The millipede family Cryptodesmidae in Indochina (Diplopoda, Polydesmida)

Abstract In addition to two species of the diplopod family Cryptodesmidae already reported from Indochina, Trichopeltis kometis (Attems, 1938) and Ophrydesmus anichkini Golovatch, 2015, the fauna of that region is supplemented by three species: Niponia nodulosa Verhoeff, 1931, a millipede hitherto known only from southern Japan and Taiwan, is now recorded from Vietnam; Trichopeltis cavernicola sp. n. from Laos, the sixth species in that tropical Asian genus, is the first presumed troglobite to be described amongst the Asian cryptodesmids and shows several distinct troglomorphic features; and Circulocryptus gen. n., monobasic, which joins the tribe Dyakryptini, but differs from all three contribal genera (two monobasic from Borneo, and another, oligotypic, from New Guinea) primarily in the gonopods of Circulocryptus faillei sp. n., from Vietnam, being especially elaborate and subcircular, the telopodites strongly twisted, and the solenomere lying much more basally.


Introduction
In tropical or subtropical Asia and Australasia, the millipede family Cryptodesmidae currently comprises only 11 genera (including two that are dubious) and 34 species. Among them, only two genera and species, Trichopeltis kometis (Attems, 1938) (= T. deharvengi Golovatch, Geoffroy, Mauriès & VandenSpiegel, 2010) and Ophrydesmus anichkini Golovatch, 2015, occur in Indochina, the former species being quite wide spread in Vietnam, Laos and Cambodia, the latter species described from a single local ity in southern Vietnam (Golovatch 2015, Golovatch andAkkari 2016).
This paper puts on record another three Cryptodesmidae found in Indochina. One represents a new genus and species from Vietnam. One more is a new species of a rather small tropical Asian genus from a cave in Laos, the first presumed troglobitic Asian cryptodesmid. The third species is common in southern Japan and Taiwan, be ing reported here for the first time from Indochina, in particular, northern Vietnam.

Material and methods
The types of both new species were collected by my French colleagues and friends Lou is Deharveng and Anne Bedos, both from the Muséum national d'Histoire naturelle, Paris (MNHN), France, and Arnaud Faille, from the Bayerische Zoologische Staats sammlung, München (ZSM), Germany, and are now deposited in MNHN. The sam ples of Niponia nodulosa Verhoeff, 1931, were taken by friend Dmitri N. Fedorenko (Moscow, Russia), and are now housed in the Zoological Museum of the Moscow State University, Moscow (ZMUM), Russia. Focus stacking pictures were taken by Jonathan Brecko, of the Royal Museum for Central Africa, Tervuren (MRAC), Belgium.
Remarks. Based on material from Taiwan, this species has recently been rede scribed and illustrated in due detail (Golovatch et al. 2011). It is common in southern Japan and Taiwan (Golovatch et al. 2011), erroneously reported also from continental China (Golovatch et al. 2010). The Vietnamese samples fully agree with the detailed account given by Golovatch et al. (2011). Name. To emphasize the cavernicoly and troglomorphic appearance of this new species; noun in apposition.
Diagnosis. Differs from congeners by the relatively gracile and slender body in which each midbody paratergite is clearly narrower than prozonite width, coupled with the increasingly upturned postcollum paraterga and such obviously troglomor phic features as an unpigmented body, as well as the extremely long and slender legs and antennae. In addition, much of the distolateral part of an indistinctly tripartite gonopod telopodite is densely covered with wartshaped knobs while the tip of the solenomere is vestigial and simple.
The new species is not only the first clearly troglomorphic Trichopeltis, but also the first presumed troglobite among the Asian Cryptodesmidae. Similarly strongly cave adapted cryptodesmids are exceptional, e.g. the highly troglomorphic Peridontodesmella alba Schubart, 1957, from several caves in São Paulo State, Brazil (Trajano et al. 2000).
Name. To emphasize the subcircular gonopods; gender masculine. Description. Smallsized Cryptodesmidae (adults about 1 cm long and 3 mm wide) with 20 segments (trunk composed of collum plus 17 podous and one apodous rings, plus telson); a flabellate collum covering the head from above. Antennae clearly clavate. Paraterga short and very broad, slightly declined, mostly squarish laterally, lobulate and/or radiate anteriorly, laterally and posteriorly; ozopores invisible, pore formula untraceable. Middle parts of metaterga with seriate transverse rows of abun dant setigerous knobs/tubercles partly extending onto paraterga; tergal setae present, simple; neither sternal cones nor leg modifications. Gonopod aperture subcordiform; gonopod telopodites in situ held parallel to each other, each vaguely bipartite and complex, with a mesal, parabasal, prefemoral process; basal part of telopodite clearly twisted and surmounted by a long, spiniform solenomere terminating a sigmoid semi nal groove and situated at about telopodite midway. Neither an accessory seminal chamber nor a hairy pulvillus.
Type-species. Circulocryptus faillei sp. n. Remarks. Globally, the Cryptodesmidae is a relatively small family that encom passes almost 40 genera and nearly 130 species and ranges from Mexico to Argentina in the Americas, occurring also in tropical Africa and tropical to subtropical Asia to Papua New Guinea and Japan in the East (Minelli 2015). Only three genera have hith erto been known in the entire family, in which the gonopod shows a distinct prefemo ral process arising mesally near the origin of the seminal groove: Astrolabius Verhoeff, 1931, with 2 species from Papua New Guinea (Golovatch et al. 2010), Dyakryptus Hoffman, 1961, monobasic, from Eastern Malaysia, Sabah, Borneo (Hoffman 1961, 1980), and Sarissocryptus Hoffman, 1993, monobasic, from Eastern Malaysia, Sarawak, Borneo (Hoffman 1993. This process can be completely mesal (Astrolabius) or be twisted laterad (Dyakryptus and Sarissocryptus). Based of the above synapomorphy in gonopod structure, i.e. the presence of a basal prefemoral process, coupled with a co herent distribution pattern in Borneo and New Guinea, these three genera form the tribe Dyakryptini Hoffman, 1973(Golovatch 2015. Circulocryptus gen. n. definitely joins this trio, but differs in the gonopods being especially elaborate and subcircular (versus far from so elaborate and not too strongly curved), the telopodites distinctly twisted basally (versus not twisted), and the solenomere lying much more basally, close to telopodite midlength (versus subapical). The range of Dyakryptini is thus consi derably extended into continental SE Asia. Name. Honours Arnaud Faille, the collector. Description. Length ca 11 mm, width of midbody pro and metazonae 1.2 and 2.9 mm, respectively. General coloration in alcohol red, but legs mostly somewhat lighter pink and antennomeres 57 increasingly infuscate, redbrown to dark brown (Figs 8,9).
Gonopods (Figs 11, 12) very complex, in situ both held parallel to each other (Fig. 9). Telopodite subcircular, very strongly curved caudad, vaguely bipartite, at very base with a short, prefemoral, fingershaped, trichostelelike process (t). Basal part (b) stout, extended terminally into a long, solid, spiniform, retrorse, laterally curved and densely pilose solenomere (sl), the latter at its base bearing a short, slightly curved, api cal process (pr); seminal groove (sg) sigmoid, mostly running on lateral face of b, this being evidence of b torsion. Acropodite about half as long as telopodite, supplied with a subtriangular, midway, membranous lobe (l) and a large apical uncus (u) showing two caudal, parallel and strongly adjacent rows of simple or bifid spinules (s) before u branching into two peculiar apical structures, one a lateral spatuliform process (p) (in situ directed strongly laterad), the other a mesal subunciform lappet (la) with a smaller ventral hook (h) at base. Neither an accessory seminal chamber nor a hairy pulvillus.
wishes to extend his gratitude to the RussiaVietnam Joint Tropical Centre, which supported his collecting trips to Vietnam. The 2011 field trip of L. Deharveng and A. Bedos to the Khammouane karst in Laos was funded by the MNHN ATM (Action Transversale Muséum) « Biodiversité actuelle et fossile -Crises, stress, restaurations et panchronismes: le message systématique ». The 2013 field work in the Hon Ba Nature Reserve in Vietnam was funded by the LabEx BCDiv (Diversités Biologiques et Cul turelles) through the MNHN, Paris (grant of the Agence Nationale de la Recherche for the LabEx ANR10LABX0003BCDiv, in the framework of the programme « Investissements d'Avenir, ref. n° ANR11IDEX000402), the trip of Arnaud Faille was supported by the German Research Foundation (DFG project FA142F/11). The field trip to Hon Ba was made possible thanks to Truong Quang Tam (Institute of Tropical Biology, Ho Chi Minh City) and the staff of the Hon Ba Nature Reserve.