Bittacus dilobus, Hua, 2022

Le-Le, HE & Bao-Zhen, HUA, 2022, A review of Bittacidae (Mecoptera) in Guizhou, China with descriptions of three new species, European Journal of Taxonomy 839, pp. 103-119 : 107-110

Bittacus dilobus sp. nov.

urn:lsid:zoobank.org:act:141D3F0D-62D0-4250-870D-6BB70C8C6AC5

Figs 2–4

Diagnosis

The new species is unique in having the male gonocoxites with two triangular caudal lobes, elongated aedeagal lobes with distal half broadened into an acute distal process and a greatly elongated and coiled penisfilum.

Etymology

The specific epithet is derived from the Greek ʻdi-ʼ (two, double) and ʻlob-ʼ (a lobe), referring to the male gonocoxites with a pair of triangular lobes.

Type material

Holotype CHINA • ♂; Guizhou Province, Leishan County, Leigongshan ; 26°22′12″ N, 108°7′48″ E; 1440–1500 m a.s.l.; 15 Jul. 2021; Le-Le He leg.; NWAU.

Paratypes CHINA • 3 ♀♀; same collection data as for the holotype; NWAU .

Description

MEASUREMENTS. AL 7.4–8.1 mm, BL 16.1–19.6 mm, FL 22.4–22.7 mm, FW 5.1–5.5 mm, HL 19.0– 19.4 mm, HW 4.4–4.7 mm.

HEAD ( Fig. 2B ). Vertex yellowish brown; frons grayish brown; ocellar triangle black, median ocellus smaller than lateral ocelli; clypeus and labrum yellowish to blackish brown, lateral sides darker; maxillary palp blackish brown except distal segment yellowish brown. Antennae yellowish brown; flagellum ciliated, with distinct segments basally and obscure beyond 16 th segment.

THORAX ( Fig. 2C ). Pronotum unevenly blackish brown, with setae along anterior margin; mesonotum blackish brown in anterior two-thirds; remaining parts and metanotum yellowish brown, with light brown median streak; two setae along posterior margins of meso- and metanotum respectively. Pleura pale yellowish brown. Legs unevenly yellowish brown; femora and tibiae with black apices ( Fig. 2A ); length ratio of two apical tibial spurs as 2:3 ( Fig. 2D ); hind basitarsus as long as tarsomeres II−IV together, each succeeding tarsomere shorter in turn; each side of basal tarsomere IV with one black seta ( Fig. 2E ).

WINGS ( Fig. 3 ). Forewing membrane hyaline with yellowish tinge; pterostigma brown; small blackish brown cloudings at OM, ORs and FRs; Pcv two. Sc ending beyond level of FRs; Scv before FM; CuP ending near FM 3+4; Cuv two; 1A ending near FM; 2A ending before OM; Av absent. Hindwing similar to forewing, but Sc ending before level of FRs and FM.

ABDOMEN OF MALE ( Fig. 4A–C ). Terga II–VIII yellowish brown, each with a black antecosta; tergum VIII slightly emarginate in V-shape on posterior margin. Epandrial appendages yellowish brown, longer than half length of gonocoxites, ventral margin almost straight, but dorsal margin sags and crests with long hairs; with two conspicuous protrusions on inner surface, one ear-like on ventro-distal process, the other small triangular-shape on dorsal process, both bearing black spines apically. Tergum X black, greatly vestigial. Proctiger stout basally, sclerotized dorsally and ventrally; upper branch of proctiger fingerlike, bearing a bunch of short yellow hairs apically; lower branch of proctiger curved caudoventrad and tapering caudally, but enlarged apically. Cerci slender, longer than half length of gonocoxites. Gonocoxites yellowish brown except ventral portion blackish-brown, with a pair of triangular caudal lobes divided by V-shaped emargination. Gonostylus yellowish brown, greatly shortened, with hairs apically. Aedeagal lobes elongated, with distal half broadened into acute distal process; penisfilum greatly elongated and coiled.

ABDOMEN OF FEMALE ( Fig. 4D–F ). Terga II–VI yellowish brown, terga VII–VIII dull blackish brown, each with a black antecosta. Subgenital plate sclerotized, yellowish to blackish brown, divided mesially by conspicuous membrane, bearing 12–15 black setae distally; membranous emargination indistinct. Tergum IX yellowish brown, truncated distally, with a black, obtusely triangular fleck basally in dorsal view. Tergum X extending ventrally and beyond base of cerci. Supraanal plate shorter than subanal plate, longer than cerci.

Distribution

Guizhou Province, China.

Remarks

The new species resembles B. triangularis Issiki, 1929 from Liaoning Province in appearance, but can be separated from the latter by the following traits: the lower branch of the proctiger expanded apically (cf. the lower branch of the proctiger tapering caudally); the gonocoxites unevenly colored, with two caudal lobes (cf. the caudal portion of the gonocoxites long and curved dorsally); and the aedeagal lobe enlarged apically (cf. the aedeagal lobe tapering toward the apex).

Figures

Fig. 2. Bittacus dilobus sp. nov., ♂, holotype (NWAU). A. Habitus in lateral view. B. Head in frontal view. C. Thorax in dorsal view. D. Tibia with two apical tibial spurs of left foreleg. E. Tarsomeres IV, V and claw of left foreleg. Abbreviations: see Material and methods. Scale bars: A = 5.0 mm; B–C, E = 0.5 mm; D = 1.0 mm.

Fig. 3. Right wings of Bittacus dilobus sp. nov., ♂, holotype (NWAU). Abbreviations: see Material and methods. Scale bar = 2.0 mm.

Fig. 4. Bittacus dilobus sp. nov. A–C. ♂, holotype (NWAU). A. Terminalia in lateral view. B. Terminalia in dorsal view. C. Terminalia in ventral view. D–E. ♀, paratype (NWAU). D. Terminalia in lateral view. E. Terminalia in dorsal view. F. Terminalia in ventral view. Abbreviations: see Material and methods. Scale bars: A–C = 0.5 mm; D–F = 0.2 mm.