The millipede tribe Nedyopodini, with special reference to the fauna of Taiwan (Diplopoda: Polydesmida: Paradoxosomatidae)

The east and southeast Asian millipede tribe Nedyopodini is here restricted to a single genus, Nedyopus Attems, 1914; the following genera are here considered to be junior subjective synonyms: Vaulogerodesmus Brölemann, 1916, Nesodyopus Verhoeff, 1940, n. syn., and Varyomorpha Wang, 1957, n. syn. This taxonomically confused tribe/genus is reviewed and redefined. Based on new collections, the fauna of Taiwan currently contains five Nedyopus species including the redescribed N. hsientienensis (Wang, 1957) and N. pectinatus (Wang, 1957), both n. comb. ex Varyomorpha, as well as the newly described N. caudatus n. sp., N. latus n. sp., and N. wui n. sp. A key to these five species is provided.


Introduction
The tribe Nedyopodini is one of the most characteristic elements in the paradoxosomatid fauna of east and southeast Asia. It is defined by the parabasally enlarged gonopod femorite that, due to its torsion, supports the seminal groove on the lateral side (Jeekel 1968). Hoffman (1980) considered the tribe as encompassing the following genera: Nedyopus Attems, 1914, with eight to nine species from Japan, China, and Korea; Nesodyopus Verhoeff, 1940, with one species from Bonin Islands, Japan; Vaulogerodesmus Brölemann, 1916, with two species from Indochina; and Varyomorpha Wang, 1957, with two species from Taiwan. However, the latter genus was incorporated into this tribe with some reservation.

Systematic part
Because the taxonomy of the Nedyopodini is so badly confused, and given that the available material derives only from Taiwan, a full revision is not attempted here. It is necessary to amass and study much more material, including the existing types and new collections, to clarify the status of the Japanese, Korean, and Sumatran members. Instead, we focus on the fauna of Taiwan, which alone is sufficiently diverse to justify several important changes to the classification of the tribe. This group currently comprises a single, highly variable and quite speciose genus, for which the name Nedyopus has priority. Following Attems (1937), we consider Vaulogerodesmus as a subjective junior synonym of Nedyopus. Furthermore, since Nesodyopus and Varyomorpha are also synonyms of Nedyopus, the whole tribe Nedyopodini becomes monogeneric. Hence the diagnosis presented below holds for both the Nedyopodini and Nedyopus.
The fauna of Taiwan contains at least five species of Nedyopus. Based on their characteristics, this genus (and tribe) can be redefined as follows (cf . Jeekel 1968;Hoffman 1973).

Diagnosis
Usually medium-sized Paradoxosomatidae (12-48 mm long, 1.4-5.0 mm wide) with 20 body segments, a normal pore formula, modestly to poorly developed paraterga, a deep and strongly beaded stricture between pro-and metazona, short to relatively long antennae and legs, and a more or less distinct, often contrasting colour pattern. Teguments smooth to rugulose, only seldom rugose-granular in places. Tergal setae usually missing or nearly so, only rarely conspicuously dense. Pleurosternal carinae usually present, especially on segments 2-7. Male legs, especially pregonopodial ones, usually with tarsal brushes, in some species the brushes cover the distoventral parts of the tibiae. A more or less evident sternal structure between male coxae 4, ranging from a long tongue-shaped process to two small paramedian tubercles.
Gonopods with long and subcylindrical coxae, latter usually sparsely setose distoventrally. Telopodite only slightly longer than coxa; prefemoral part small, as usual densely setose and clearly delimited. Femorite elongate, strongly twisted so that seminal groove runs entirely on its lateral face, with a short, stalk-shaped basis; medial face with a more (usually) or less (seldom) strongly developed groove/excavation parabasally, demarcating a more (usually) or less (some ''Vaulogerodesmus'' species) prominent lobe/expansion (e); medial face of femorite with a more (usually) or less (some ''Vaulogerodesmus'' species) evident lobe (l) situated from about midway to distoventrally; this lobe is often irregularly shaped and denticulate, sometimes broken into two parts (l9 and l0) near its middle; solenomere rather short, flagelliform, usually with a more or less evident lobe (m) near base on dorsolateral side of femorite; solenophore (5tibiotarsus) complex, more or less strongly coiled, normally only vaguely demarcated at base from femorite, without a postfemoral sulcus, usually consisting of several hyaline lobes (up to four: A, B, C and D) nearly completely sheathing and supporting the solenomere, lobe B normally the largest and recognizable due to longitudinal ribs/rugulosity.

Remarks
The synonymy of Vaulgerodesmus is supported by the fact that several of the species studied here show a modestly enlarged gonofemorite, combined with various degrees of development of the demarcation sulcus between the femorite and the solenophore. Until recently, Vaulogerodesmus was believed to be confined to Indochina and the adjacent parts of China, comprising species with a relatively poorly grooved and modestly expanded gonopod femorite, as opposed to the particularly deeply grooved and dorsolaterally strongly expanded one observed in the Nedyopus species or subspecies from Japan and Korea. The vast geographical gap in between (i.e. central and northeastern China, as well as Taiwan) also seemed to support the separation of these two genera. However, Golovatch et al. (2003) suggested that if transitional forms were found as a result of progress in the knowledge of Nedyopodini, both Nedyopus and Vaulogerodesmus would have to be merged. The new material from Taiwan allows us to confirm that this is the case.
The synonymy of Nesodyopus stems from the very unreliable diagnosis of this subgenus originally given by Verhoeff (1940). In contrast to other Nedyopus, N. boninensis shows a considerably narrower e, a non-demarcated gonopostfemoral portion and a simple solenophore, consisting of only two lobes. This condition is strikingly similar to that observed in typical Vaulogerodesmus species. Although both Jeekel (1968) and Hoffman (1980) assigned full generic status to Nesodyopus, they emphasized that this was only provisional. Moreover, both Takakuwa (1954) and Miyosi (1959) treated N. boninensis as a typical Nedyopus, omitting Nesodyopus altogether as a genus-level taxon.
The synonymy of Varyomorpha could only be established with fresh topotypic material to hand. Because the types of Wang's species V. hsientienensis and V. pectinata are lost, it appears necessary to designate neotypes from among the available near-topotypes in order to stabilize the nomenclature and fix these names. Like Jeekel (1968), we refrain from using the terms ''lamina lateralis'' and ''lamina medialis'' to designate certain parts of the solenophore in describing the gonopod conformation of Nedyopodini. Firstly, the solenophore of Nedyopus is usually a highly complex structure, consisting of several (two to four) lobes. Secondly, the remarkably twisted gonofemorite, coupled with a no less strongly coiled solenophore, not only makes homologization difficult, but also renders the above positional terminology pointless. We entirely agree with Hoffman (1973) that, fundamentally, the solenophore in Nedyopus shows both the laminae well developed, but the correspondence between them remains unclear.
Below we provide descriptions of all five Nedyopus species that are securely documented in the fauna of Taiwan and give a key for their separation. Wang's (1955) record of N. patrioticus, like most others by this author, is regarded too dubious to be considered seriously.

Diagnosis
Differs from congeners by a contrasting colour pattern, combined with the relatively welldeveloped paraterga, the densely setose postcollar metaterga, and the gonopod-telopodite tip consisting of only two lobes.
Gonopods (Figures 8-10, 97-102) complex. Coxite elongate, subcylindrical, strongly setose distoventrally; cannula normal. Telopodite strongly twisted; prefemoral part rather short, as usual densely setose; femorite with a short stalk basally, followed by a modestly broadened, elongate, distal portion carrying a peculiar hyaline lamella (l) on medial side, with a smooth or sometimes denticulate margin; l divided in distal third into two lobes (l9 and l0); solenophore (sph) hyaline, twisted, nearly as long as femorite, with two apical lobes (a small lobe A and a large, hyaline, ribbed/rugulose lobe B), nearly completely sheathing a mostly flagelliform and rather short solenomere; seminal groove running medially on stalk of femorite, then directed abruptly laterally to follow subdorsal side of remaining portion of femorite, finally changing course ventrad onto solenomere at end of l and at base of sph; a small lamina (m) near base of solenomere on lateral side.

Remarks
This material, including the near-topotypic neotype, has been chosen as representing N. hsientienensis because it does not contradict in any way the original description (Wang 1957a), even though the latter is extremely poor. Amongst the characters that tally are the relatively small body, the dark brown coloration with a markedly light pattern, the short antennae, the poorly developed paraterga with the transverse sulcus starting from segment 5, and the complex gonopod configuration. The characteristic dense tergal setation was not mentioned by Wang (1957a), but he could have easily overlooked this, as he did for other distinctive features of this species, or else the type material might have been in too poor condition to retain the tergal setae.

Diagnosis
Differs from congeners by the black-brown coloration, combined with the long antennae, the metatergal transverse sulcus on segments 4-19, some other peculiar somatic characters (see below and key), and the gonopod telopodite tip consisting of only one large lobe with up to three marginal, shallow lobules.

times (R) as long as midbody height.
Gonopods (Figures 19-21, 103-108) complex, much as in N. hsientienensis, but lamella l with a smooth margin, divided in the middle into two similarly sized parts, end of sph either not divided into distinct lobes (Figure 19) or consisting of three lobules: A and an emarginate B, latter forming a separate D (Figures 103-105); a small lamina (m) present at base of solenomere on dorsal side.
Gonopods (Figures 29-31, 109-114) complex, much as in N. hsientienensis, but lamella l larger and carrying a smooth to denticulate margin in distal part, not divided into two parts, end of sph divided into three distinct lobes: a denticulate A, and rugulose B and C.

Etymology
To emphasize the particular tip of the epiproct.

Diagnosis
Differs from congeners by the larger size, combined with the rather well-developed paraterga; an axial line is evident from the collum to the tip of the epiproct, and the gonopod femorite is rather narrow basally (see below and key).

Diagnosis
Differs from congeners by the short antennae and epiproct, as well as in some other somatic and sexual characters (see below and key), with the tip of the gonotelopodite being supplied with four lobes.
Male legs 1 up to those of segment 13 with tarsal brushes (Figure 48), setation gradually thinning out toward telson, relatively modest after segment 14. Legs relatively short, about as long as midbody height in " (Figures 43, 92), but only two-thirds midbody height in R.
Gonopods (Figures 49-52, 121-126) complex, much as in N. caudatus, but femorite with several folds on lateral side, l carrying a smooth to denticulate margin from midway distally; sph with four apical lobes (A, an emarginate B forming a separate lobe D, and C).

Etymology
Honours Dr Wu Sheng-Hai, Taichung, Taiwan, who provided much material for the present study.

Remarks on distribution and ecology
The island of Taiwan, a part of the island-arc system along the western edge of the Pacific Ocean, lies between the Asian continent and the Philippine Sea basin. The present elevation of Taiwan began ca 4 million years ago as a result of the collision of the Philippine and continental Asian tectonic plates (Page and Suppe 1981;Hsü 1990). Taiwan has an oceanic subtropical climate, being crossed in its middle by the Tropic of Cancer. However, with approximately 30% of its area lying between 1000 and 3000 m a.s.l., and more than 200 peaks above 3000 m in elevation, the mountains in Taiwan encompass a climatic range from subtropical to subarctic (Hsieh and Shen 1944). The tropical and subtropical virgin forests of lowland areas (,1000 m a.s.l.) are dominated by numerous species of Ficus and Machilus, although large areas of land have been converted to agriculture and plantations. Within the mid-montane belt (1000-2500 m a.s.l.), temperate and warm-temperate broadleaved forests of Castanopsis and Quercus are widespread. These gradually give way to mixed montane coniferous forests of Pinus, Chamaecyparis, and Taiwania at higher elevations. The Tsuga-Picea forests that dominate the high altitudes of Taiwan (2500-3000 m a.s.l.) are slowly replaced by subalpine Abies woodlands toward the timber line, followed thereafter by dwarf bamboo stands of Yushania miitakayamensis above 3000 m. Alpine vegetation occurs above 3500 m, with a low scrub community of Juniperus squamata and rhododendrons, and a high herb community that is widespread in these barren, rocky areas.
The millipede Nedyopus hsientienensis occurs in both northern and southern Taiwan, more frequently in secondary forests dominated by Acacia confuse, but also in natural forests at altitudes lower than 750 m a.s.l. The species Nedyopus pectinatus inhabits secondary forests, bamboo plantations, and Ficus-Machilus woodlands, mainly at middle elevations (700-1700 m a. s.l.), in the mountains of northern and central Taiwan. In contrast, Nedyopus caudatus is widespread in central and southern Taiwan, ranging from low to middle altitudes (100-2100 m a.s.l.). It frequently occurs in plantations, such as bamboo or Cryptomeria japonica, as well as in virgin montane forests. Nedyopus latus has only been found in central Taiwan, mostly in secondary forests at middle elevations (1000-1700 m a. s.l.), whereas N. wui seems to prefer virgin forest, at middle elevations, but still somewhat higher, between 2000-2550 m a.s.l., in central and northeastern Taiwan. Such distributions show that, like the vast majority of Diplopoda, species of the genus Nedyopus are primarily forest-dwellers. In Taiwan at least, they tend to occur in mature primary stands in the mid-montane belt. Central Taiwan, the best-forested part of the island, appears to support most if not all of the Nedyopus species. This alone suggests a very high degree of endemicity.
In Taiwan, most of the species of Nedyopus can tolerate some degree of anthropogenic pressure, also living in secondary forests or plantations. Unsurprisingly though, these tendencies are more typical of widely distributed congeners, e.g. N. hsientienensis. In contrast, the most restricted mid-montane species, like N. latus and N. wui, tend to prefer natural forest.
Key to the Taiwanese species of Nedyopus