Bombyciellalinzhiensis, a new species from southern Xizang, China (Lepidoptera, Noctuidae, Noctuinae)

Abstract A new species of the genus Bombyciella Draudt, 1950, Bombyciellalinzhiensissp. nov., is described from the Linzhi (Nyingchi) Prefecture in southern Xizang (China), following a diagnostic comparison with B.talpa Draudt, 1950 and B.antra Saldaitis, Benedek, Behounek & Stüning, 2014. The adults and the male genitalia of the new and related species are illustrated.


Introduction
Bombyciella Draudt, 1950 is a noctuid genus distributed in mountain areas in southwestern and northern China. The genus is closely related to the Holarctic Brachylomia Hampson, 1906(Saldaitis et al. 2014) and belongs to the subtribe Xylenina of the tribe Xylenini of the subfamily Noctuinae (Lafontaine and Schmidt 2010;Zahiri et al. 2011). The genus has recently been revised by Saldaitis et al. (2014) and currently comprises two valid species. The male genitalia structures of Bombyciella and Brachylomia are very similar and display no distinctive apomorphic features. Therefore, it is possible that these taxa represent one genus, an issue that can be resolved in the future by using molecular methods through a multi-gene phylogenetic analysis covering these and other related genera.
During an entomological survey in the southern Xizang Province of China, a long series of unusual dark-coloured Bombyciella specimens was collected by the senior and the second authors. After comparing the male genitalia structures of these specimens with the other two species in the genus, they proved to be diagnostic and the specimens are therefore considered to represent a new species which is here described.

Materials and methods
Abbreviations for private and institutional collections used herein are as follows: The male genitalia terminology follows Fibiger (1997) and Kononenko (2010).  Draudt, 1950 (Figs 7, 8), but it can be distinguished by its darker body colouration, the more tapered forewing apex, the more indistinct transverse lines of the forewing and the dark grey hindwing having a distinct discal spot, whereas in B. talpa the hindwing is pale brown and the discal spot is absent or faint. Bombyciella linzhiensis sp. nov. differs clearly from another congener, B. antra Saldaitis, Benedek, Behounek & Stüning, 2014 (Fig. 6), by its significantly smaller size (the forewing length is 26 mm vs 39 mm in B. antra), the blackish brown head and thorax (bluish grey in B. antra), the blackish brown abdomen (pale brown in B. antra), the straight costal margin (slightly convex in B. antra), the more convex outer margin of the forewing, the blackish brown or olive brown forewing colouration (it is bluish grey in B. antra), and the dark grey hindwing with a distinct discal spot (whereas in B. antra the hindwing is pale brown with a grey suffusion and lacks a discal spot but has a diffuse thin transverse line). The male genital capsule of B. linzhiensis sp. nov. (Figs 9, 10) is reminiscent of that of B. talpa ( Fig. 11) but differs by the wider uncus, the considerably smaller, tubercle-like medioventral process of juxta, the more apically rounded valva, the downward pointing and evenly-wide clasper tapered only apically (it is subapically constricted with an upward pointing apex in B. talpa), and the thicker and longer costal process. Additionally, the peniculus of the new species is shorter than in B. talpa and the saccus is somewhat shorter and narrower. The aedeagus of B. linzhiensis sp. nov. is shorter (in relation to the tegumen-vinculum complex) and less sub-proximally curved than in B. talpa. The carina of the new species bears a bunch of spines directed ventrally whereas that of B. talpa bears a row of laterally directed spikes. The vesica of B. linzhiensis sp. nov. is broader than that of B. talpa and bears distally a cluster of more robust spike-like cornuti. Compared to that of B. antra (Fig. 12), the male genital capsule of B. linzhiensis sp. nov. has a more distally elongated and apically obtuse uncus (apically pointed in B. antra), a basally wider and less elongated valva having a straight dorsal margin and a well-developed costal process protruding beyond the ventral margin, whereas in B. antra the dorsal margin of valva is medially slightly convex and distally somewhat curved dorsally, and the costal process is reduced. The clasper of the new species is thicker and evenly down-curved whereas it is up-curved in B. antra. Additionally, the peniculus of the new species is shorter and narrower than that of B. antra, the juxta is  markedly longer and the saccus is narrower and somewhat longer. In the aedeagus of B. linzhiensis sp. nov., the carina bears a bunch of spines whereas it is plate-like without spines in B. antra. The vesica of the new species is somewhat shorter and broader (in proportion to the aedeagus size) than in B. antra and bears a cluster of markedly shorter cornuti distally.

Noctuidae
Description. Male. Forewing length 26-27 mm (holotype: 26 mm). Antenna shortly bipectinate. Head and thorax blackish grey with suffusion of pale grey scales. Forewing triangular with tapered apex and almost straight costa and convex termen. Forewing ground colour varies from blackish brown to olive brown. Subbasal dash short, black. Antemedial line irregularly sinuous, black, indistinct, oblique outwards posteriorly. Postmedial line indistinct, dentate on veins, loop-like curved anteriorly and oblique inwards posteriorly. In olive brown form, medial area intensely suffused with black scales. Orbicular stigma elliptical, from greyish-to olive brown. Reniform stigma wide, slightly dilated anteriorly, from greyish-to olive brown. Subterminal line evenly curved, parallel to termen, brown, interrupted into diffuse spots on veins. Terminal line blackish brown, thin. Costal margin intensely suffused with blackish scales, with three thin and short whitish subapical dashes. Cilia from dark grey to blackish grey. Hindwing dark grey with brown suffusion on veins, thin brown terminal line and comma-like, dark brownish grey discal spot. Hindwing cilia brownish grey. Abdomen blackish brown, with suffusion of pale grey scales along segment edges.
Female. Unknown. Distribution. The new species is known only from Sejila Mountain in southern Xizang Province of China (Figs 13, 14).
Etymology. The specific epithet refers to the type locality located in the Linzhi (Nyingchi) prefecture of Xizang.  Science Foundation of China (Grant No. 31760631), and Tutor innovation project of Forestry Subject of Tibet agricultural and Animal Husbandry University (Species diversity and conservation of Geometridae (Lepidoptera) in southeastern Tibet). Anton Volynkin, Aidas Saldaitis and Balazs Benedek had no funding. We express our sincere thanks to National Forest Ecosystem Observation and Research Station of Nyingchi Tibet, United Key Laboratory of Tibet plateau ecological security, and South-East Tibetan plateau Station for integrated observation and research of alpine environment in Linzhi. We are also indebted to Dr Dieter Stüning (Bonn, Germany) for pictures of the holotype of B. talpa provided.