A new species of Trichopeltis Pocock, 1894 from southern China, with a checklist and a distribution map of Trichopeltis species (Diplopoda, Polydesmida, Cryptodesmidae)

Abstract The millipede genus Trichopeltis Pocock, 1894 contains 12 described species including a new species from southern China described here. Trichopeltis sutchariti sp. n. can be distinguished from congeners by its gonopods that are strongly caudolaterally curved and have a prominent, high, curved, densely setose process on each coxa. An updated checklist and a distribution map are provided for all species of the genus.

Trichopeltis has recently been reviewed and a key provided (Liu et al. 2017). At present, this genus encompasses eleven species that range from the Himalayas of India (Assam and Darjeeling District) and Myanmar to southern China, Laos, Vietnam and Indonesia (Sumatra) (Fig. 5). Five of the species are presumed troglobites: one in Laos, the other four in southern China (Golovatch et al. 2010;Golovatch 2016;Golovatch and VandenSpiegel 2017;Liu et al. 2017). Below the description of one more new congener is presented, the first to be found epigeically in China. A catalogue to all presently known species is also provided, as well as a map showing their distributions.
Since a key to all hitherto known species of Trichopeltis is available (Liu et al. 2017), no update is needed.

Materials and methods
The material was collected from a limestone mountain area in Yunnan, southern China in October 2016. Photographs of live animals were taken in the laboratory using a Nikon 700D digital camera with a Nikon AF-S VR 105 mm macro lens. Specimens were preserved in 75% ethanol, and morphological investigations were carried out in the laboratory with the help of an Olympus SZX7 stereo microscope. Scanning electron micrographs (SEM) were taken with a JEOL, JSM-5410 LV microscope with no metallic coating, and the material returned from stubs to alcohol upon examination. Images of one holotype gonopod were taken in the laboratory and assembled using the "Cell D " automontage software of the Olympus Soft Imaging Solution package. The holotype and most of the paratypes are housed in the Museum of Zoology, Chulalongkorn University (CUMZ), Bangkok, Thailand. A paratype has also been donated to the collection of the Zoological Museum, State University of Moscow, Russia (ZMUM), as indicated in the text.
The collecting site was located by GPS using the WGS84 datum.
In the catalogue sections, D stands for the original description and/or subsequent descriptive notes, K for the appearance in a key, L for the appearance in a species list, R for a new subsequent record, and M for a mere mention. Description. Superficially, a typical genus of Cryptodesmidae, distinguished from other genera in the following combination of characters, the gonopodal ones being the most important. Body small-to medium-sized (ca 8-21 mm long, ca. 1.7-5.5 mm wide), with 20 segments. Collum flabellate, much broader than head, fully covering it from above; eleven radii at collum's fore margin dividing it into 12 (sub)equal sectors; dorsal surface tuberculate to areate. Metaterga distinctly tuberculate to areate, usually setose, with at least two irregular transverse rows of tuberculations extending onto paraterga. The latter very short and very wide, subhorizontal, multilobulate at least at caudal and lateral margins. Ozopores highly variable, usually untraceable, when present then barely visible, located near base of paraterga either entirely dorsally or partly dorsally and mainly ventrally, or entirely ventrally. Only coxae 7 or both coxae 6 and 7 distinctly separated to accommodate tips of gonopods. Gonopod aperture usually subcordiform, edges with little or no elevation.

Family
Gonopods ranging from rather simple to relatively complex (Fig. 4), small, usually foliate and held subparallel to each other; telopodites short to rather short, only slightly longer than coxae; the latter usually either bare or poorly setose, more rarely densely setose. Cannula usual, long, slender and falcate, normally not subtended by a median projection of coxa. Prefemoral (setose) part of telopodite making up 1/3-1/2 of the whole; acropodite either distinctly branched (usually with three branches, including an inconspicuous solenomere) or more or less deeply notched apically, seminal groove running entirely on mesal face to end on a more or less distinct caudo-apical solenomere.  (Attems, 1938) Records from Indonesia. West Sumatra, Singkarah, 1,800 m a.s.l. (Pocock 1894;Jeekel 1955); Anai Cleft, 500 m a.s.l. (Jeekel 1955).

Record from China. Hunan Province, Chenzhou City, Linwu County, Xianghualing
Town, Cave II Dong (Liu et al. 2017).  Name. Honours Jirasak Sutcharit (CUMZ), one of the collectors. Differential dagnosis. This new species seems to be particularly similar to T. bellus Liu, Golovatch &Tian, 2017 andT. intricatus Liu, Golovatch &Tian, 2017, both from caves in southern China (Liu et al. 2017), since they all are distinguished by the presence of abundant long setae on the lateral face of the gonopodal coxae, and by highly complex gonopodal telopodites. However, T. sutchariti sp. n. differs from them,  as well from all other congeners in that its gonopodal telopodites are noticeably curved caudolaterad, and there is a strong, curved, laterally densely setose process (cxp) on each of the gonopodal coxae (Fig. 4).
Remarks. All five specimens were taken from a rather large population found on limestone rocks, as well as on tree trunks during the rainy season. It seems noteworthy that the surface structures illustrated in the new species, such as the sculpture of the prozonae and the shape of the limbus (Fig. 2H, I), perfectly match the findings of Akkari & Enghoff (2011) in other genera/species of the same family.

Conclusions
At present, the genus Trichopeltis comprises 12 species ranging from the Himalayas of India (one species), through Bangladesh (one species), Myanmar (three species), to China (five species), Laos (three species), Vietnam, Cambodia and Indonesia (one species each) (Fig. 5).
Most of the species seem to be highly localised endemics, this being especially true of the five presumed troglobionts. There are only three congeners, all epigean, which are relatively widespread: T. kometis, found in Vietnam, Laos and Cambodia; T. feae, recorded from several localities in Myanmar; and T. watsoni, reported from Mynamar, Bangladesh and the Himalayas of India (Fig. 5).
Such a distribution pattern of Trichopeltis clearly suggests its Indo-Malayan (= Oriental) roots and there is little doubt that more new and interesting species will be discovered and additional localities recorded in future.