and tarsomeres 1–4 of mid- and hind leg with rather short, but distinct bristles, most of which arranged in lines, the longest about half as long as tibial diameter at apex. These bristles strongly modified, bearing 4–5 narrow leaf-like lateral processes (see fig. 8, Kallweit (1998)). Tarsal claws each with two larger and one smallеr ventral tooth. Empodium small. Abdomen: First segment pale yellow, other segments brown, subapically darker. Sternites 1 and 8 bare. Tergite 1, segments 2–7 and tergite 8 covered with dark setae, most of them lost. Sternites 2 to 6 each with a pair of pale yellow, well-defined, submedian lines. Sternite 6 with fold-lines on basal quarter only. Segments 6–8 reduced. Terminalia (Fig. 3 A – C): Terminalia brown. Tergite 9 large, not fused with gonocoxites, about 1.8 times as wide as long; not rounded apically, straight, slightly concave; dorsally and apical quarter ventrally with setae. Cerci rounded, apically with few setae. Hypoproct rounded, not subtriangular, with 2–3 setae on either side of apex. Parameral apodemes long, curved outwards. Parameres with seven short setae near base. Parameres and aedeagus not clearly separable. Aedeagus stalk-like, elongate, narrow. Gonocoxites fused ventrally, with dark dense bristling, except for a bare median stripe. Posteromedially to gonocoxites, a pair of heavily sclerotised oval appendages, rounded apically with less distinct dent than in C. hokkaidensis (see fig. 11, Kallweit (1998)), each with three short median bristles. Gonostylus small, 1.7 times longer than wide, apically convex, setose basally, with eight distinct setae subapically before the protruding apical part; bearing a brush of around 9–10 finger-like thick setae.

Female. Unknown.

Diagnosis

Chalastonepsia vumanhi sp. nov. differs most conspicuously from the other representatives of the genus, by flagellomeres 1–9 with long anterior projection and details on the genitalia. The new species C. vumanhi sp. nov. is closely related to C. hokkaidensis , sharing the complex structure of the genitalia, but differing in the number of long anterior projections on flagellomeres ( C. hokkaidensis 1–10, C. vumanhi sp. nov. 1–9), in the shape of T 9 (in C. hokkaidensis apically rounded and slightly tapering, in C. vumanhi sp. nov. straight and slightly concave – Fig. 3 D), the shape of hypoproct rounded apically, not subtriangular (Fig. 3 D); shape of heavily sclerotised appendages more round, rounded apically with less distinct dent (Fig. 3 C); parameral apodemes long and slightly curved outwards, parameres baring seven setae. Aedeagus more elongate and narrower, stalk-like (Fig. 3 A). Gonostylus small, longer than wide apically convex with eight distinct setae subapically before the protruding apical part (Fig. 3 B); subapically with a brush of around nine finger-like thick setae.

From C. orientalis Søli , it differs in having pectinate antennae, wing vein M 2 complete, a much shorter posterior fork, absence of an antero-apical organ on fore- and mid-tibia, presence of strong tibial setae and characteristics of the complex terminalia.

From C. montana , it differs in the number of long anterior projections on flagellomeres ( C. montana 1–11, C. vumanhi sp. nov. 1–9), colouration of the body (no yellow areas on scutum and lateral thoracic sclerites), presence of strong tibial bristles and details on the terminalia (different shape of T 9 without setose medial protuberance and shape of gonostylus, gonocoxites, hypoproct and cerci broader and more rounded without long apical setae).

The new species differs from C. nigricoxa in the number and shape of long anterior projections on flagellomeres (in C. nigricoxa 1–8, in C. vumanhi sp. nov. 1–9), colour patterns of thorax and abdomen, yellow coxae and details on terminalia (different shape of gonostylus, apical dark setae not bent, different shape of T 9 without setose medial protuberance, hypoproct and cerci broader and more rounded without long apical setae).

Etymology

The new species is named after the Vietnamese acarologist Manh Quang Vu who helped organising the expedition in Tam Dao National Park where the material was collected.

Distribution

The species is known only from the type locality in northern Vietnam, but considering the wide distribution of the other species in the genus ( Ševčík and Hippa 2010), it is possible that it is present in other localities in the Oriental Region.

Notes

During subsequent handling, the specimen sustained additional damage, resulting in detachment of several legs. They are preserved in a separate microvial and include: one fore-leg (comprising femur, tibia and tarsus), two mid-legs (one of which remains partially attached to the specimen, but lacks distal tarsomeres) and two hind legs (one with missing tarsus).

Figures

Figure 2. Chalastonepsia vumanhi sp. nov. holotype, male (BG-NMNHS-ENT- 000000019865). A habitus; B antennae; C wing. Scale bars: 1 mm (A, C); 0.1 mm (B).

Figure 3. Male terminalia of Chalastonepsia vumanhi sp. nov. A ventral view of gonocoxal outline; B ventral view of gonostylus; C dorso-posterior view; D tergite 9 with hypoproct and cerci. Scale bars: 0.1 mm (A – C). Abbreviations: gcx = gonocoxite, aed = aedeagus, pm = paramere, gcxa = gonocoxal apodeme, gst = gonostylus, hyp = hypoproct, tg 9 = tergite 9, cer = cercus.