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

publication ID

https://doi.org/10.5852/ejt.2018.462

publication LSID

lsid:zoobank.org:pub:urn:lsid:zoobank.org:pub:60992A95-1F59-4407-9774-B8FC1545A8B4

persistent identifier

http://treatment.plazi.org/id/03A287AE-0D5A-224D-F789-ED22FCF15B34

treatment provided by

Plazi

scientific name

Nagaxytes spatula Srisonchai, Enghoff & Panha
status

gen. et sp. nov.

Nagaxytes spatula Srisonchai, Enghoff & Panha  gen. et sp. nov.

urn:lsid:zoobank.org:act:6B8E3EA4-8290-4EF4-A804-FCA28BE32863

Figs 22–26View Fig. 22View Fig. 23View Fig. 24View Fig. 25View Fig. 26

Diagnosis

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.

Etymology

The name is a Latin noun in apposition, referring to the spatulate lobe on the lamina lateralis.

Material examined

Holotype THAILAND: ♂, Tak Province, Mae Sot District, Chao Por Phawo Shrine , 16°46′19″ N, 98°41′11″ E, ca. 688 m a.s.l., 29 Aug. 2016, ASRU members leg. ( CUMZ-pxDGT00119).GoogleMaps 

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). 

Description

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–C View Figure ). 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. 23A View Figure ). 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. 23D View Figure ). 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–C View Figure ). 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.

PARATERGA ( Figs 23F–G View Figure , 24B View Figure ). Directed caudolaterad on body rings 2–18, elevated at ca. 50°–60° (male) 45°–50° (female), directed increasingly caudad on body ring 19.

TELSON ( Fig. 24C–G View Figure ). 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–J View Figure ). Cross-impressions shallow. Sternal lobe between male coxae 4 stout; base broad; tip deeply emarginate to incompletely bilobed.

GONOPODS ( Figs 25 View Figure , 26 View Figure ). 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 25D View Figure , 26C View Figure ); 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.

Remarks

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.

ZMUM

Zoological Museum, University of Amoy

NHMW

Naturhistorisches Museum, Wien

NHMUK

Natural History Museum, London

CUMZ

Chulalongkorn University Museum of Natural History