Nagaxytes erecta Srisonchai, Enghoff & Panha, 2018

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 : 18-27

publication ID	https://doi.org/ 10.5852/ejt.2018.462
publication LSID	urn:lsid:zoobank.org:pub:60992A95-1F59-4407-9774-B8FC1545A8B4
DOI	https://doi.org/10.5281/zenodo.5946408
persistent identifier	https://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 erecta Srisonchai, Enghoff & Panha
status	gen. et sp. nov.

Treatment

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

urn:lsid:zoobank.org:act:914BBC06-157C-419B-8B66-EBD18475B5BC

Figs 3 View Fig. 3 , 11–16 View Fig. 11 View Fig. 12 View Fig. 13 View Fig. 14 View Fig. 15 View 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 00040244 View Materials ) ; 1 ♂, 1 ♀, same data as for holotype ( 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. ( 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. ( 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 ( CUMZ). GoogleMaps – Sai Yok District : 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); GoogleMaps 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 Fig. 11 , 12A–C View Fig. 12 ). 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 Fig. 13 ). 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 Fig. 13 ). 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 Fig. 13 ). 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 Fig. 13 , 14B View Fig. 14 ). 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 Fig. 14 ). 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 Fig. 14 ). Cross-impressions quite deep. Sternal lobe between male coxae 4 subtrapeziform, stout; base broad; tip emarginate.

GONOPODS ( Figs 15 View Fig. 15 , 16 View Fig. 16 ). 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 Fig. 12 ), as also found on D. cervina by Srisonchai et al. (2018) and N. acantherpestes gen. et comb. nov. as mentioned above.