Bittacus diaoluoshanus Chen & Hua

Chen, Jing & Hua, Baozhen, 2011, A second species of Bittacus Latreille, 1805 (Mecoptera: Bittacidae) from Hainan Island, China, Zootaxa 3093, pp. 64-68 : 64-68

publication ID	https://doi.org/ 10.5281/zenodo.205915
DOI	https://doi.org/10.5281/zenodo.6193813
persistent identifier	https://treatment.plazi.org/id/03A66A1D-FFF0-FFC6-FF08-9C00FAD2C64C
treatment provided by	Plazi
scientific name	Bittacus diaoluoshanus Chen & Hua
status	sp. nov.

Treatment

Bittacus diaoluoshanus Chen & Hua , sp. nov.

( Figs 1–4 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 )

Holotype: 3, China: Hainan Island, Diaoluoshan (alt. 910 m), 26 May 2008, coll. Qiang Fu, deposited in NWAU. Paratypes: 13ƤƤ113, same data as holotype, deposited in NWAU.

Etymology. The new species is named after its type locality, Diaoluoshan. Description. Body 15.7–16.3 mm long; forewings 19.7–20.2 mm long, 4.2–4.4 mm wide; hindwings 17.7– 18.9 mm long, 3.7–4.0 mm wide ( Fig. 1 View FIGURE 1 A).

On head, vertex, frons and maxillary palps yellowish brown; labrum and labial palps dark brown. Fifth maxillary palpomere shorter than fourth. Labrum acutely triangular, dark brown. Compound eyes well-developed, ovoid in shape. Ocellar triangle black ( Fig. 4 View FIGURE 4 A). Antennae filiform, 7.0 mm long; basal scape and pedicel stout, almost equal in size; flagellum 20-segmented, flagellomeres ciliated and tapering distally ( Fig. 1 View FIGURE 1 B–D).

Pronotum yellowish brown, with two long setae on anterior and posterior margins, respectively; anterior half of mesonotum unevenly blackish brown laterally, and yellowish brown mesally; remaining part of mesonotum and metanotum light yellowish brown. Pleura and legs yellowish brown; posterior margin of each coxal cavity with a black streak; several thick black setae on femora and tibiae; length ratio of the two apical tibial spurs as 1:1.4; fourth tarsomere with two spines on each side; total length of second and third tarsomeres shorter than basitarsus. Wing membrane light yellowish brown ( Fig. 1 View FIGURE 1 A). Pterostigma prominent; two pterostigmal crossveins (Pcv); four distinct tawny brown spots, one each at the origin of radial sector (ORs), the first fork of radial sector (FRs), the origin of media (OM), and the distal end of CuP; one distinct tawny stripe along the apical margin extending from pterostigma to beyond the apex; two nygmata each in cells R4+5 and 1R5, respectively. Sc ending beyond FRs; cubital crossvein (Cuv) and vein 1A ending at the fork of media (FM). Prominent hyaline thyridium at FM. In a few specimens a crossvein between veins R2 and R3; four crossveins blackish brown, with slight cloudiness at first radial (1r), first radio-medial (1r-m), medial (m), and medio-cubital crossveins (m-cu); anal crossvein (Av) lacking. Hindwings similar to forewings except for vein Sc terminating slightly before FRs. One distinct, long, black seta at base of the costal margin of fore- and hindwings.

Male abdomen with terga yellowish brown; terga III–VI each with a narrow black transverse antecosta; posterior margin of tergum VIII deeply emarginate distally in a V-shape ( Fig. 2 View FIGURE 2 B). Sterna darkening gradually from light yellow to yellowish brown. Tergum IX modified into a pair of epandrial appendages, which are subquadrangular at lateral aspect, and slightly emarginate on distal margin; ventral margin of the epandrial appendages and lower half of the distal margin thickening on inner side; some sparse, long, black spines on the upper corner of the distal margin, and some short, stout spines densely on the lower corner ( Figs 2 View FIGURE 2 B, C, 3B); left and right epandrial lobes connected by a membranous area basally, and divergent distally ( Fig. 3 View FIGURE 3 B). Upper branch of proctiger digitate and bearing a bundle of long brown setae distally, protruding from between epandrial appendages; the lower branch about half as long as the upper branch, tapering towards apex and sparsely furnished with short setae ( Fig. 3 View FIGURE 3 A). Tergum X saddle-like, extending caudoventrally around base of cercus into a narrow sclerite. Cerci slightly clavate ( Fig. 3 View FIGURE 3 B), corresponding to half length of the epandrial appendage ( Fig. 2 View FIGURE 2 B). Gonocoxite longer than epandrial appendages, separated posteroventrally by a V-shaped unsclerotized median area ( Fig. 2 View FIGURE 2 C). Gonostylus short and blunt distally with a process on inner side, and clothed with a tuft of long setae. Aedeagus narrow basally, expanded subbasally into two broad lateral aedeagal lobes, then gradually tapering into a very long and coiled penisfilum ( Fig. 2 View FIGURE 2 B, C).

Female abdomen similar to that of male in coloration. Each tergum with a black antecosta; terga VII and VIII the longest and broadest. Subgenital plate strongly sclerotized, separated medially by a broad triangular membranous area into two halves ( Fig. 4 View FIGURE 4 B), and with two bundles of black setae at the posterior end ( Fig. 4 View FIGURE 4 B) and a dropshaped membranous concavity midway along the lateral margin ( Fig. 4 View FIGURE 4 C); anterior portion brownish black, fading gradually from anterior to posterior portion. Tergum X slightly emarginate posteriorly ( Fig. 4 View FIGURE 4 D), and not extending ventrally ( Fig. 4 View FIGURE 4 B). Supraanal plate shorter than subanal plate; supra- and subanal plates truncated apically ( Fig. 4 View FIGURE 4 B, D). Cerci slightly longer than the subanal plate.

Distribution. China (Hainan Island).

Diagnosis. Bittacus diaoluoshanus sp. nov. is distinguished from other species of the genus Bittacus by two crossveins below pterostigma; four tawny brown spots each at ORs, FRs, OM, and the distal end of CuP; one apical band from pterostigma to beyond apex; absence of Av; and male epandrial appendages subquadrangular at lateral aspect. The new hangingfly resembles B. trapezoideus Huang & Hua, 2005 from Gansu and Shaanxi Provinces, China in the shape of the epandrial appendages of male genitalia, but the species differ in wing pattern (the wings of B. diaoluoshanus sp. nov. have only four small cloudy spots and one apical band, but those of B. trapezoideus are diffused with cloudy spots along crossveins).

B. diaoluoshanus sp. nov. differs from B. hainanicus Tan & Hua, 2008 from Bawangling and Wuzhishan on Hainan Island by wing pattern ( B. diaoluoshanus sp. nov. possesses a blackish apical band on wings, B. hainanicus lacks the apical band but has a noticeable cuneiform cloudiness along R5 on wings), and by epandrial lobes of the male genitalia (those of the former are subquadrangular, but those of the latter are extremely complicated and divided into two parts, irregular).

The apical band on wings also occurs in B. monastyrskiyi Bicha, 2007 from Vietnam, but the absence of Av and band along vein R5, and subquadrangular epandrial appendages can distinguish B. diaoluoshanus sp. nov..

Remarks. Somma (2009) cited a personal communication from Wes Bicha that B. hainanicus might conceivably be a junior synonym of B. monastyrskiyi . Although the two hangingfly species have some similarities in wing pattern, they differ greatly in male genitalia; thus, it is very unlikely they are conspecific. In B. hainanicus the wings lack Av and an apical band, and epandrial appendages consist of a subtriangular lobe and a complicated prolongation, while in B. monastyrskiyi the wings have one Av and a dark brown band along R5, and the epandrial appendages are made up of a truncated dorsal lobe caudally and a prolonged ventral lobe ( Bicha 2007).