Euhybus basiflavus sp. nov., 2024

Li, Meilin, Wang, Jingyu & Yang, Ding, 2024, The genus Euhybus Coquillett (Diptera: Hybotinae) from China, with descriptions of five new species, Zootaxa 5481 (5), pp. 520-530 : 521-522

1. Euhybus basiflavus sp. nov.

( Fig. 1 )

Diagnosis. Fore and mid femora black with brownish yellow tips, hind femur entirely black. Mid tibia dark yellow. All tarsomeres 1–2 yellow. Hypandrium with a long acute median process.

Description. Male ( Fig. 1a ). Body length 3.3 mm, wing length 3.4 mm.

Head black with pale gray pollinosity. Eyes dark yellow with weakly enlarged upper facets. Setae and setulae on head black; ocellar tubercle weak, with 2 long anterior oc and 2 short posterior setulae. Antenna blackish; first flagellomere slightly longer than scape + pedicel, 2.5 times longer than wide, without dorsal setae; arista 4.2 times as long as first flagellomere, dark brown, bare, with apical 1/4 thin. Proboscis brownish, distinctly shorter than head, thickened, nearly obtuse apically; palpus dark brown with 1 long, curved seta at extreme tip.

Thorax black with pale gray pollinosity except mesoscutum shiny with wide posterior portion pollinose. Setae and setulae on thorax black; h absent, 2 long strong npl, setula-like acr biseriate, setula-like dc uniseriate except only 1 posterior most dc slightly long, 1 long thin psa; scutellum with 6 marginal setulae and 2 long strong sc. Legs black except tips of fore and mid femora dark brownish yellow, tip of fore tibia and entire mid tibia bright yellow; all tarsi yellow with tarsomeres 3–5 blackish. Setae and setulae on legs black. Fore femur nearly as thick as mid femur; hind femur 2.4 times as thick as mid femur, with 2–3 long, thin preapical ad. Hind femur with row of mostly long av spines, basal portion with about 3 rows of ventral spines. Fore tibia thickened, apically with 3 thin setae (1 posterior seta longer than others); mid tibia with 2 long, strong ad, apically with 4 thin setae (of which 1 pv is relatively thick, very long, nearly as long as mid tarsomere 1). Hind tibia without dorsal setae, apically with 1 short, thick av, 1 long, thin preapical dorsal seta and 1 long, strong pd. Fore and mid tarsomere 1 with some long setulae, apically with 1 long, thin ad and 1 long, thin pd; mid tarsomere 1 with 1 long, strong pv at base. Hind tarsomere 1 with 1 strong ventral seta at base, apically with 1 strong av. Wing lightly infuscate; costal vein with thin longer setae on basal 2/3; dark brown pterostigma short and rounded (about 1/6 as long as cell r 1, not filling apex of cell r 1); veins dark brown. Squama brown with brown setulae. Halter dark brown.

Abdomen shiny black with thin gray pollinosity, sternites 1–3 weakly sclerotized; hypopygium distinctly swollen, broader than abdomen. Blackish setae and setulae on abdomen, except dark yellow basally. Male genitalia: Lepn slightly narrower than repn, with inner margin slightly incised ( Fig. 1b ); lsur very wide, apically irregularly bifurcated in lateral view ( Fig. 1d ). Repn with weakly incised inner margin; rsur rather wide, irregularly furcated, with one long, thin right process and one wide left process bearing row of long bristles in lateral view ( Fig. 1c ). Hypandrium distinctly 1.9 times longer than wide, apically with three processes; median process is longest and acute; left process very short and acute; right process short, finger-like ( Fig. 1g ).

Female. Unknown.

Type material. HOLOTYPE ♂, China: Xizang, Bomi, Palong [31°36'39.57"N, 95°21'58.44"E, 3110 m], 2013.IX.9, Gang Yao ( CAU).

Distribution. China (Xizang).

Remarks. The new species is similar to E. longiseta from Xizang, but may be separated from the latter by hind tarsomeres 1–2 yellow and hypandrium with a long acute median process. In E. longiseta , the hind tarsus is entirely black, and the hypandrium has the weakly incised apical margin without median process ( Wang et al. 2013).

Etymology. The specific name refers to the yellow base of the tarsi.

Figures

FIGURE 1. Euhybus basiflavus. a. Male habitus, lateral view; b. Genitalia, dorsal view; c. Right surstylus, lateral view; d. Left surstylus, lateral view; e. Right surstylus, dorsal view; f. Left surstylus, dorsal view; g. Hypandrium, ventral view. Scale bar: 0.5 mm (a); 0.1 mm (b–g). Abbreviations: lepn = left epandrial lamella; lsur = left surstylus; repn = right epandrial lamella; rsur = right surstylus.