Terrobittacus emeishanicus, He & Hua, 2023

He, Le-Le & Hua, Bao-Zhen, 2023, Two new species of the genus Terrobittacus Tan & Hua, 2009 (Mecoptera, Bittacidae), ZooKeys 1148, pp. 29-39 : 29

Terrobittacus emeishanicus sp. nov.

Figs 1 , 2

Type material.

Holotype: ♂; China, Sichuan Province, Emeishan; 29°35'10"N, 103°11'19"E; alt. 1320 m; 28 July 2021; leg. Lu Liu, Jia-Yi Ren and Jie Zhang. Paratypes: 3♂11♀, same data as for the holotype.

Diagnosis.

The new species can be readily recognized from its congeners by the following characters: 1) wing with numerous markings and a reddish brown pterostigma; 2) femora and tibiae apices, and hind legs tarsi reddish brown; 3) male epandrial appendages tapering toward apex; 4) male cerci clavate, slightly expanded distally; 5) gonocoxites with one to three pairs of long brown distal bristles; and 6) basal half of female subgenital plate fused, with a black, strongly sclerotized V-shaped carina along midventral line, distal half cleft.

Description.

Measurements (N = 15): AL = 7.62 ± 0.49 mm; BL = 15.66 ± 1.00 mm; FL = 22.26 ± 0.53 mm, FW = 5.08 ± 0.21 mm; HL = 19.55 ± 0.50 mm, HW = 4.69 ± 0.23 mm.

Head (Fig. 1C ) Vertex and frons yellowish brown; ocellar triangle black, lateral ocelli twice as large as median ocellus; clypeus and labrum yellowish to blackish brown, lateral sides darker; maxillary palp yellowish brown, 3rd segment longer than 4th and 5th segments combined. Antennae yellowish brown; scape cylindrical; pedicel spherical; flagellum filiform and ciliated, with distinct segments basally and obscure beyond 13th segment.

Thorax (Fig. 1D ) Nota unevenly blackish brown; mesonotum prominence darker, each with one black seta; meso- and metanotum with light median streak, bearing one or two setae on posterior margins. Pleura, coxae and mera light brown. Legs yellowish brown; femora and tibiae apices, and hind leg tarsi reddish brown (Fig. 1B ); hind basitarsus as long as tarsomeres II-IV together; one or two black spines along each side of proximal tarsomere IV (Fig. 1E ).

Wings (Fig. 1A ) Forewing membrane hyaline with yellowish tinge; pterostigma reddish brown; grayish brown clouding flecks at OM, ORs, FRs, FR4+5, CuP ending, and most cross-veins; Pcv one. FRs near FM; Sc ending slightly beyond level of FR4+5; Scv beyond FRs; CuP ending posteriorly curved, and near FM3+4; Cuv before level of FM; 1A ending before FM; 2A ending near OM; Av absent. Hindwing similar to forewing in general pattern and coloration, but Sc ending and Scv before level of FRs.

Abdomen of male (Fig. 2D-H ) Terga II-VIII yellowish brown, gradually darker, each with a black antecosta; tergum VIII emarginate in V-shaped on posterior margin. Epandrial appendages yellowish brown, equal or shorter than half length of gonocoxites, quadrangular in lateral aspect, with long yellow hairs along margins; basal portion broad, tapering toward apex (Fig. 2H ); bearing sparse long yellow hairs and nine to eleven stout black apical spines on inner surface. Dorsal part of tergum X greatly vestigial, ventral plate yellowish to reddish brown, extending from cercus to base of proctiger. Upper branch of proctiger sickle-like, posteriorly curved; anterior central edge slightly constricted; bearing two small hairy denticulate processes basally; lower branch of proctiger short, tapering toward apex (Fig. 2G ). Cerci clavate, slightly expanded at distal, shorter than gonocoxites. Gonocoxites yellowish brown, with one to three pairs of prominently long brown distal bristles. Gonostylus short, irregular-shaped, and bearing numerous brown setae. Basal aedeagal lobes broad, distal portions slender and acute; penisfilum greatly coiled.

Abdomen of female (Fig. 2A-C ) Terga II-IX yellowish brown, each with a black antecosta. Subgenital plate sclerotized, yellowish brown; basal half fused, with a black, strongly sclerotized V-shaped carina along midventral line; distal half bearing numerous brown setae and divided mesially by membrane. Tergum IX slightly truncated distally. Tergum X extending ventrad and beyond base of cerci. Supraanal plate tapering toward apex; subanal plate broad, almost truncated apically, shorter than supraanal plate. Cerci slender, longer than anal plates.

Etymology.

The specific epithet refers to the type locality, Emeishan.

Distribution.

China (Sichuan Province).

Remarks.

As far as we know, Terrobittacus emeishanicus sp. nov. is probably the largest species of the genus, at least in terms of wingspan. The new species is similar to T. longisetus Tan & Hua, 2009 in body color and male genitalia, but can be differentiated from the latter by following features: numerous prominent markings on the wing (cf. no prominent markings); male epandrial appendages tapering toward the apex (cf. male epandrial appendages broad); male cerci slightly expanded distally (cf. thickening toward apex); and a V-shaped carina along the midventral line of the female subgenital plate (cf. X-shaped).

Figures

Figure 1. Terrobittacus emeishanicus sp. nov. A right wings of male B male habitus in lateral view C head in frontal view D thorax in dorsal view E tarsomeres IV, V and claw of left foreleg. Abbreviations: see Materials and methods. Scale bars: 2.0 mm (A); 5.0 mm (B); 0.5 mm (C, D); 0.2 mm (E).

Figure 2. Terrobittacus emeishanicus sp. nov. A female terminalia in lateral view B female terminalia in ventral view C female terminalia in dorsal view D male terminalia in lateral view E male terminalia in dorsal view F male terminalia in posterior view G abdominal segment X and proctiger in lateral view H epandrial appendages in ventral view. Abbreviations: see Materials and methods. Scale bars: 0.5 mm (A, B); 0.2 mm (C-H).