Taxonomical study on the newly-recorded genus Falsonnannocerus Pic from China (Coleoptera, Tenebrionidae, Stenochiinae)

Abstract Background The genus Falsonannocerus Pic, 1947 (Coleoptera, Tenebrionidae, Stenochiinae, Cnodalonini) includes 13 known species occurring in West Africa, South Asia and Southeast Asia. The bionomics of species in this genus are unknown. New information The genus Falsonnannocerus Pic, 1947 is recorded for the first time from China, including two species: F.thailandicus Masumoto, 1986 from Yunnan and F.haizhuensis sp. n. from Guangdong. Morphological characters of the two species are illustrated and compared. The photographs of female reproductive system, which were never shown for this genus before, are also presented.

In the present paper, we describe or re-describe two Falsonannocerus species: F. thailandicus Masumoto, 1986 from Yunnan Province, southwest China and F. haizhuensis sp. n. from Guangdong Province, southeast China, representing the first record of the genus from China. Important distinguishing morphological characters of the two species are illustrated with colour plates. The female reproductive system of the genus is provided.

Materials and methods
Specimens were relaxed and softened in hot water for 24 hours, then transferred to distilled water to clean, observe and dissect. In order to examine the genitalia of both sexes, the abdomens were detached and treated with a 10% solution of potassium hydroxide (KOH) for 12 hours, then transferred to distilled water to flush the remaining KOH and stop any further bleaching. After examination, the body parts were mounted on a glass slide with Euparal Mounting Medium for future studies. Photographs of the habitus were taken using microlens on a Canon 5D IV. Detailed photographs with flashlight were performed using a Olympus 10X microlens with a Canon 5D IV. The final deep focus images were created with Zerene Stacker 1.04 stacking software. Adobe Photoshop CS6 was used for post-processing. The terminology adopted in the paper for ovipositor and female genital tubes follows Tschinkel and Doyen (1980). The material examined for this study is deposited in the following private and public collections: CJZG: collection of Jiang Zhu, Guangzhou, Guangdong, China; CDYZ: collection of Deyao Zhou, Shanghai, China; MYNU: insect collection of Mianyang Normal University, Mianyang, China; NSMT: National Science Museum, Tsukuba, Japan.
Measurement criteria in millimetres (mm) are as follows: antennal length: length between the base of scape and the apex of ultimate antennomere; body length: length between the apices of mandibles and the elytral apices along the mid-line; elytral length: length between the basal border and the apex of elytra along suture; elytral width: widest part of both elytra combined; head length: length between the anterior margin of epistoma and the anterior margin of pronotum along the mid-line; head width: widest part of head (including eyes); pronotal length: length of the pronotum along the mid-line; pronotal width: widest part of pronotum.
Legs. Femora weakly dilated. Tibiae straight, more or less clavate; protibiae slightly bent near apex of lower side. Tarsi stout. Femora and tibiae densely and coarsely punctate. Setae longer and denser in lower sides of all legs.
Elytra elongate, 2.3 times as long as widest part, widest at apical 3/7. Elytra strongly convex in lateral view, especially in apical half. Lateral margins gradually widened from humeri to apical 3/7, then gradually narrowing to rounded apices. Each elytron with nine irregular rows of close and coarse punctures and short scutellary row in basal 1/6; intervals feebly convex and sparsely covered with small tubercles throughout. Epipleura wide at base, narrowing towards apex and terminating near apex and sparsely and finely punctate. Hind wings fully developed. Mesoventrite weakly convex towards middle, sparsely punctate, denser posteriorly. Mesepisternum and mesepimeron both triangular, densely punctate. Metaventrite densely punctate and finely grooved along mid-line in posterior half. Metepisternum rather long and thin, densely punctate.
Legs. Femora weakly dilated. Tibiae straight, more or less clavate; protibiae slightly bent near apex of lower side. Tarsi stout. Femora and tibiae densely and coarsely punctate. Setae longer and denser in lower sides of all legs.
Abdomen. Abdominal sternites III-VI transverse, almost equal in length, densely punctate; intercoxal process on sternite III large, subtriangular; sternite VII semicircular, widely rounded at posterior margin; sternite VIII ( Fig. 12a) rounded at posterior margin, disc largely membranous; spiculum ventrale rather long and slender. Abdominal tergite VII semicircular, widely rounded at posterior margin; tergite VIII ( Fig. 12b) slightly emarginate at middle of posterior margin, with wide longitudinal membranous area along mid-line. Defensive glands with two large membranous pouches as shown in Fig. 11.

Diagnosis
Except for Falsonannocerus thailandicus Masumoto, 1986 re-described above and F. tsuyukii Masumoto, 1986 from Thailand, F. haizhuensis sp. n. is readily differentiated from other congeners by the combination of the following characters: body colour is without colourful metallic lustre; pronotum is subcylindrical, with its length equal to width; intervals of puncture rows on elytra are covered with small tubercles throughout. For the former two species, the new species can be distinguished from them by the following characters: In F. thailandicus, body colour is mostly reddish-brown, dull (Figs 1, 2a); gula is strongly wrinkled (Fig. 3a); antennomere V is wider than long, 1.4 times as wide as long (Fig. 4a); pronotum is covered with dense, well-defined, coarse, deep and subcircular punctures and intervals are distinctly carinate (Fig. 3c); pronotal posterior corners are slightly projected, acute (Fig. 3c); prosternal process with its apex reaching posterior margin of procoxae (Fig. 3e); intervals of puncture rows on elytra are densely covered with small tubercles throughout (Fig. 1a); vagina is rather slender in the anterior part, adruptly inflated in the posterior part (Fig. 9a); spermathecal duct is long, about 1.7 times as long as ovipositor (Fig. 9a). While in F. haizhuensis sp. n., body colour is mostly blackish, dull (Fig. 10); gula is almost smooth (Fig. 3b); antennomere V is longer than wide, 1.3 times as long as wide (Fig. 4b); pronotum is covered with dense, illdefined, coarse, shallow and subcircular punctures and intervals are vaguely carinate (Fig. 3d); pronotal posterior corners are obtusely rounded (Fig. 3d); prosternal process with its apex reaching posterior margin of prothorax (Fig. 3f); intervals of puncture rows on elytra are sparsely covered with small tubercles throughout (Fig. 10a); vagina is slender in the anterior part, almost gradually inflated in the posterior part (Fig. 9b); spermathecal duct is short, about 3/4 length of ovipositor (Fig. 9b).
In F. tsuyukii, body colour is mostly reddish-brown, lustrous (Fig. 2b); pronotum is rounder and more convex, 1.2 times as wide as long (Fig. 2b); elytra is widest at the middle (Fig. 2b); intervals of puncture rows on elytra are sparsely scattered with fine tubercles in anterior portion (Fig. 2b). While in F. haizhuensis sp. n., body colour is mostly blackish, dull (Fig. 10); pronotum is subcylindrical and less convex, with its length equal to width (Fig. 3d); elytra is widest at the apical 3/7 (Fig. 10a); intervals of puncture rows on elytra are sparsely covered with small tubercles throughout (Fig. 10a).

Etymology
The specific epithet is from the Chinese name (Pinyin) of the type locality "Haizhu National Wetland Park". The name is an adjective.