Nagaxytes gracilis Srisonchai, Enghoff & Panha 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: 18-41

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/A6CF5E48-B6AF-4FBD-A02D-D07E4DCDD605

taxon LSID

lsid:zoobank.org:act:A6CF5E48-B6AF-4FBD-A02D-D07E4DCDD605

treatment provided by

Plazi

scientific name

Nagaxytes gracilis Srisonchai, Enghoff & Panha Nagaxytes spatula Srisonchai, Enghoff & Panha
status

gen. et sp. nov.

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

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Figs 3 View Figure , 11–16View Fig. 11View Fig. 12View Fig. 13View Fig. 14View Fig. 15View Fig. 16

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. spatula  gen. et sp. nov. but differs by having: degree of elevation of paraterga lower; apical tubercles of epiproct conspicuous; surface near lateral sulcus without ridge (not swollen); lamina lateralis erect, long, thick, digitiform, tip round and directed anteriad; lamina medialis very long, apically fringed.

Etymology

The name is a Latin adjective and refers to the erect lamina lateralis of the gonopod telopodite.

Material examined

Holotype THAILAND: ♂, Kanchanaburi Province, Thong Pha Phum District, Phuphrai Thannam Resort , 14°44′0.6″ N, 98°38′36″ E, ca. 112 m a.s.l., 17 Aug. 2016, ASRU members leg. (CUMZ-pxDGT00001).GoogleMaps 

Paratypes THAILAND: 52 ♂♂, 36 ♀♀, same data as for holotype ( CUMZ-pxDGT00002-89);  1 ♂, 1 ♀, same data as for holotype ( ZMUC 00040244View Materials)  ; 1 ♂, 1 ♀, same data as for holotype ( ZMUMAbout ZMUM)  ; 1 ♂, 1 ♀, same data as for holotype (NHMW)  ; 1 ♂, 1 ♀, same data as for holotype (NHMUK)  .

Further specimens, not paratypes

THAILAND – Kanchanaburi Province: Thong Pha Phum District : 1 ♂ (gonopods lost), 4 ♀♀, Vajiralongkorn Dam, 28 Aug. 2011, ASRU members leg. ( CUMZAbout CUMZ);GoogleMaps  2 ♂♂, 2 ♀♀, Ban Nong Bang (near Wat Pha Sukit Suwannaket), 14°34′31″ N, 98°49′04″ E, ca. 151 m a.s.l., 12 Oct. 2015, ASRU members leg. (CUMZ)GoogleMaps  ; 4 ♂♂, 3 ♀♀, Wat Pak Lam Pilock, 14°37′41″ N, 98°34′26″ E, ca. 257 m a.s.l., 11 Oct. 2015, ASRU members leg. (CUMZ);  1 ♂, 3 ♀♀, Wat Tha Kha-nun, 14°44′36″ N, 98°38′18″ E, ca. 114 m a.s.l., 24 Jul. 2016, P. Pimvichai, P. Prasankok and N. Nantarat leg. (CUMZ);  12 ♂♂, 21 ♀♀, Wat Tha Kha-nun, 14°44′36″ N, 98°38′18″ E, ca. 114 m a.s.l., 16 Aug. 2016, ASRU members leg. ( CUMZAbout CUMZ);  20 ♂♂, 46 ♀♀, Prang Ka Sri Temple (Wat Prang Ka Sri), 14°39′05″ N, 98°40′08″ E, ca. 106 m a.s.l., 15 Aug. 2016, leg. ASRU members ( CUMZAbout CUMZ).  Sai Yok District   GoogleMaps: 1 broken ♂ (gonopods lost), Daowadueng Cave, 14°28´23″ N, 98°50´04″ E, ca. 133 m a.s.l., 8 Sep. 2008, ASRU members leg. (CUMZ);  4 ♂♂, 5 broken ♂♂, 1 broken ♂ (right gonopod lost), 2 ♂♂ (left gonopod lost), 1 ♂ (remaining rings 1–8), 10 ♀♀, 1 juvenile, Daowadueng Cave, 14°28´23″ N, 98°50´04″ E, ca. 133 m a.s.l., 11 Jul. 2009, ASRU members leg. (CUMZ);  5 ♂♂, 4 ♀♀, Daowadueng Cave, 14°28´23″ N, 98°50´04″ E, ca. 133 m a.s.l., 12 Oct. 2015, ASRU members leg. (CUMZ);  6 ♂♂, 2 ♀♀, Daowadueng Cave, 14°28´23″ N, 98°50´04″ E, ca. 133 m a.s.l., 15 Aug. 2016, ASRU members leg. (CUMZ);  6 ♂♂, 2 ♀♀, Wat Sunantha Wanaram, 14°32´11″ N, 98°49´51″ E, ca. 161 m a.s.l., 17 Aug. 2016, ASRU members leg. (CUMZ). 

Description

SIZE. Length 32–36 mm (male), 36–38 mm (female); width of midbody metazona ca. 2.4 mm (male), 3.4 mm (female). Width of head <collum <body ring 2 = 3 <4 <5–17, thereafter body gradually tapering towards telson.

COLOUR ( Figs 11 View Figure , 12A–C View Figure ). Specimens in life falling into two colour morphs: Reddish brown morph – body reddish brown; paraterga pinkish red; collum, metaterga and epiproct reddish brown; head, antennae (except whitish distal part of antennomere 7 and antennomere 8), prozona, surface below paraterga, sterna and legs brown; a few basal podomeres whitish brown. Brown morph – body brown; paraterga pinkish red; head, antennae (except whitish distal part of antennomere 7 and antennomere 8), collum, prozona, metaterga, epiproct and legs brown; paraterga and sterna pale brown; surface below paraterga brown or dark brown; a few basal podomeres whitish 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. 13A 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. 40°–45° (male) 35°–40° (female), directed caudolaterad, with two conspicuous notches at lateral margin.

ANTENNAE ( Fig. 13D View Figure ). Moderately long and slender, reaching to body ring 5 or 6 (male) and 4 or 5 (female) when stretched dorsally.

TEGUMENT. Quite dull. Stricture between prozona and metazona shallow, wide.

METATERGA ( Fig. 13A–C View Figure ). With two transverse rows of cones and spines; metaterga 2–15 with 2+2 anterior spines and 2+2 posterior spines (posterior spines longer and thicker than anterior ones; lateral spines of posterior row very long); metaterga 16–18 with 2+2 anterior cones/spines and 2+2 posterior cones/spines (brown morph – anterior cones/spines inconspicuous; lateral spines of posterior row very long); metatergum 19 with 1+1 anterior small tubercles/cones and 2+2 posterior spines (brown morph – anterior tubercles/cones poorly developed).

PLEUROSTERNAL CARINAE. On body ring 2 long, crest-like; on ring 3 long ridges; on ring 4 small ridges; thereafter missing.

PARATERGA ( Figs 13F–G View Figure , 14B View Figure ). Directed caudolaterad on body rings 2–17, elevated at ca. 60°–70° (male) 50°–60° (female), directed increasingly caudad on body rings 18–19.

TELSON ( Fig. 14C–G View Figure ). Epiproct quite short; tip usually subtruncate (in some specimens slightly emarginate); lateral setiferous tubercles conspicuous, long, digitiform; apical tubercles conspicuous. Hypoproct usually subtriangular (in some specimens subtrapeziform); caudal margin subtriangular or round, with conspicuous setiferous tubercles.

STERNA ( Fig. 14H–J View Figure ). Cross-impressions quite deep. Sternal lobe between male coxae 4 subtrapeziform, stout; base broad; tip emarginate.

GONOPODS ( Figs 15 View Figure , 16 View Figure ). Coxa subequal in length to femur. Cannula long and slender. Telopodite quite long and slender. Prefemoral part ca. half as long as femur. Femur quite long and slender, slightly enlarged distad. Mesal sulcus conspicuous, deep, wide; lateral sulcus quite deep and wide. Postfemoral part conspicuous, short. Solenophore well-developed: lamina lateralis erect, long, thick, digitiform; tip round, directed anteriad: lamina medialis very long; apically fringed with several small spines; tip directed mesad. Solenomere long and slender, tip directed anterolateriad.

Distribution and habitat

Nagaxytes erecta  gen. et sp. nov. is known only from Kanchanaburi Province, Thailand. All specimens were collected from limestone habitats during the rainy season (July–October). Lots of specimens were usually found near human areas, where some habitats were being destroyed for construction of a temple or bureau of monks.

At Daowadueng Cave, the new species lives syntopically with N. gracilis  gen. et sp. nov. and Desmoxytes purpurosea Enghoff, Sutcharit & Panha, 2007  , in the same habitat. Desmoxytes planata  was also found near the habitat of the new species at Phuphrai Thannam Resort and Wat Tha Kha-nun. We assume that D. planata  occurs in a different microhabitat because the areas where we collected it are very strongly influenced by humans, and all specimens were seen crawling on statues and concrete.

We have only found N. erecta  gen. et sp. nov. in a narrow area (100 km 2) along the huge limestone mountain range in Sai Yok and Thong Pha Phum Districts. Therefore, we regard this species as endemic for the Thai fauna.

Remarks

There is a considerable variation in the live colouration; two colour morphs can be distinguished – brownish red and brown. All specimens from Ban Nong Bang (near Wat Pha Sukit Suwannaket) show a brownish red colour whereas specimens from the remaining localities exhibit a brown colour (except at Daowadueng Cave: both reddish brown and brown colour morphs occur in the same place, even the same habitat). A further morphological difference between these two colour morphs concerns the size of cones/spines (anterior row) on metaterga 16–19: conspicuous in the reddish brown colour morph, inconspicuous in the brown morph. However, the gonopod characters are virtually identical. A similar phenomenon is also found in Desmoxytes cervina  in which two colour morphs share identical gonopod characters ( Srisonchai et al. 2018). Therefore, we regard the differences in colour as interpopulational variation. An intrapopulational variation was also found in the:

– tip of epiproct: in some specimens subtruncate, in others slightly emarginate.

– shape of hypoproct: in some individuals subtriangular, in others subtrapeziform. Some specimens of this species are infested by engorged mites (possibly of the genus Leptus) ( Fig. 12C View Figure ), as also found on D. cervina  by Srisonchai et al. (2018) and N. acantherpestes  gen. et comb. nov. as mentioned above.

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

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Figs 1 View Figure , 4 View Figure , 5 View Figure , 17–21View Fig. 17View Fig. 18View Fig. 19View Fig. 20View Fig. 21

Diagnosis

Metaterga 4–19 with one row of 2+2 posterior spines (anterior row absent). Similar in this respect to N. acantherpestes  gen. et comb. nov., but differs from this species by having paraterga longer; degree of elevation of paraterga higher; sternal lobe between male coxae 4 incompletely bilobed; lamina lateralis long, lamella-like, thin, slender, tip round and directed ventrad.

Etymology

The name is a Latin adjective, referring to the slender lamina lateralis of the gonopod telopodite.

Material examined

Holotype THAILAND: ♂, Kanchanaburi Province, Sai Yok District, Daowadueng Cave , 14°28′23″ N, 98°50′04″ E, ca. 133 m a.s.l., 15 Aug. 2016, ASRU members leg. ( CUMZ-pxDGT00090).GoogleMaps 

Paratypes THAILAND: 7 ♂♂, 21 ♀♀, same data as for holotype ( CUMZ-pxDGT00091-118);  1 ♂, 1 ♀, same data as for holotype (ZMUC 00040245). 

Further specimens, not paratypes

THAILAND – Kanchanaburi Province, Sai Yok District   GoogleMaps: 1 ♂, 1 broken ♂, 1 broken ♂ (right gonopod lost), 5 ♀♀, Daowadueng Cave, 14°28′23″ N, 98°50′04″ E, ca. 133 m a.s.l., 8 Sep. 2008, ASRU members leg. (CUMZ);  2 ♂♂, 6 ♀♀, Daowadueng Cave, 14°28′23″ N, 98°50′04″ E, ca. 133 m a.s.l., 11 Jul. 2009, ASRU members leg. ( CUMZAbout CUMZ);  2 ♂♂, Daowadueng Cave   GoogleMaps, 14°28′23″ N, 98°50′4″ E, ca. 133 m a.s.l., 12 Oct. 2015, ASRU members leg. (CUMZ);  8 ♂♂, 21 ♀♀, 1 broken ♂, 1 ♂ (right gonopod lost), 1 ♂ fragment (gonopods lost), Wat Tham Phrom Lok Khao Yai, 14°12′15″ N, 99°07′57″ E, ca. 122 m a.s.l., 9 Jul. 2009, ASRU members leg. ( CUMZAbout CUMZ);  1 ♂, Wat Tham Phrom Lok Khao   GoogleMaps Yai, 14°12′15″ N, 99°07′57″ E, ca. 122 m a.s.l., 15 Aug. 2016, ASRU members leg. ( CUMZAbout CUMZ);  1 ♂, Kra Sae Cave   GoogleMaps, 14°06′05″ N, 99°10′09″ E, ca. 79 m a.s.l., 10 Dec. 2006, ASRU members leg. (CUMZ);  3 ♂♂, 3 broken ♂♂, 1 ♂ (right gonopod lost), 5 ♀♀, Hellfire Pass, 14°21′20″ N, 98°57′09″ E, ca. 216 m a.s.l., 29 Aug. 2011, ASRU members leg. (CUMZ);  2 ♂♂, 2 ♀♀, Hellfire Pass, 14°21′20″ N, 98°57′09″ E, ca. 216 m a.s.l., Aug. 2014, ASRU members leg. (CUMZ);  1 ♂, 1 ♀, Ban Thung Kang Yang, 14°24′17″ N, 98°55′04″ E, ca. 263 m a.s.l., 15 Aug. 2016, ASRU members leg. (CUMZ);  4 ♂♂, 5 ♀♀, Wat Sunantha Wanaram, 14°32′11″ N, 98°49′51″ E, ca. 161 m a.s.l., 17 Aug. 2016, ASRU members leg. (CUMZ);  7 ♂♂, 6 ♀♀, Wat Phuttha Vimooddhi Wanaram (Wat Tham Phu Mood), 14°18′07″ N, 98°59′27″ E, ca. 213 m a.s.l., 17 Aug. 2016, ASRU members leg. (CUMZ). 

Description

SIZE. Length 30–33 mm (male), 35–38 mm (female); width of midbody metazona ca. 2.2 mm (male), 3.1 mm (female). Width of head <collum <body ring 2 = 3 = 4 <5–17, thereafter body gradually tapering towards telson.

COLOUR ( Fig. 17A–B View Figure ). Specimens in life with body pinkish brown; paraterga vivid pink or reddish pink; collum, prozona, metaterga, surface below paraterga pinkish brown; head, antennae (except whitish distal part of antennomere 7 and antennomere 8) sterna and legs brown; a few basal podomeres whitish brown; epiproct pink. Colour in alcohol: after 3–9 years changed to pale brown; head, collum, metaterga, surface below paraterga, sterna, epiproct pale brown or whitish brown; paraterga brownish white.

COLLUM ( Fig. 18A View Figure ). With three transverse rows of setae/tubercles and spines, 3+3 setae/tubercles in anterior row, 1+1 setae/tubercles in intermediate row (tubercles small) and 2+2 spines in posterior row; paraterga of collum long and broad, elevated at ca. 40°–45° (male) 35°–40° (female), directed caudolaterad, with 2 conspicuous notches at lateral margin.

ANTENNAE ( Fig. 18D View Figure ). Moderately long and slender, reaching to body ring 5 or 6 (male) and 4 or 5 (female) when stretched dorsally.

TEGUMENT. Quite shiny. Stricture between prozona and metazona shallow, wide.

METATERGA ( Fig. 18A–C View Figure ). Metatergum 2 with 1(2)+1(2) anterior tubercles/cones and 2+2 posterior spines; metatergum 3 with 1+1 anterior tubercles (inconspicuous) and 2+2 posterior spines; metaterga 4–19 with 2+2 posterior spines (anterior row absent; lateral spines of posterior row in all rings very long, longer than mesal ones).

PLEUROSTERNAL CARINAE. On body ring 2 long, crest-like; on body rings 3 and 4 small ridges; thereafter missing.

PARATERGA ( Figs 18F–G View Figure , 19B View Figure ). Directed caudolaterad on body rings 2–18, elevated at ca. 70° (male) 60°–70° (female), directed increasingly caudad on body ring 19; notch near the tip at lateral margin of body rings 5–7, 9, 10, 12, 13, 15–18 absent on some rings in some specimens.

TELSON ( Fig. 19C–G View Figure ). Epiproct quite short; tip usually subtruncate (in some specimens slightly emarginate); lateral setiferous tubercles conspicuous, long, digitiform; apical tubercles conspicuous. Hypoproct subtriangular; caudal margin subtriangular, with inconspicuous setiferous tubercles.

STERNA ( Fig. 19H–J View Figure ). Cross-impressions quite deep. Sternal lobe between male coxae 4 incompletely bilobed; base broad; tip deeply emarginate; surface near pores swollen.

GONOPODS ( Figs 4–5View Fig. 4View Fig. 5, 20–21View Fig. 20View Fig. 21). Coxa subequal in length to femur. Cannula long and slender. Telopodite quite long and slender. Prefemoral part ca. half as long as femur. Femur long and slender, slightly enlarged distally. Mesal sulcus conspicuous, deep, wide; lateral sulcus quite deep and very wide. Postfemoral part conspicuous, short. Solenophore well-developed: lamina lateralis long, lamellalike, thin, slender; tip round, directed ventrad: lamina medialis very long; slightly enlarged distally; apically fringed with several small spines; tip directed mesoventrad. Solenomere long and slender, tip directed ventrad.

Distribution and habitat

Nagaxytes gracilis  gen. et sp. nov. is known only from Sai Yok District, Kanchanaburi Province. All specimens were collected on humid rocks, superficial tree roots and litter in limestone habitats. It lives in the same habitat with D. purpurosea  , D. golovatchi Srisonchai, Enghoff & Panha, 2018  and N. erecta  gen. et sp. nov. (q.v.). The new species occurs in a narrow distribution area along the huge limestone range which is entirely contained within Sai Yok District. We thus consider this species to be endemic to Kanchanaburi Province, Thailand.

Remarks

The vivid pink paraterga are probably aposematic. Nagaxytes gracilis  gen. et sp. nov. was noticeable in the field by the contrast of its bright pink colour to brown rocks.

There is a variability in the tip of the epiproct: in some specimens subtruncate, in others slightly emarginate.

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

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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.

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

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Figs 1 View Figure , 4 View Figure , 5 View Figure , 17–21View Fig. 17View Fig. 18View Fig. 19View Fig. 20View Fig. 21

Diagnosis

Metaterga 4–19 with one row of 2+2 posterior spines (anterior row absent). Similar in this respect to N. acantherpestes  gen. et comb. nov., but differs from this species by having paraterga longer; degree of elevation of paraterga higher; sternal lobe between male coxae 4 incompletely bilobed; lamina lateralis long, lamella-like, thin, slender, tip round and directed ventrad.

Etymology

The name is a Latin adjective, referring to the slender lamina lateralis of the gonopod telopodite.

Material examined

Holotype THAILAND: ♂, Kanchanaburi Province, Sai Yok District, Daowadueng Cave , 14°28′23″ N, 98°50′04″ E, ca. 133 m a.s.l., 15 Aug. 2016, ASRU members leg. ( CUMZ-pxDGT00090).GoogleMaps 

Paratypes THAILAND: 7 ♂♂, 21 ♀♀, same data as for holotype ( CUMZ-pxDGT00091-118);  1 ♂, 1 ♀, same data as for holotype (ZMUC 00040245). 

Further specimens, not paratypes

THAILAND – Kanchanaburi Province, Sai Yok District   GoogleMaps: 1 ♂, 1 broken ♂, 1 broken ♂ (right gonopod lost), 5 ♀♀, Daowadueng Cave, 14°28′23″ N, 98°50′04″ E, ca. 133 m a.s.l., 8 Sep. 2008, ASRU members leg. (CUMZ);  2 ♂♂, 6 ♀♀, Daowadueng Cave, 14°28′23″ N, 98°50′04″ E, ca. 133 m a.s.l., 11 Jul. 2009, ASRU members leg. ( CUMZAbout CUMZ);  2 ♂♂, Daowadueng Cave   GoogleMaps, 14°28′23″ N, 98°50′4″ E, ca. 133 m a.s.l., 12 Oct. 2015, ASRU members leg. (CUMZ);  8 ♂♂, 21 ♀♀, 1 broken ♂, 1 ♂ (right gonopod lost), 1 ♂ fragment (gonopods lost), Wat Tham Phrom Lok Khao Yai, 14°12′15″ N, 99°07′57″ E, ca. 122 m a.s.l., 9 Jul. 2009, ASRU members leg. ( CUMZAbout CUMZ);  1 ♂, Wat Tham Phrom Lok Khao   GoogleMaps Yai, 14°12′15″ N, 99°07′57″ E, ca. 122 m a.s.l., 15 Aug. 2016, ASRU members leg. ( CUMZAbout CUMZ);  1 ♂, Kra Sae Cave   GoogleMaps, 14°06′05″ N, 99°10′09″ E, ca. 79 m a.s.l., 10 Dec. 2006, ASRU members leg. (CUMZ);  3 ♂♂, 3 broken ♂♂, 1 ♂ (right gonopod lost), 5 ♀♀, Hellfire Pass, 14°21′20″ N, 98°57′09″ E, ca. 216 m a.s.l., 29 Aug. 2011, ASRU members leg. (CUMZ);  2 ♂♂, 2 ♀♀, Hellfire Pass, 14°21′20″ N, 98°57′09″ E, ca. 216 m a.s.l., Aug. 2014, ASRU members leg. (CUMZ);  1 ♂, 1 ♀, Ban Thung Kang Yang, 14°24′17″ N, 98°55′04″ E, ca. 263 m a.s.l., 15 Aug. 2016, ASRU members leg. (CUMZ);  4 ♂♂, 5 ♀♀, Wat Sunantha Wanaram, 14°32′11″ N, 98°49′51″ E, ca. 161 m a.s.l., 17 Aug. 2016, ASRU members leg. (CUMZ);  7 ♂♂, 6 ♀♀, Wat Phuttha Vimooddhi Wanaram (Wat Tham Phu Mood), 14°18′07″ N, 98°59′27″ E, ca. 213 m a.s.l., 17 Aug. 2016, ASRU members leg. (CUMZ). 

Description

SIZE. Length 30–33 mm (male), 35–38 mm (female); width of midbody metazona ca. 2.2 mm (male), 3.1 mm (female). Width of head <collum <body ring 2 = 3 = 4 <5–17, thereafter body gradually tapering towards telson.

COLOUR ( Fig. 17A–B View Figure ). Specimens in life with body pinkish brown; paraterga vivid pink or reddish pink; collum, prozona, metaterga, surface below paraterga pinkish brown; head, antennae (except whitish distal part of antennomere 7 and antennomere 8) sterna and legs brown; a few basal podomeres whitish brown; epiproct pink. Colour in alcohol: after 3–9 years changed to pale brown; head, collum, metaterga, surface below paraterga, sterna, epiproct pale brown or whitish brown; paraterga brownish white.

COLLUM ( Fig. 18A View Figure ). With three transverse rows of setae/tubercles and spines, 3+3 setae/tubercles in anterior row, 1+1 setae/tubercles in intermediate row (tubercles small) and 2+2 spines in posterior row; paraterga of collum long and broad, elevated at ca. 40°–45° (male) 35°–40° (female), directed caudolaterad, with 2 conspicuous notches at lateral margin.

ANTENNAE ( Fig. 18D View Figure ). Moderately long and slender, reaching to body ring 5 or 6 (male) and 4 or 5 (female) when stretched dorsally.

TEGUMENT. Quite shiny. Stricture between prozona and metazona shallow, wide.

METATERGA ( Fig. 18A–C View Figure ). Metatergum 2 with 1(2)+1(2) anterior tubercles/cones and 2+2 posterior spines; metatergum 3 with 1+1 anterior tubercles (inconspicuous) and 2+2 posterior spines; metaterga 4–19 with 2+2 posterior spines (anterior row absent; lateral spines of posterior row in all rings very long, longer than mesal ones).

PLEUROSTERNAL CARINAE. On body ring 2 long, crest-like; on body rings 3 and 4 small ridges; thereafter missing.

PARATERGA ( Figs 18F–G View Figure , 19B View Figure ). Directed caudolaterad on body rings 2–18, elevated at ca. 70° (male) 60°–70° (female), directed increasingly caudad on body ring 19; notch near the tip at lateral margin of body rings 5–7, 9, 10, 12, 13, 15–18 absent on some rings in some specimens.

TELSON ( Fig. 19C–G View Figure ). Epiproct quite short; tip usually subtruncate (in some specimens slightly emarginate); lateral setiferous tubercles conspicuous, long, digitiform; apical tubercles conspicuous. Hypoproct subtriangular; caudal margin subtriangular, with inconspicuous setiferous tubercles.

STERNA ( Fig. 19H–J View Figure ). Cross-impressions quite deep. Sternal lobe between male coxae 4 incompletely bilobed; base broad; tip deeply emarginate; surface near pores swollen.

GONOPODS ( Figs 4–5View Fig. 4View Fig. 5, 20–21View Fig. 20View Fig. 21). Coxa subequal in length to femur. Cannula long and slender. Telopodite quite long and slender. Prefemoral part ca. half as long as femur. Femur long and slender, slightly enlarged distally. Mesal sulcus conspicuous, deep, wide; lateral sulcus quite deep and very wide. Postfemoral part conspicuous, short. Solenophore well-developed: lamina lateralis long, lamellalike, thin, slender; tip round, directed ventrad: lamina medialis very long; slightly enlarged distally; apically fringed with several small spines; tip directed mesoventrad. Solenomere long and slender, tip directed ventrad.

Distribution and habitat

Nagaxytes gracilis  gen. et sp. nov. is known only from Sai Yok District, Kanchanaburi Province. All specimens were collected on humid rocks, superficial tree roots and litter in limestone habitats. It lives in the same habitat with D. purpurosea  , D. golovatchi Srisonchai, Enghoff & Panha, 2018  and N. erecta  gen. et sp. nov. (q.v.). The new species occurs in a narrow distribution area along the huge limestone range which is entirely contained within Sai Yok District. We thus consider this species to be endemic to Kanchanaburi Province, Thailand.

Remarks

The vivid pink paraterga are probably aposematic. Nagaxytes gracilis  gen. et sp. nov. was noticeable in the field by the contrast of its bright pink colour to brown rocks.

There is a variability in the tip of the epiproct: in some specimens subtruncate, in others slightly emarginate.

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.

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

CUMZ

Chulalongkorn University Museum of Natural History

NHMW

Naturhistorisches Museum, Wien

NHMUK

Natural History Museum, London