Nagaxytes spatula Srisonchai, Enghoff & Panha
Ruttapon Srisonchai, Henrik Enghoff, Natdanai Likhitrakarn & Somsak Panha, 2018, A revision of dragon millipedes II: the new genus Nagaxytes gen. nov., with the description of three new species (Diplopoda, Polydesmida, Paradoxosomatidae), European Journal of Taxonomy 462, pp. 1-44: 34-41
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|Nagaxytes spatula Srisonchai, Enghoff & Panha|
gen. et sp. nov.
Nagaxytes spatula Srisonchai, Enghoff & Panha gen. et sp. nov.
Metaterga 2–8 with two rows of spines (1+1 or 2+2 spines in anterior row, 2+2 spines in posterior row). Similar in this respect to N. erecta gen. et sp. nov., but differs by having: degree of elevation of paraterga higher; apical tubercles of epiproct inconspicuous; surface near lateral sulcus swollen as long ridge; lamina lateralis broad, with a long and conspicuous spatula-like lobe; lamina medialis very long, curved, apically hook-like; tip of solenomere terminating in two curved processes.
The name is a Latin noun in apposition, referring to the spatulate lobe on the lamina lateralis.
Paratypes THAILAND: 27 ♂♂, 19 ♀♀, same data as for holotype ( CUMZ-pxDGT00120-165); 1 ♂, 1 ♀, same data as for holotype (ZMUC 00040246) ; 1 ♂, 1 ♀, same data as for holotype ( ZMUMAbout ZMUM) ; 1 ♂, 1 ♀, same data as for holotype ( NHMWAbout NHMW) ; 1 ♂, 1 ♀, same data as for holotype ( NHMUKAbout NHMUK) .
Further specimens, not paratypes
THAILAND – Tak Province: Mae Sot District: 1 ♀, Chao Por Phawo Shrine GoogleMaps, 16°46′19″ N, 98°41′11″ E, ca. 688 m a.s.l., 29 Jun. 2015, ASRU members leg. ( CUMZAbout CUMZ); 1 ♂, 1 ♀, Wat Tham Inthanin GoogleMaps, 16°45′59″ N, 98°40′21″ E, 671 m a.s.l., 18 Oct. 2015, ASRU members leg. ( CUMZAbout CUMZ); 10 broken specs, Wat Pho Thi Khun ( Wat Huai Toey GoogleMaps), 16°45′42″ N, 98°38′49″ E, ca. 431 m a.s.l., 27 Jul. 2016, P. Pimvichai, P. Prasankok and N. Nantarat leg. ( CUMZAbout CUMZ); 3 ♂♂, 6 ♀♀, Wat Pho Thi Khun ( Wat Huai Toey GoogleMaps), 16°45′42″ N, 98°38′49″ E, ca. 431 m a.s.l., 29 Aug. 2016, ASRU members leg. ( CUMZAbout CUMZ). – Umphang District: 1 ♂, 1 ♂ (left gonopod lost), 4 ♀♀, Tham Takhobi ( Takhobi Cave GoogleMaps), 16°03′15″ N, 98°49′14″ E, ca. 510 m a.s.l., 5 Jul. 2009, ASRU members leg. ( CUMZAbout CUMZ); 1 ♂, 1 ♀, Tham Takhobi ( Takhobi Cave GoogleMaps), 16°03′15″ N, 98°49′14″ E, ca. 510 m a.s.l., 1 Jul. 2015, ASRU members leg. ( CUMZAbout CUMZ); 4 ♂♂, 6 ♀♀, many broken specs, Doi Hua Mod GoogleMaps, 15°57′30″ N, 98°51′13″ E, ca. 894 m a.s.l., 5 Jul. 2009, ASRU members leg. ( CUMZAbout CUMZ); 1 ♂, 1 ♀, 1 juvenile, Doi Hua Mod GoogleMaps, 15°57′30″ N, 98°51′13″ E, ca. 894 m a.s.l., 1 Jul. 2015, ASRU members leg. (CUMZ).
SIZE. Length 22–26 mm (male), 24–28 mm (female); width of midbody metazona ca. 2.0 mm (male), 2.8 mm (female). Width of head <collum = body ring 2 = 3 = 4 <5–17, thereafter body gradually tapering towards telson.
COLOUR ( Fig. 22A–CView Fig. 22). Specimens in life with body usually reddish brown (some specimens brown); prozona, metaterga, surface below paraterga and sterna reddish brown; antennae brown to dark brown (except whitish distal part of antennomere 7 and antennomere 8); head, paraterga, epiproct and leg brown; a few basal podomeres pale brown. Colour in alcohol: after 3–10 years changed to pale brown; head, antennae, collum, metaterga, surface below paraterga, sterna, epiproct, legs pale brown or whitish brown; paraterga brownish white.
COLLUM ( Fig. 23AView Fig. 23). With three transverse rows of setiferous tubercles and spines, 3+3 tubercles in anterior row, 1+1 tubercles in intermediate row and 2+2 spines in posterior row; paraterga of collum long and broad, elevated at ca. 25°–35° (male) 20°–30° (female), directed caudolaterad, with two conspicuous notches at lateral margin.
ANTENNAE ( Fig. 23DView Fig. 23). Very long and slender, reaching to body ring 6 or 7 (male) and 5 or 6 (female) when stretched dorsally.
TEGUMENT. Quite dull. Stricture between prozona and metazona quite deep, wide.
METATERGA ( Fig. 23A–CView Fig. 23). Male – metaterga 2–8 with 2(1)+2(1) anterior spines and 2+2 posterior spines (anterior spines small and sometimes inconspicuous; posterior spines longer and larger than anterior ones; lateral spines of posterior row very long); metaterga 9–19 with?1+?1 anterior small tubercles and 2+2 posterior spines (lateral spines of posterior row very long). Female – metaterga 2–10 with 2+2 anterior spines and 2+2 posterior spines (posterior spines longer and larger than anterior ones; lateral spines of posterior row very long); metaterga 11–18 with 1+1 anterior spines and 2+2 posterior spines (lateral spines of posterior row very long); metatergum 19 with?1+?1 anterior small tubercles and 2+2 posterior spines.
PLEUROSTERNAL CARINAE. On body ring 2 long, crest-like; on ring 3 long ridges; on ring 4 small ridges; thereafter missing.
TELSON ( Fig. 24C–GView Fig. 24). Epiproct quite short; tip subtruncate; lateral setiferous tubercles conspicuous, long, digitiform; apical tubercles inconspicuous. Hypoproct subtriangular, short and broad; caudal margin round, with conspicuous setiferous tubercles.
STERNA ( Fig. 24H–JView Fig. 24). Cross-impressions shallow. Sternal lobe between male coxae 4 stout; base broad; tip deeply emarginate to incompletely bilobed.
GONOPODS ( Figs 25View Fig. 25, 26View Fig. 26). Coxa shorter than femur. Cannula quite short and stout. Telopodite quite short and stout. Prefemoral part subequal in length to femur. Femur quite stout, slightly enlarged distad. Mesal sulcus conspicuous, deep, wide; lateral sulcus quite shallow and wide, surface near lateral sulcus swollen as long ridge. Postfemoral part conspicuous, wide, laterally demarcated from femur by a long ridge. Solenophore well-developed: lamina lateralis broad; with a long, flattened, conspicuous spatulate lobe, apically round, directed anteriad ( Figs 25DView Fig. 25, 26CView Fig. 26); lamina medialis very long; curved; apically hooklike. Solenomere long, tip terminating in two curved processes.
Distribution and habitat
Known only from Tak Province. Almost all specimens were seen crawling on rocks, some on leaf litter in limestone habitats. Some juveniles were collected from the leaf litter (probably in moulting chambers). In the field, the specimens blended perfectly with brown rocks and leaf litter.
The type locality for this species is situated beside road no. 12 (Tak –Mae Sot) near Khun Phawo National Park. We noticed that the forest beside the road is being destroyed for road construction, some parts of the limestone forest are being cut down.
For the time being, only five recorded locations are reported in the quite narrow distribution range of this species. After several intensive surveys we consider N. spatula gen. et sp. nov. to be endemic to Tak Province, Thailand.
We divide this species into two main populations, each restricted to a separate limestone areas:
– North populations: Chao Por Phawo Shrine, Wat Tham Inthanin and Wat Pho Thi Khun (Wat Huai Toey).
– South populations: Tham Takhobi (Takhobi Cave) and Doi Hua Mod.
Specimens of the North populations (24–26 mm in male, 26–28 mm in female) seem to be longer than those of the South populations (22–24 mm in male, 24–25 mm in female). However, other morphological characteristics, especially gonopod characters, are identical.
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