ЗООЛОГИЧЕСКИЙ ЖУРНАЛ, 2015, том 94, № 9, с. 1023-1028
TWO NEW SPECIES OF THE MILLIPEDE ORDER POLYDESMIDA FROM SOUTHERN CHINA (DIPLOPODA)
© 2015 S. I. Golovatch
Severtsov Institute for Problems of Ecology and Evolution, Russian Academy of Sciences, Moscow 119071, Russia
e-mail: email@example.com Received February 8, 2015
Two new species of Polydesmida are described from China: Epanerchodus fuscus sp. n. (Polydesmidae), from Yunnan Province, and Riukiaria spatuliformis sp. n. (Xystodesmidae), from Sichuan Province. Both species are mainly distinguished from their congeners by highly characteristic colour patterns and, especially, gono-pod conformations. The former species shows nearly blackish middle regions of terga with contrasting light brown lateral parts of paraterga, coupled with a stout anchor-shaped process p1, a long spine-shaped p2, a long lamellar endomere and a missing exomere. The latter species demonstrates a clearly cingulate pattern of dark castaneous metazonae and light olive green prozonae, combined with a spatulate prefemoral process and a long, slender solenomere, the distal third subgeniculate.
Keywords: Polydesmida, Epanerchodus, Riukiaria, new species, Yunnan, Sichuan DOI: 10.7868/S004451341509010X
The Diplopoda, or millipedes, is the third largest class of terrestrial arthropods, following Insecta and Arachnida. Millipedes presently encompass about 12,000 described species from nearly 2000 genera, almost 150 families and 16 orders (Shear, 2011; Brewer et al., 2012). Most of the known millipede species and genera belong to the order Polydesmida (Brewer et al., 2012). Within the extratropical Polydesmida, two largely Holarctic families are the most diverse: Polydesmidae and Xystodesmidae.
In China, each of these families is represented by only a few genera. The most species-rich in Polydesmidae is Epanerchodus Attems, 1901, a genus dominating the entire diplopod fauna of East Asia. It contains nearly 80 species and ranges from Central Asia (Uzbekistan, Tajikistan, Afghanistan and northern Pakistan) in the west to the Russian Far East, Korea, Japan and Taiwan in the east, south to the Himalayas and southern China (Golovatch, 2014); many species, especially in Japan, are troglobites. At present, 17 unquestioned and several dubious species are known to occur in mainland China. Most have been keyed and are localized endemics (Golovatch, 2014, 2014b; Golovatch, Geoffroy, 2014).
The family Xystodesmidae is mainly represented in China by the speciose genus Riukiaria Attems 1938, which is especially diverse in southern Japan. Of its about 33 established species or subspecies, only seven, all keyed, inhabit mainland China (Golovatch, 2014a). These species range from the coast as far inland as Sichuan and Shaanxi provinces and, like Epanerchodus spp., nearly all are very local in distribution.
All the more interesting is the discovery in each genus of another new species from the mountains of southern China. Their descriptions are presented below.
The material reported below was taken by I. Be-lousov and I. Kabak (both St. Petersburg, Russia) during their field trip to China in 2014. The specimens remain stored in 75% alcohol and nearly all are deposited in the collection of the Zoological Museum, Moscow State University (ZMUM + entry number). One paratype is shared with the holdings of the Zoological Institute, Russian Academy of Sciences, St. Petersburg (ZIN), as indicated below.
Digital images of the specimens were taken in the laboratory and assembled using the Zerene Stacker software.
Epanerchodus fuscus Golovatch sp. n.
(Figs 1, 2)
Material. Holotype $ (ZMUM p2569), China, Yunnan Prov., NE of Lanping, SE of Xinshanchang, 3325 m a.s.l., 26°31'13" N, 99°28'47" E, gentle slope, broadleaved forest with glades near river valley, 18.06.2014, leg. I. Belousov & I. Kabak.
Description. Length ca 17 mm, width of middle pro- and metazonae 2.3 and 4.0 mm, respectively. Coloration of midtergal regions in alcohol blackish-brown, lateral parts of paraterga light brown, slightly marbled; legs, venter, epiproct and tip of antennae very light brown (Fig. 1).
Fig. 1. Epanerchodus fuscus sp. n., holotype: A — habitus, lateral view; B—D — anterior, middle and posterior parts ofbody, respectively, dorsal views. Pictures by K.V. Makarov, taken not to scale.
Body with 20 segments. Tegument mainly shining, texture delicately alveolate. Head densely pilose throughout, with squarish genae. Antennae rather long and only slightly clavate, antennomere 6 being highest (height measured from the lower to the higher edge) (Fig. 1A), reaching caudal margin of body segment 3 when stretched dorsally; antennomere 3 longest, ca 1.3 times longer than subequal antennomeres 2 and 4—6; 5th and 6th each with a small, compact, distodorsal group of bacilliform sensilla; antennomere 7 with a minute parabasal cone and a distal group of microscopic sensilla dorsally.
In width, head <§ collum < segment 2 < 3 < 4 < 5=15, thereafter body gradually tapering towards tel-son (Figs 1B, 1D). Paraterga strongly developed, mid-body pro- to metatergite ratio being ca 1:2.0; set high (at about upper % of midbody height), starting with collum, dorsum faintly convex; following paraterga mostly subhorizontal, all lying a little below dorsum,
drawn clearly forward only on metatergum 2 (Fig. 1B). Caudolateral corners of postcollum paraterga spini-form, pointed, from segment 6 drawn back increasingly well behind rear tergal margin, especially clearly so on segments 16—18 (Fig. 1D). All poreless segments with three, all pore-bearing ones with four, minute incisions at lateral margin. Front edges of metaterga slightly bordered and upturned, straight, usually forming a distinct shoulder. Pore formula normal, ozopores evident, dorsal, located in front of posteriormost marginal indentation. Metatergal sculpture typical, rather poorly developed, with three transverse rows of flat, setiferous, polygonal bosses, fore row being clearly obliterated and indistinct (Figs 1B—1D). Tergal setae very short, microscopic, simple, mostly abraded.
Stricture between pro- and metazonae wide, shallow and smooth. Limbus very thin, microdenticulate. Pleurosternal carinae small, oblique crests on segment 2, vestigial on segment 3, missing thereafter. Epiproct
tively; en — endomere, s — clivus, sg — seminal groove, pi andp2 — postfemoral processes. Scale bar (mm): A — 0.2 ; B, C — 0.5.
rather short, conical, pre-apical lateral papillae small, but evident (Fig. ID). Hypoproct subtrapeziform; caudal, paramedian, setiferous papillae large, well-separated.
Sterna without modifications, densely setose. Legs generally rather long and slender, likely to be somewhat incrassate in $ compared to Ç (Figs 1A, 2A), ca 1.6—1.7 times as long as midbody height; prefemora not inflated laterad; coxae, prefemora and femora be-
set ventrally with mostly bi- or trifid setae turning into short sphaerotrichomes on postfemora, tibiae and tarsi (Fig. 2A).
Gonopods (Figs 1F, 2B, 2C) with large, subquadrate coxae strongly fused medially at base and carrying two long setae ventrally. Telopodite stout, slightly bent caudolaterad, prefemoral (densely setose) portion comprising about half of length; seminal groove running mesally over most of its extent, only distally recurved laterobasad at base of endomere (en). The latter
lamellar, more laterally curved, high and indistinctly trifid apically. Seminal groove (sg) terminating in an evident accessory seminal chamber lying at bottom of a distinct, caudal, femoral cavity, with a hairy pulvillus marking sg orifice and located mesal to a long and low clivus (s). Two processes situated at base of en: a peculiar, stout, anchor-shaped pi adjacent to a slightly curved, clearly longer, spine-shaped p2.
Diagnosis. Using the available key to 13 mainland Chinese Epanerchodus spp. (Golovatch, 2014) and considering three more recently described species (Golovatch, 2014b; Golovatch, Geoffroy, 2014), E. fuscus sp. n. joins the few congeners in which the head is considerably narrower than the collum while the body is large (>14 mm long) and dark (brown to brown-blackish). Only E. fuscus sp. n. and E. yunnan-ensis Golovatch 2014, also from Yunnan Province,
share the slender, non-inflated $ prefemora, the absence of a gonopod exomere and the presence of two processes at the base of the endomere. Yet, in contrast to the new species, E. yunnanensis is larger (21—23 mm long), light brown, the paraterga are slightly upturned and gonopod process p1 is slender, not anchor-shaped.
Remark. E. fuscus sp. n. represents still another high-montane element in the millipede fauna of China, occurring well above 3,000 m a.s.l. in the mountains of Yunnan Province.
Name. To emphasize the prevailing fuscous, mostly blackish-brown coloration.
Riukiaria spatuliformis Golovatch sp. n.
(Figs 3, 4)
Material. Holotype tf (ZMUM p2570), China, Sichuan Prov., N of Luding City, N of Lanan, 2525 m a.s.l., 30°03'29" N, 102°14'0" E, edge of village, meadows altering with secondary shrubs, 18.06.2014,
leg. I. Belousov & I. Kabak. Paratypes: 1 $ (ZMUM
p2571), 1 $ (ZIN), same data, together with holotype.
D e s c rip t io n. Length of all types ca 23 mm, width of pro- and metazonae 3.5 and 5.5 mm, respectively. Coloration in alcohol generally castaneous brown with a vivid cingulate pattern of marbled brown metaterga and light olive green-yellow proterga, antennae, mountparts, venter, legs and epiproct tip. All margins of collum and following metaterga narrowly flavous, also light olive green-yellow (Figs 3A—3E). A narrow, light, grey, axial stripe visible all along dorsum through a translucent tegument.
Body with 20 segments. Tegument smooth and shining, only metaterga in places very faintly rugulose. Head (Fig. 3C) with lobed genae; two transverse, rather regular and very dense rows of setae just behind front margin of labrum, a few setae on frons, 1 + 1 setae betw
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