Hybos thaosaeo PLANT 2013, sp. nov.
Creators: name: PLANT, ADRIAN R.
Publisher: name: Zenodo
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Hybotidae
Hybos
Hybos thaosaeo

description: Hybos thaosaeo sp. nov.
(Figs 187–193, 277, 302)
Type material. HOLOTYPE ♂: THAILAND, Petchaburi Province, Kaeng Krachan National Park, km33/helipad, 12°50.177'N, 99°20.688'E, 735 m, 3–10.iv.2009, Malaise trap, Sirichai [T4693] (QSBG). PARATYPES: 1♂, 7♀, same data as holotype, 18–25.i.2009, 3–10.iv.2009, 11–18.v.2009, 18–25.v.2009, 8–15.vi.2009; 1♂, 3♀, Panernthung /km30, 12°49.598'N, 99°21.827'E, 5–12.ix.2008; 1♀, Phanoen Thung Substation, 12°49'25''N, 99°21'54''E, 660 m, 27.vi.2008: 2♂, 10♀, Nakhon Si Thammarat Province, Namtok Yong National Park, TV aerial, 8°14.262'N, 99°48.289'E, 966 m, 7–14.vii.2008, 14–21.vii.2008, 11–18.viii.2008, 18–25.viii.2008, 1–8.x.2008, 15–22.x.2008, 1–8.xii.2008; 1♂, 11♀, hill evergreen forest, 8°13.513'N, 99°48.252'E, 435 m, 11–12.xi.2008: 1♀, Nan Province, Doi Phu Kha National Park, Office 6, 19°12.349'N, 101°4.617'E, 1360 m, 22–29.ix.2007; 1♂, 1♀, Office 4, 19°12.562'N, 101°4.93'E, 1374 m, 1–8.ix.2007: 1♂, 5♀, Chiang Mai Province, Queen Sirikit Botanic Garden, 18°53'67.5''N, 98°51'57.7''E, 700 m, 22–28.v.2007, 4–12.vi.2007: 1♂, Kamphaeng Phet Province, Mae Wong National Park, Chong Yen, 16°5.212'N, 99°6.576'E, 1306 m, 17–24.ix.2007 (QSBG and NMWC).
Etymology. The species is named from the Thai thao sa-eo (with arms set akimbo) in fanciful reference to the two widely spaced apical processes of the left surstylus.
Diagnosis. A species with antennal stylus bare and legs black except for the mid and hind tibiae and with front tibia blackish yellow with a paler base. Distinct ventral bristles are present near the base of both the front and mid metatarsi. Mid tibia near middle with a very long bristle dorsally and another ventrally just beyond it.
Description. Male: body length 3.2–4.5 mm. Head subshining black, dusted greyish; face black, yellowish below; postocular occipital setae black to brownish, some pale bristles on lower occiput. Antenna greyish black; postpedicel slightly paler, ovate in lateral view, ~2.0–2.5X long as wide, lacking dorsal seta; stylus bare, ~5–6X long as postpedicel, apical 0.2 narrower, whitish in some lights. Mouthparts blackish, palpus very narrow, with 2 distinct fine bristles apically. Thorax with ground colour black, subshining with vaguely bluish reflections; pleurae paler, dark yellowish black; yellowish on postalar callus, scutellum narrowly at base and postpronotal lobe very narrowly on outer edge; scutum subshining, thinly and uniformly covered with greyish dust, more strongly dusted on prescutellar area and pleura; acr 2–4-serial, fine and hair-like; dc uniserial, similar to acr but posterior dc and acr before prescutellar area strong; 2 almost equally long npl, 1 strong pa and 2 apical sct with several fine, pale, marginal hairs. Legs with coxae and femora black; T 2 yellow; T 3 yellow, somewhat darker on distal 0.3–0.6; T 1 yellowish black, rather paler basally; mid and posterior tarsi clear yellow, becoming darker on distal segments; anterior tarsi rather darker than other legs. Coxae with hairs and bristles whitish. F 1 with ventral fringe of pale hairs very fine, inconspicuous, shorter than limb is deep. F 2 very slightly concave about middle viewed from above; a few fine setae anteriorly near base and ~2–3 short dark bristles anterodorsally near tip, otherwise short-haired. F 3 moderately inflated, widest 0.6–0.8 from base were ~2X wide as at base; ventral spines comprising av row of 7–9 strong bristles as long as limb is deep behind which are 11–12 somewhat shorter bristles; pv fringe with 2–3 strong black bristles on distal 0.3, continued basally by shorter yellowish hairs; with ~5 strong black curved slightly proclinate bristles anteriorly on distal 0.5. T 1 with 1 distinct fine bristle dorsally at 0.7 from base and a few smaller outstanding setae posteriorly on distal 0.3; apical circlet weakly developed except 1 dorsal seta ~0.4X long as MT 1. T 2 with 1 long somewhat proclinate bristle 0.7 X long as limb dorsally at 0.3–0.4 and 1 bristle ventrally at 0.5 from base; apical circlet of ~7 strong setae, including 2 ventrally and anteroventrally 0.5 and 0.7X long as MT 2. T 3 slightly swollen distally, strong bristles dorsally at 0.5 and 0.6 and anteriorly at 0.8–0.9; apical circlet with only 1 dorsal and 1 av strongly developed. Anterior and mid tarsi with pair of fine but distinct dorsal hairs apically on segments 1 and 2; MT 1 and MT 2 with strong ventral bristle at base; MT 3 with 3 short spines ventrally. Wing membrane distinctly brownish, veins brown; stigma faint, reaching costa 0.6–0.7 distance between end of R 1 and R 2+3. Squamae with pale fringes. Halter white, with darker stem. Abdomen brownish black with somewhat bronze reflections, strongly dusted; setae whitish or slightly yellowish brown, longest laterally on posterior margins of tergites 1–3. Terminalia (Figs 187–191) black, epandrial lamellae with fine apical bristles (Fig. 187). Right epandrial lamella with short pointed apical process. Left surstylus (Figs 187, 191) bilobed; upper (dorsal) lobe broad with blunt tip; lower lobe narrower. Right surstylus (Figs 189, 190) elongate, curving ventrally and inwardly. Hypandrium (Fig. 188) with short subapical spine and several irregularly shaped, yellowish black subapical processes originating from inner face. Female: Differing from male as follows. T 1 and T 2 with dorsal setae less strongly developed; T 3 lacking distinct anterior bristle at 0.8–0.9 from base. F 3 less strongly inflated, only ~1.5X deep as at base; number of ventral spines variable but less numerous (only ~ 11–19 in total); pv fringe fine and hairlike throughout, with at most only 1 black bristle apically; only 1 strong, black, curved, slightly proclinate bristle anteriorly at 0.8–0.9. Abdomen somewhat paler, brownish, with all setae shorter. Terminalia (Figs 192, 193) with tergite 8 black, strongly sclerotized, encircling abdomen, almost completely divided dorsally. Sternite 8 white, rather irregularly protuberant (Fig. 192), very weakly sclerotized, membranous, ventrally with pair of ill defined membranous tubercles; left tubercle only with very small black patch of more strongly sclerotized tissue (sometimes divided into 2 parts) apically. Sternite 10 small, pilose.
Comments. Hybos thaosaeo sp. nov. is very similar to H. kaluang sp. nov. and the differences between them are discussed in the account of that species. Hybos thaosaeo sp. nov. is widely distributed in Thailand (Fig. 277) in low to mid elevation forests from 453–1,374 m. It has been recorded from the Luang Prabang, Thanon Thongchai, Tenasserim and Nakhon Si Thammarat ranges. Locality data suggest a preference for dry evergreen and perhaps also lower elevation zones of hill evergreen forest. Adults are most numerous during the wet season between May and September but have been found in all months of the year except February and March at the height of the dry season. The asymmetric apical sclerotization of only the left of the paired membranous tubercles on sternite 8 of the female is remarkable. The strength and pattern of sclerotization varies somewhat but is consistently present and asymmetrical although its function remains unknown.
description: Published as part of PLANT, ADRIAN R., 2013, The genus Hybos Meigen (Diptera: Empidoidea: Hybotidae) in Thailand, pp. 1-98 in Zootaxa 3690 (1) on pages 72-74, DOI: 10.11646/zootaxa.3690.1.1, http://zenodo.org/record/6329811