Orthobrachia hirowatarii Huang, Su & Stuening

Huang, Guo-Hua, Su, Zi-You & Stuening, Dieter, 2016, Taxonomic notes on the genus Orthobrachia Warren, with description of a new species from China and Thailand (Lepidoptera, Geometridae), ZooKeys 609, pp. 121-137 : 132-133

Taxon classification Animalia Lepidoptera Geometridae

Orthobrachia hirowatarii Huang, Su & Stuening sp. n. Figures 3 G–H, 4G, 5G

Diagnosis.

This new species is externally very similar to Orthobrachia maoershanensis but can be distinguished by the dark-brown ante- and postmedial lines, which are stronger and straight in hirowatarii , more delicate and the postmedial line curved inwards near costa in maoershanensis . The tornal dark brown patch is broader and shorter in the latter, reaching up to the middle of the medial band; the narrower patch of hirowatarii is longer and reaches almost back to the antemedial line. In the hind wing, the narrow, almost black postmedial line is almost straight between apex and tornus in hirowatarii , while it is evenly curved between anterior and posterior margin distinctly basad of apex and tornus in maoershanensis . The valve in the male genitalia is longer and narrower with two processes near the base in hirowatarii , a multi-dentate costal process and an arm-shaped, angled, apically densely setose saccular process. The costal process in maoershanensis is short and apically rounded, the saccular process thumb-like, with shorter setae at tip. In addition, the latter has a broad, basal costal process, similar to that found in flavidior . The aedeagus is short, stout, with two cornuti in maoershanensis , while hirowatarii has a longer, narrow aedeagus with a bunch of external spines at the border between shaft and vesica. The female genitalia are also clearly separable, though both (and simpliciata , too) have a similar, asymmetric, stellate signum (very small in simpliciata ). Hirowatarii has a large, rather quadrate, strongly sclerotized antrum, with a transverse, semicircular, broad lamella antevaginalis distally, decorated with a pair of lateral spines. In maoershanensis , the quadrate part is absent, the semicircular part more delicate and the spines smaller. Moreover, maoershanensis has a much longer, fluted ductus bursae and the bursa is smaller (in our Fig. 5G with a damage on the left side).

Description.

♂ Expanse 27-30 mm, length of forewing 13-15 mm.

Head. Antenna bipectinate to three-fourths, rami arising from the proximal one third of flagellomers, apical 15-16 segments not pectinated. Frons narrow, smooth-scaled, lower half with yellow, upper half with greyish-brown scales. Vertex with larger, creamy white scales. Palps narrow, short, scaled light greyish-brown. Thorax. Patagia greyish-brown, tegulae creamy white, thorax subdorsally with two longitudinal, dark brown lines (which are continued on the abdomen). Forewing ground colour creamy white, with transverse striation of dark brown and orange, scales of the same colours also accompany the veins. There is a dark brown patch at tornus, extended along posterior margin, reaching almost the antemedial line. The latter line strong, dark brown, straight, shortly curved basad and broadening near costa; postmedial line straight from tornus to 1/4 of costal margin; there is a small, semicircular loop between veins R5 and M1 at termen (also present in maoershanensis and simpliciata ); cilia dark brown at posterior half of termen, creamy white between the dark end of the veins in anterior half. Hindwing rounded; ground colour similar to forewing, with broad, greyish-brown medial area. Thin blackish-brown postmedial line straight between tornus and apex, discal cell with a small black spot. Cilia brown, apart from those in the spaces M1-M3, M3-CuA1 and CuA1- CuA2 which are creamy white.

♀ Expanse 30-34 mm, length of forewing 14-16 mm, antenna filiform. The ground colour of the wings and the pattern elements are very similar to the male.

Male genitalia: Uncus rather broad and short, beak-shaped. Gnathos consisting of weak, flattened lateral arms only, not fused in the middle. Valva long and narrow, with the distal end of costa projecting above the valve surface. Costa with a large, multi-dentate process just basally of the middle, and saccular process with a narrow basal arm and a broader, globular, apically densely setose distal parts. Juxta a large, broad, somewhat elongated plate. Saccus broad and rounded, flattened at base. Aedeagus slender with a bunch of well-developed cornuti, arising externally at the border between shaft and vesical, the latter without cornuti.

Female genitalia: Papillae anales elongate, apophyses long; a. anteriores about 3/5 the length of a. posteriores; lamella antevaginalis well sclerotized, semicircular, with a pair of spines bilaterally, united with a large, nearly quadrate, well sclerotized antrum; bursa copulatrix thinly membranous, pear-shaped (not clearly visible in our figure), distal part sclerotized, fluted, containing a wrinkled band; ductus bursae very short; signum rounded, margins and internal surface covered with spines.

Holotype.

♂, China: Sichuan, Yingjing County, Longcanggou Town, 1420 m, 10.VIII.2015, light trap, G.H. Huang leg., Gen. prep. no. HGH-HUNAU_0165 deposited in HUNAU.

Paratypes.

5♂♂8♀♀, same locality as holotype, but 09-11.VIII.2015, G.H. Huang, T. Hirowatari, T.T. Yu and M. Wang leg., Gen. prep. no. HGH-HUNAU_0168 (female), deposited in HUNAU and SCAU. 1♂, N.Thailand, Changwat Chiang Mai, 23 km NW Sop Kha, 1 km E Kop Dong, 1650 m, 29.I.2000, leg. Márton Hreblay. Gen. prep. no. 2304-DS, ZFMK

Etymology.

The specific epithet is in honour of Prof. Toshiya Hirowatari, who was the supervisor of the first author for Ph.D. Course in Osaka Prefecture University.

Biology.

The adults fly in August in Sichuan, in January in Thailand, at elevations between 1400 and 1700 m. The host of larvae is unknown.

Distribution.

China (Sichuan), Thailand.

Remarks.

This new species was collected at a small village in the forest, with a light-trap inside a house, with artificial vegetation around it. Therefore the habitat seems to be quite different from that of other Orthobrachia species. E. g., Orthobrachia maoershanensis originates from environment with natural vegetation in the core zone of the Nature Reserve.