Description of Striogyia simianshana sp. nov. (Lepidoptera, Limacodidae) from Chongqing in southwest China

The discovery of Striogyia simianshana sp. nov. (Lepidoptera: Limacodidae) resulted from a research project investigating the biodiversity of the Simian Mountain Nature Reserve in Chongqing, Southwest China. This new species is characterised by several distinct features, namely the black, broken postmedial line of the forewing and the long filiform antenna found in males. The shape of its valva, transtilla, juxta and phallus also distinguish it from other congeners. Furthermore, images of the adult habitus and male genitalia are compared with similar species S. obatera Wu, 2011 and S. acuta Wu, 2020, which further illustrate characteristics unique to S. simianshana. A distribution map and key for Chinese Striogyia species are provided.


Introduction
The genus Striogyia was erected by , with S. snelleni Holloway, 1986 as the type species. At the same time, Holloway transferred S. foliola (Snellen, 1900) to this genus, which was originally placed in the genus Heterogenea Knoch, 1783. Later, in 1990, Holloway described a third species S. spinosa from Sumatra, Indonesia (Piepers and Snellen 1900;. In recent years, Wu (2011Wu ( , 2020 described two additional species distributed in China: S. obatera (Guizhou) and S. acuta (Shaanxi). Currently, the genus consists of these five species ranging from Indonesia and Malaysia to China.
The genus is generally characterised by the adult male filiform antennae and the oblique postmedial line running almost from the apex to the posterior margin of the forewing. In the male genitalia, the uncus and gnathos are weak or absent. The transtilla is well developed and strongly sclerotised.
This study focuses on the description of a new species, S. simianshana sp. nov., found in Mt. Simian of Chongqing Municipality, China. Although so far only two male specimens have been collected, their appearance differs from other congeners, particularly in the male genitalia. Hence, in this study, we formally describe these specimens as a new species.

Material and methods
The specimens were collected at a 220V/450W mercury light and a DC black light in Mt. Simian. Wingspan was measured from forewing apex-apex and the forewing length from the wing base to the apex. Standard methods for dissection and preparation of the genitalia slides were used (described by Kononenko and Han 2007). The specimens were photographed using a Nikon D700 camera while the photographs of the genitalia slides were captured using an Olympus photo microscope aided by Helicon Focus software and then further processed using Adobe Photoshop CS6. The type material of the new species is deposited in the collection of the Northeast Forestry University (NEFU), Harbin, China.

Diagnosis.
The new species is similar in appearance to S. obatera Wu, 2011 (Fig. 3), but can be distinguished from the latter by comparing the antenna, forewing and abdomen. The male antenna of S. simianshana is long, and slightly thicker than that of S. obatera; the postmedial line of the forewing is black and broken, running from the apex to the posterior margin at ca. 1/3 distance from the wing base; the abdomen is dark brown posteriorly. The male antenna of S. obatera is thin; the forewing postmedial line is pale grey and it runs from the apex to the posterior margin at ca. 3/4 Figures 1-6. Striogyia spp., adults and male genitalia, with 8th sternite: 1, 2. S. simianshana sp. nov., male, holotype; 3, 4. S. obatera Wu, 2011, Prov. Jiangxi, China, genitalia No. WuJ-325-1; 5, 6. S. acuta Wu, 2020, holotype (after Wu 2020) a: phallus, b: male genitalia, c: 8th sternite. Scale bars: adults, 5 mm; male genitalia, 1 mm. from the wing base; the abdomen is yellow posteriorly. The visible difference in appearance between this new species and S. acuta (Fig. 5), and other congeners is that the latter have a distinct discal spot or a complete postmedial line on the forewing.
In the male genitalia, the new species is similar to S. acuta (Fig. 6), but also displays significant differences. In S. simianshana, the apex of the valva is rounded; the paired ox horn-shaped processes are strongly curved outwards, with a broad base; and the plate in the apex of the phallus is nearly triangular (Fig. 2). The valva of S. acuta is narrower than that of S. simianshana; the pair of processes is only slightly curved outwards, with a narrow base; and the plate in the phallus apex is almost rectangular (Fig. 6). The new species shows visible differences in the male genitalia compared to S. obatera (Fig. 4) with the apical process of juxta in S. obatera being chimney-shaped, while the structures of the other two species are pointed.
Thorax. Mainly grey with a few greyish brown scales; tegula pale grey. Forewing base colour greyish-brown, while the colors of the base, costal margin, and terminal areas are darker and mixed with black spots; the black, oblique, broken postmedial line running from the apex to 1/3 of the posterior margin; terminal line dark brown; fringe greyish-white to dark brown. Hindwing base colour dark brown, while the colour of costal margin area is paler; terminal line distinct, brown and the fringe is brown. Abdomen. Dorsally yellowish-brown to dark brown, with mixed yellow and black; 8th sternite ( Fig. 2c) slightly sclerotised, concave in distal margin, bearing dense spines.
Male genitalia (Fig. 2a, b). Uncus and gnathos absent. Tegumen narrow, weakly sclerotised. Valva long, extremely narrow at base, rounded at apex; 1/2 of the costa from the base part of valva weakly sclerotised, almost transparent and membranous; the base of sacculus slightly upheaved, with a small triangular process. Transtilla strongly sclerotised, bearing a pair of long, ox hornshaped processes curved outwards, distinctly broader at the base. The juxta consisting of two parts, the apical part three pronged; the basal part ring-shaped, with width greater than height. Vinculum ring-shaped. Saccus inconspicuous. Phallus slender, longer than the valva, a nearly triangular plate formed on one side of the apex, densely bearing saw-toothed small spines on the edge.
Female. Unknown. Distribution. China (Chongqing Municipality: Mt. Simian) (Fig. 7A). Etymology. The species is named for its type-locality in Mt. Simian, Chongqing, China. Bionomics. The moths fly in July. The specimens were collected with a light trap close to a subtropical mixed forest (Fig. 7B).
Remarks. The Simian Mountain Nature Reserve is located in the southwest of Chongqing Municipality. The region has a subtropical humid monsoon climate with abundant rainfall, and the vegetation types are mainly tropical and subtropical coniferous and broad-leaved mixed forests.
The main vegetation found around the site where the specimen was collected include Fagus longipetiolata Seemen (Fagaceae), Castanopsis fargesii Franch. (Fagaceae), Engelhardia roxburghiana Wall. (Juglandaceae), Fokienia hodginsii (Dunn) A.Henry & H.H.Thomas (Cupressaceae), different kinds of bamboo, and a large number of shrubs and ferns growing in the ground cover layer of the forest. However, the larval host of this species is yet to be determined as no specimens have been collected in its immature stage.
The distribution of the Chinese Striogyia species is provided (Fig. 8).