A review of the dragon millipede genus Desmoxytes Chamberlin, 1923 in China, with descriptions of four new species (Diplopoda, Polydesmida, Paradoxosomatidae)

Abstract Four new species of Desmoxytes are described from southern China: Desmoxytes lingulata sp. n., Desmoxytes parvula sp. n., and Desmoxytes nodulosa sp. n., from Guangxi Zhuang Autonomous Region, and Desmoxytes getuhensis sp. n. from Guizhou Province. In addition, new records of Desmoxytes scutigeroides Golovatch, Geoffroy & Mauriès, 2010 and Desmoxytes scolopendroides Golovatch, Geoffroy & Mauriès, 2010 are provided, with a modified key to Desmoxytes species currently known to occur in China. Two of the new species, Desmoxytes nodulosa sp. n. and Desmoxytes getuhensis sp. n., seem to be troglobites.


Introduction
Desmoxytes Chamberlin, 1923 is a large, common, rather well defined, southeast Asian genus of the basically oriental millipede tribe Orthomorphini, subfamily Paradoxosomatinae, family Paradoxosomatidae (Golovatch et al. 2012). The genus is one of the very few among paradoxosomatid millipedes which not only harbours troglobitic species, but also bears its own vernacular name, the "dragon millipedes", labeled so to emphasize the unusually prominent, wing-, spine-or antler-shaped paraterga. At the moment, Desmoxytes is represented by 29 species, usually aposematic, brightly coloured and surface-active, ranging from southern China in the north, through Indochina, down to approximately the middle of Malay Peninsula within both Thailand and Malaysia in the south (Golovatch et al. 2012). Only one species, D. planata Pocock, 1895, has attained a vast, nearly pantropical distribution through human agency (Nguyen and Sierwald 2013).
The present paper describes a further four new species of Desmoxytes, two of which seem to be troglobites, as well as provides new records of two known presumed troglobitic congeners.

Material and methods
The holotypes and a number of paratypes are deposited in the zoological collection of the South China Agricultural University, Guangzhou, China (SCAU), with some material also to be housed in the Institute of Zoology, Chinese Academy of Sciences, Beijing, China (IZAS), and Zoological Museum, State University of Moscow, Russia (ZMUM). The methods and terminology used are after Golovatch et al. (2012).
Remarks. This species seems to be especially similar to D. cornuta Zhang & Li, 1982, from Guangxi, Guilin, Yangshuo. Obvious differences lie in a peculiar linguiform sternal process between ♂ coxae 5, combined with the stout, curved gonopod femorite and a condensed solenophore in D. lingulata sp. n., as opposed to an elongated and suberect one in D. cornuta (cf. Zhang and Li 1982). Paratype. 1 ♀ (SCAU), same locality and collecting data as of the holotype. Name. To emphasize the small size of this species. Diagnosis. Differs from congeners in the combination of spiniform paraterga, a paramedian pair of subtrapzoidal processes between ♂ coxae 4, the humped ♂ femur 6, and certain details of gonopod structure.
Remarks. Even though this species has been taken from a cave, it hardly represents a true cavernicole as it is rather strongly pigmented and shows short antennae and legs. Name. To emphasize the humped ♂ femora 5-7. Diagnosis. Differs from congeners in most of the paraterga being wing-shaped, combined with the humped ♂ femora 5-7, the sternal process present between ♂ coxae 4, occasionally also between ♂ coxae 3, as well as a short gonopod femorite and a strongly condensed solenophore.
Remarks. Although the coloration of this species is quite variable, based on several troglomorphic traits such as some individuals being completely unpigmented, and the antennae and legs clearly elongated, this species may well be a troglobite.  Diagnosis. Differs from congeners in the paraterga being long and spiniform throughout, and the antennae and legs very long, combined with setose tubercles between ♂ coxae 4, the humped ♂ femur 6, and the gonopods strongly condensed.
Remarks. Based on several troglomorphic traits such as some individuals being nearly unpigmented, and the antennae and legs very strongly enlongated, this species seems to be a troglobite.

Desmoxytes scutigeroides Golovatch, Geoffroy & Mauriès, 2010
Desmoxytes scutigeroides Golovatch, Geoffroy & Mauriès, 2010: 58 Remarks. This species has been described from a few caves in Huanjiang County, Guangxi, China while the new samples derive from two caves in the neighbouring Du'an County, Guangxi. The above material is in good agreement with the original description by Golovatch et al. (2010).

Desmoxytes scolopendroides Golovatch, Geoffroy & Mauriès, 2010
Desmoxytes scolopendroides Golovatch, Geoffroy & Mauriès, 2010: 60. Desmoxytes scolopendroides -Nguyen and  Remarks. This species has been described from a cave in Huanjiang County, Guangxi, China while the new samples come from a few more caves in the neighbouring Du'an County, Guangxi. The above material is in good agreement with the original description by Golovatch et al. (2010).