Bittacus longilobus, Zhang & Du & Hua, 2020

Zhang, Yan-Na, Du, Wei & Hua, Bao-Zhen, 2020, Three new species of the genus Bittacus Latreille, 1805 (Mecoptera: Bittacidae), with a key to the species of Bittacidae in South China, Zootaxa 4718 (3), pp. 381-390 : 386-389

Bittacus longilobus sp. n.

( Figs. 6–7 )

Type material. Holotype. ♂, CHINA: Guangdong, Meizhou, Mt. Yim Na (24°24′11″N, 116°24′28″E, elev. 700 m), 16 May 2018, Ji-Shen Wang leg. Paratypes. 5♂, 5♀, same data as for the holotype .

Diagnosis. The new species can be distinguished from its congeners by the following characters: 1) three cross- veins arranged in a brown line at FM 3+4 ( Fig. 6D ); and 2) epandrial lobe trapezoid for the main body in lateral view, with a slender elongate lobe at ventro-distal apex and a blunt process at dorso-distal apex; the lobe roughly one-third as wide as and twice as long as the main epandrial lobe ( Fig. 7A ).

Etymology. The specific epithet “ longilobus ” is derived from the Latin “ longus ” (long) and “ lobus ” (a lobe), referring to the long ventro-distal lobe of the male epandrium.

Description. Head ( Fig. 6E ). Vertex yellowish brown. Ocellar triangle blackish brown. Rostrum slightly yellowish basally, brown medially and yellowish brown apically; labial and maxillary palps dark brown. Antenna filiform; scape and pedicel pale brown; flagellum blackish brown, 17-segmented.

Thorax ( Fig. 6B, C, F ). Pronotum yellowish brown, with two long setae on anterior and posterior margins. Mesonotum fuscous laterally, with a pair of black setae, scutellum light yellowish; metanotum yellowish brown laterally, light yellowish medially, scutellum pale yellowish. Legs yellowish, fuscous at apex; several short black setae on femora, tibiae and tarsi; tibia with two apical spurs, the longer one about twice as long as the shorter one in hind leg. Tarsomere IV bearing 27–31 prominent black ventral teeth and 3–4 setae on each side subbasally; tarsomere V with 30–33 ventral teeth.

Wings ( Fig. 6D ). Wing membrane yellowish-brown. Forewing length 19.9–21.7 mm, width 4.3–5.2 mm; pterostigma prominent; six markings, one each at OM, ORs, Scv, FRs and ends of CuA and CuP; crossveins and apical margin shaded with dark brown; thyridium conspicuous with pale border at FM; 1A terminating beyond FM; one Scv; two Pcv; no Av. Hindwing length 17.9–19.2 mm, width 4.0– 4.7 mm, similar to forewing.

Abdomen of male ( Figs. 6A , 7 A–B). Terga II–VIII yellowish brown, each with a narrow black antecosta. Epandrial lobe yellowish, trapezoid for the main body in lateral view, with a slender elongate lobe at ventro-distal apex; the lobe roughly one-third as wide as and twice as long as the main epandrial lobe; a patch of short black thick spines on the inner surface at the dorso-distal portion of the main epandrial lobe and the subapex of the distal lobe, respectively; the distal lobe convergent distally in dorsal view. Upper branch of proctiger protruding between bases of epandrial lobe, furnished apically with long black hairs; lower branch of proctiger very short. Tergum X yellowish brown. Cerci elongate, slightly shorter than gonocoxites, but longer than the distal epandrial lobe. Gonocoxites yellowish brown, shorter than epandrial lobe; gonostylus reduced.Aedeagus expanded basally; penisfilum short and coiled approximately in apical half.

Abdomen of female ( Fig. 7 C–D). Terga II–VIII yellowish brown, each with a narrow black antecosta. Subgenital plate broad with a distal patch of stiff setae; yellowish brown, sclerotized and separated by a triangular median membranous area, and with an inconspicuous U-shaped distal membranous area in lateral view. Tergum X blackish brown, only slightly extending ventrally. Supraanal plate shorter than subanal plate, truncate apically. Cerci slightly shorter than subanal plate.

Distribution. China (Guangdong).

Remarks. Bittacus longilobus sp. n. resembles B. flavidus Hua & Huang, 2005 in general appearance, but can be readily separated from the latter by the following characters: 1) wing without fleck along R 5 distally (cf. wing with a quadrate brown fleck along R 5 distally); 2) tergum X blackish brown, only slightly extending ventrally (cf. tergum X prominently extending ventrally); and 3) epandrial lobes convergent, trapezoid for the main body in lateral view, with a slender elongate lobe roughly twice as long (cf. epandrial lobes divergent, the main body trapezoid, with a slightly elongate lobe one-half as long).

Bittacus longilobus sp. n. was collected from the same locality (Mt. Yim Na) as B. gressitti , but differs from the latter in male genitalia: 1) the epandrial lobe long and thin, with a slender elongate lobe roughly one-third as long as wide (cf. the main body of the epandrial lobe short and thick, with a produced lobe one-fourth as long as wide); and 2) upper branch of proctiger long, apex rounded, furnished apically with long hairs (cf. upper branch of proctiger curved upward, apex truncated, with a prominent side lobe).

Figures

FIGURE 6. Bittacus longilobus sp. n. A. Male habitus in lateral view, paratype; B. articulation of basitarsus and tibia, to show the two apical tibial spurs, holotype; C. tarsomeres IV–V, paratype; D. right wings, holotype; E. head in frontal view, holotype; F. thorax in dorsal view, paratype. Abbreviations: see Fig. 2 caption. Scale bars: A = 5 mm; B, E and F = 0.5 mm; C = 0.2 mm; D = 2 mm.

FIGURE 7. Bittacus longilobus sp. n. A. Male terminalia in lateral view, holotype; B. male terminalia in dorsal view, holotype; C. female terminalia in lateral view, paratype; D. female terminalia in ventral view, paratype. Abbreviations: see Fig. 3 caption. Scale bars = 0.2 mm.