Hylomus was established as a monotypic genus by Cook and Loomis (1924), who were so impressed by the remarkable external features of the type species, H. draco Cook & Loomis, 1924, viz., the strongly elevated paraterga (like trees), that they placed the new species not only in a new genus but even in a new family, Hylomidae.

Jeekel (1964, 1968) maintained Hylomus as a valid genus, including only H. draco, and moved it into family Paradoxosomatidae, stating that the genus Pratinus Attems, 1937 (=Desmoxytes) was closely related to Hylomus.

Later, Jeekel (1980a) re-assessed the generic allocation of all members of Hylomus, Desmoxytes Chamberlin, 1923, Pratinus Attems, 1937, Prionopeltis Pocock, 1895 and Ceylonesmus Chamberlin, 1941, leading to the recognition of three genera: Hylomus, Desmoxytes (= Prionopeltis, Pratinus, Ceylonesmus) and Pteroxytes Jeekel, 1980. Jeekel (1980a) stated that the morphological characters of Hylomus showed clear differences from Desmoxytes and Pteroxytes (paranota antler-shaped and detail of gonopodal apex). The same author emphasised that his work was just a preliminary outline, and that “the discovery of new species … may considerably change the picture”.

Golovatch and Enghoff (1994) disagreed with Jeekel’s idea (1980a) to maintain Hylomus and Pteroxytes as separate genera. Based on new evidence from examination of old and new material, previous literature and the first cladistic analysis based on morphology, the authors synonymised Hylomus and Pteroxytes under Desmoxytes and assigned the genus to tribe Orthomorphini, of which they regarded Hylomini a synonym.

As mentioned above, our morphological analysis, as well as the initial molecular study, support recognition of Hylomus as a valid genus in agreement with Jeekel (1980a). We therefore consider Hylomus as a valid genus, separate from Desmoxytes. We further reallocate 33 species of Desmoxytes s.l. from China (19 species), Vietnam (ten species), Laos (three species) and Thailand (one species) to Hylomus (see Table 2).

Type species. Desmoxytes coniger Chamberlin, 1923 (MCZ, USA). This species was later synonymised with Desmoxytes planata by Jeekel (1980a).

(18).

– D. aurata sp. n.

– D. breviverpa Srisonchai, Enghoff & Panha, 2016

– D. cervina (Pocock, 1895)

– D. corythosaurus sp. n.

– D. delfae (Jeekel, 1964)

– D. des Srisonchai, Enghoff & Panha, 2016

– D. euros sp. n.

– D. flabella sp. n.

– D. golovatchi sp. n.

– D. octoconigera sp. n.

– D. perakensis sp. n.

– D. pinnasquali Srisonchai, Enghoff & Panha, 2016

– D. planata (Pocock, 1895) (= D. coniger Chamberlin, 1923, type species)

– D. purpurosea Enghoff, Sutcharit & Panha, 2007

– D. takensis Srisonchai, Enghoff & Panha, 2016

– D. taurina (Pocock, 1895)

– D. terae (Jeekel, 1964)

– D. waepyanensis sp. n.

Desmoxytes s.l. was reviewed by Golovatch and Enghoff (1994), and the diagnosis of the genus was treated in detail again by Golovatch et al. (2012). Here we propose a restricted diagnosis for Desmoxytes s.s. based on morphological characters (gonopod, tegument, paraterga, metaterga, sterna, femora, epiproct, hypoproct) which have been extracted from previous taxonomic works (Pocock 1895, Chamberlin 1923, 1941, Jeekel 1964, 1980a, Golovatch and Enghoff 1994, Enghoff et al. 2007, Srisonchai et al. 2016).

For DesmoxytessensuGolovatch and Enghoff (1994) we will retain the name “dragon millipede”, originally coined by Cook and Loomis (1924) for Hylomus draco. Golovatch et al. (2012) outlined the history of the name “dragon millipede” and further argued that Desmoxytes philippina Nguyen & Sierwald, 2010 (Philippine Isl.), and Desmoxytoides hasenpuschorum Mesibov, 2006 (Australia) have been wrongly assigned to Desmoxytes and “dragon millipedes”, respectively.

Desmoxytes s.s. differs from other genera of Orthomorphini by the combination of the following characters:

1. Gonopod suberect: solenophore strongly condensed; lamina lateralis developed, lobe-like, without process or spine; lamina medialis distinctly demarcated from lamina lateralis, bearing process and lobes.

2. Metaterga with 2 transverse rows of setiferous setae/ tubercles/ cones/ spines.

3. Paraterga wing-shaped, well-elevated.

4. Sternal cone between male coxae 4 present; subtrapeziform/ subquadrate/ subsemicircular/ incompletely bilobed.

5. Male femora 5 and 6 modified; swollen/humped (exception: D. terae without modification).

The description applies to adult males and females, except for the gonopods section and when “male” is specified (Figs 5, 6, 7, 8). The description hereunder is mainly based on illustrations of D. planata.

SIZE: Body length 16–35 mm (male) 20–38 mm (female), width ca. 1.7–2.5 mm (male) 2.0–3.6 mm (female); size varies between species, usually female wider and longer than male.

COLOUR: Most species in life with aposematic colouration: purplish pink, red, orange, brown, black, brownish black (piceous), brownish red (testaceous). Colour in alcohol: all specimens partly faded after one year’s preservation in alcohol; specimens kept in darkness faded more slowly.

HEAD (Figs 5C, 6A, B, I): Sparsely setose; vertex bare; labrum and genae sparsely setose; epicranial suture conspicuous as a brown or black stripe.

ANTENNAE (Fig. 5A–C): Often long and slender, rarely short, covered by delicate setation, usually reaching backwards to body ring 3–8 (male) and 3–6 (female) when stretched dorsally. Antennomere lengths 3 = 4 = 5 > 2 > 6 > 1 > 7 > 8.

COLLUM (Fig. 6A, C): With 1–3 transverse rows of setae/tubercles, the exact number in each row varying between species (sometimes lateral setae/tubercles of anterior row located nearly at the base of paraterga, on anterior margin). Paraterga wing-shaped, usually elevated at ca. 0°–30°.

TEGUMENT (Fig. 6A–E, G): Often shining, sometimes dull; collum and metaterga often microgranulate; surface below paraterga coarsely or finely microgranulate; prozona finely shagreened. Suture between prozona and metazona usually shallow, quite narrow.

METATERGA (Figs 5A, 6A, C, D, G): With 2 transverse rows of setae/tubercles/cones/spines, number in each row varying between species, lateral cones/spines of posterior row often longer and larger than inner and/or mesal ones. Suture (transverse sulcus) on metaterga present, usually conspicuous on body rings 5–17 in all species. Mid-dorsal (axial) line missing. Pleurosternal carinae forming complete, tooth-liked crests on ring 2, small ridges on ring 3, missing on remaining body rings.

PARATERGA (Figs 5A, B, D, 6A–E, G, H): Wing-shaped, well-elevated, directed caudolaterad. Callus and shoulder present, usually conspicuous, sometimes inconspicuous. Anterior margin with two distinct notches; on body rings 9, 10, 12, 13, 15–18 a tiny denticle present on lateral margin, near tip (but denticle virtually absent in some species). Elevation of paraterga in male usually higher than in female. Posterior edge concave. Tip pointed and sharp. Ozopore visible from above, round.

TELSON (Fig. 6F, G, N): Epiproct often flattened ventrally, tip often truncate or subtruncate, sometimes emarginate; lateral tubercles often conspicuous, sometimes inconspicuous; apical tubercles usually evident, sometimes indistinct, apically with two pairs of setae. Paraprocts convex. Hypoproct often subtrapeziform, sometimes subsemicircular, rarely subtriangular; caudal margin often round, sometimes emarginate, with two small setiferous tubercles.

STERNA (Figs 5E, 6K): Sparsely setose; cross-impressions faint, usually shallow, rarely quite deep. Sternal lobe between male coxae 4 usually subtrapeziform, subrectangular, subsemicircular or round, varying between species and sometimes varying between populations, usually with two pores on posterior side.

LEGS (Figs 5F, 6J, M): Very long and slender. Podomere lengths 3 = 6 > 5 > 2 = 4 > 1 > 7. Male femora 5 and 6 modified, often humped ventrally in middle part, sometimes swollen (exception: D. terae, without modification).

GONOPODS (Figs 6L, 7, 8): Coxa (cx) usually subequal in length to or longer than prefemur, with distoanterior group of seta. Prefemur (pfe) almost half or 2/3 as long as femur. Femur often long. Seminal groove (sg) running entirely on mesal surface of femur. Mesal sulcus (ms) conspicuous, deep; lateral sulcus (ls) conspicuous, usually deep, sometimes shallow. Postfemur shorter than femur, conspicuous. Solenophore (sph) variable between species: lamina lateralis (ll) swollen, sometimes with furrow(s) anterolaterally, sometimes with conspicuous ventral lobe (vll) or ventral ridge (vrl); lamina medialis (lm) variously species-specifically modified, consisting of one process (plm) and two lobes (distal lobe = dlm and broad lobe = blm, dlm and blm demarcated by indentation). Solenomere (sl) usually long, sometimes short.

From south China to Malaysia. Most species seem to be local endemics (only D. planata is dispersed, certainly by anthropochory, through mainland Southeast Asia and in many islands). Desmoxytes specimens were usually found by ASRU personnel in limestone habitats or on granitic mountains, and some were seen crawling on rocks or vegetation or tree branches (Figure 4).

Male (CUMZ), THAILAND, Surat Thani Province, Kanchanadit District, Khao Phanom Wang Cave, 9°05'27"N, 99°36'28"E, ca. 52 m a.s.l., 7 August 2015, leg. C. Sutcharit, R. Srisonchai, and ASRU members.

10 males, 7 females (CUMZ), same data as holotype. 17 males, 3 females (CUMZ), 1 male, 1 female (ZMUC), 1 male (ZMUM), 1 male (NHMW), 1 male (NHMUK), THAILAND, Surat Thani Province, Kanchanadit District, Wat Praphutthabart Sri Surat, 9°11'11"N, 99°34'47"E, ca. 19 m a.s.l., 6 December 2016, leg. S. Panha and ASRU members.

Further specimens, not paratypes, all from THAILAND, Surat Thani Province: 8 males, 18 females, 3 broken females, 1 broken male missing right gonopod (CUMZ), Donsak District, Nang Gam Beach, limestone mountain, 9°18'53"N, 99°45'40"E, ca. 20 m a.s.l., 10 October 2008, leg. S. Panha, P. Tongkerd, and ASRU members. 7 males, 1 male missing left gonopod, 6 females, 1 male missing gonopods, 1 broken male missing left gonopod (CUMZ), Ko Samui District, Mo Ko Ang Thong National Marine Park, Ko Mae Koh, 9°39'06"N, 99°40'02"E, ca. 23 m a.s.l., 6 June 2009, leg. S. Panha and ASRU members. 1 broken male missing left gonopod, 4 males, 3 females, 1 male missing right gonopod, 1 male missing gonopods (CUMZ), Ko Samui District, Mo Ko Ang Thong National Marine Park, Ko Wua Talap, 9°38'08"N, 99°40'16"E, ca. 20 m a.s.l., 6 June 2009, leg. S. Panha and ASRU members. 1 male, 3 females (CUMZ), Donsak District, Nang Gam Beach, 9°18'53"N, 99°45'41"E, ca. 26 m a.s.l., 2 December 2015, leg. S. Panha, P. Tongkerd, and ASRU members.

Nakhon Si Thammarat Province: 1 male (CUMZ), Khanom District, Khao Krot Bureau of Monks, near Khao Krot Cave, 9°14'29"N, 99°48'07"E, ca. 19 m a.s.l., 23 October 2016, leg. W. Siriwut and ASRU members.

Body bright orange, low degree of elevation of paraterga, femora 5 and 6 strongly humped ventrally in middle part, collum with row of 3+3 anterior setae and metaterga with rows of 2+2 anterior and 2+2 posterior small tubercles. Similar in these respects to D. delfae and D. perakensis sp. n., but differs from those by having paraterga of collum quite long; lateral sulcus (ls) quite shallow; lamina lateralis (ll) stout and compact, ventral ridge (vrl) short; process (plm) of lamina medialis crenate; sternal lobe between male coxae 4 thin when seen in lateral view.

The name is Latin adjective and refers to the lamina lateralis (ll) of the gonopod which bears some resemblance to the “hooded” head of the oranda breed of goldfish (Carassius auratus).

SIZE: Length 21–24 mm (male), 25–27 mm (female); width of midbody metazona ca. 1.7 mm (male), 2.1 mm (female). Width of head < collum < body ring 2 < 3 = 4 < 5–16, thereafter body gradually tapering towards telson.

COLOUR (Fig. 9A–D): In life with body bright orange; antenna dark brown, except distal part of antennomere 7 and antennomere 8 whitish; head brown; paraterga, metaterga and surface below paraterga orange; legs, sterna and epiproct orange-ish yellow; a few basal podomeres whitish orange; prozona and metazona (metaterga) with wide black stripe, conspicuous on rings 4–19.

ANTENNAE (Fig. 10D): Moderately long and slender, reaching to body ring 6 (male) and 5 (female) when stretched dorsally.

COLLUM (Fig. 10A): With 1 transverse anterior row of 3+3 setae; paraterga of collum low, almost horizontal, directed caudolaterad, with two inconspicuous setiferous notches on lateral margin.

TEGUMENT: Strongly shining and smooth; prozona finely shagreened; collum, metaterga, sterna and epiproct smooth; surface below paraterga finely microgranulate.

METATERGA (Fig. 10A–C): With 2 transverse rows of setae and inconspicuous tubercles; metaterga 2–18 with 2+2 anterior and 2+2 posterior tubercles; metatergum 19 with 2+2 anterior and 2+2 posterior setae.

PARATERGA (Fig. 10E, F): Directed caudolaterad on body rings 2–17, elevated at ca. 30°–35° (male) 30° (female), directed increasingly caudad on body rings 18 and 19; anterior margin with 2 distinct notches, without tiny denticle near tip.

TELSON (Fig. 11C–G): Epiproct: tip emarginate; lateral setiferous tubercles small and inconspicuous; apical tubercles inconspicuous. Hypoproct subsemicircular; caudal margin round, with very small and inconspicuous setiferous tubercles.

STERNA (Fig. 12): Cross-impressions shallow. Sternal lobe between male coxae 4 subrectangular (in some specimens subtrapeziform), tip subtruncate (in some specimens subemarginate or round).

LEGS (Fig. 11H–J): Long and slender. Male femora 5 and 6 strongly humped ventrally in middle portion.

GONOPODS (Figs 13, 14): Coxa (cx) longer than prefemur. Cannula (ca) slightly stout. Telopodite quite stout. Prefemur (pfe) ca. 2/3 as long as femur. Femur (fe) somewhat stout. Mesal sulcus (ms) conspicuous and very deep; lateral sulcus (ls) shallow. Postfemur (pof) conspicuous, ventrally narrow and short. Solenophore (sph) well-developed: lamina lateralis (ll) swollen, stout and compact, anterolaterally with a distinct furrow; ventral ridge (vrl) short: lamina medialis (lm) well-developed; process (plm) short, wide and thin, tip crenate; distal lobe (dlm) distally with one lamella, tip directed anteriad; broad lobe (blm) indistinctly separated from distal lobe (dlm) by a shallow indentation. Solenomere (sl) long.

Known only from Surat Thani and Nakhon Si Thammarat Provinces. All specimens were collected in limestone mountains (on the mainland and on two islands) (Fig. 9E). We also surveyed other islands in Mo Ko Ang Thong National Marine Park, but found no specimens of D. aurata sp. n. The new species is probably distributed along the islands in the Gulf of Thailand and also on the mainland near the type locality. We regard it as endemic for Thailand.

Desmoxytes aurata sp. n. is morphologically similar to D. delfae and D. perakensis sp. n. in the remarkable orange colouration, as well as some morphological characters (except characters in diagnosis). These three species show allopatric distribution ranges, and the big mountain ranges known as the Nakhon Si Thammarat and Sunkala Khiri mountains possibly act as dispersal barriers.

The bright orange colouration is without doubt aposematic. There is some distinct variation within populations in the sternal lobe between male coxae 4, especially its shape: in most specimens the lobe is subrectangular, in others subtrapeziform, and its tip also varies – subtruncate/ subemarginate/ round. The shape of the sternal lobe of the new species is similar to that seen in D. delfae and D. perakensis sp. n., however, it looks thinner than those when seen in lateral view.

Desmoxytes cervina was found together with the new species in some localities.

Male (CUMZ), THAILAND, Phrae Province, Long District, in front of Sareethai Cave, 18°16'43"N, 100°03'29"E, ca. 292 m a.s.l., 21 October 2014, leg. C. Sutcharit, W. Siriwut, K. Inkhavilay and R. Srisonchai.

27 males, 7 females (CUMZ), 3 males, 2 females (ZMUC), same data as holotype. 5 males, 3 females (CUMZ), THAILAND, Phrae Province, Long District, in front of Sareethai Cave, 18°16'43"N, 100°03'29"E, ca. 292 m a.s.l., 21 July 2008, leg. N. Likhitrakarn. 1 male, 3 females (CUMZ), THAILAND, Lampang Province, Mae Tha District, Nakraua Subdistrict, Wat Tham Phra Sabai, 18°05'32"N, 99°32'03"E, ca. 328 m a.s.l., 21 July 2008, leg. S. Panha, P. Tongkerd and N. Likhitrakarn. 1 male, 5 females (CUMZ), THAILAND, Lampang Province, Mae Tha District, Tham Chakkrabhat Monastery (Wat Tham Chakkrabhat), 18°06'02"N, 99°56'48"E, ca. 210 m a.s.l., 8 October 2007, leg. U. Bantaowong, R. Chanabun, P. Pimvichai and T. Krutchuen.

all from THAILAND: 2 males, 5 broken males, 1 male with rings 1–8, 6 broken females (CUMZ), Uttaradit Province, Thong Saen Khan District, Tham Chan (Chan Cave), 17°35'00"N, 100°25'21"E, ca. 164 m a.s.l., 22 July 2008, leg. S. Panha and ASRU members. 1 male, 1 female (CUMZ), Lampang Province, Mae Tha District, Nakraua Subdistrict, Wat Tham Phra Sabai, 18°05'32"N, 99°32'03"E, ca. 328 m a.s.l., 21 July 2008, leg. S. Panha and ASRU members.

Differs from all other Desmoxytes species by the combination of the following characters; body purple pink; collum with rows of 3+3 anterior, 1+1 intermediate and 2+2 posterior setiferous tubercles; sternal lobe between male coxae 4 subrectangular, quite long and thick when seen in lateral view; ventral lobe (vll) of lamina lateralis quite long, digitiform, directed ventrad; distal lobe (dlm) distally with two lamellae (mesal lamella smaller than lateral one; lateral lamella thin, tip directed almost in vertical plane); broad lobe (blm) thick, obviously demarcated from distal lobe by a deep and wide indentation; solenomere (sl) short.

THAILAND, Phrae Province, Long District, in front of Sareethai Cave.

(updated from Srisonchai et al. 2016). SIZE: Length 28–33 mm (male), 33–38 mm (female); width of midbody metazona ca. 2.2 mm (male), 3.5 mm (female). Width of head < collum = body ring 2 = 3 ≤ 4 < 5 < 6–17, thereafter body gradually tapering toward telson.

COLOUR: In life with body shocking pink to purple (some female specimens brownish pink); paraterga vivid pink; metaterga and surface below paraterga brownish pink to brownish purple; head brown; antenna blackish brown (except distal part of antennomere 7 and antennomere 8 whitish); legs, sterna and epiproct pink; a few basal podomeres whitish pink. Colour in alcohol: after two years changed to pale brown.

ANTENNAE: Long and slender, reaching to body ring 6 (male), and 5 (female) when stretched dorsally.

COLLUM: With 3 transverse rows of setiferous tubercles, 3+3 anterior, 1+1 intermediate and 2+2 posterior tubercles (excluding small setiferous notches at base of paraterga), lateral tubercles of posterior row located at almost halfway to intermediate row; paraterga of collum low, elevated at ca. 30°, directed caudolaterad, with two setiferous notches on lateral margin (first inconspicuous notch located at the base of paratergum, second one conspicuous).

TEGUMENT: Moderately shining; collum, metaterga and surface below paraterga coarsely microgranulate; prozona finely shagreened; paraterga, sterna and epiproct smooth.

METATERGA: With 2 transverse rows of setiferous tubercles and rose thorn-like spines; metaterga 2–18 with 2+2 anterior and 2+2 posterior spines; metatergum 19 with 2+2 anterior and 2+2 posterior spines (tubercles in some specimens).

PARATERGA: Directed caudolaterad on body rings 2–17, elevated at ca. 45° (male) 40° (female); directed increasingly caudad on body rings 18 and 19; anterior margin with 2 distinct notches, on lateral margin of body rings 9, 10, 12, 13, 15–18 with tiny denticle near the tip.

TELSON: Epiproct: tip subtruncate; lateral setiferous tubercles inconspicuous; apical tubercles inconspicuous. Hypoproct subsemicircular (in some specimens subtrapeziform); caudal margin round, with inconspicuous setiferous tubercles.

STERNA: Cross-impressions shallow. Sternal lobe between male coxae 4 swollen, usually subrectangular (in some specimens subtrapeziform), quite long and slightly thick when seen in lateral view, tip usually emarginate (some specimens subtruncate).

LEGS: Very long and slender. Male femora 5 and 6 strongly humped ventrally in middle part.

GONOPODS (Fig. 15): Coxa (cx) longer than prefemur. Cannula (ca) long and slender. Prefemur (pfe) ca. 2/3 as long as femur. Femur (fe) long and slender. Mesal sulcus (ms) and lateral sulcus (ls) very deep and wide. Postfemur (pof) conspicuous, ventrally very wide. Solenophore (sph) well-developed: lamina lateralis (ll) swollen, surface rough; ventral lobe (vll) quite long, digitiform, directed ventrad: lamina medialis (lm) well-developed; process (plm) long, spine-like, tip emarginate – not terminating in spines (in some specimens almost blunt), directed mesoanteriad; distal lobe (dlm) distally with two distinct lamellae (mesal lamella slightly smaller than lateral one; lateral lamella thin and broad, tip directed almost in vertical plane); broad lobe (blm) thick, obviously demarcated from distal lobe (dlm) by a deep and wide indentation. Solenomere (sl) quite short.

Known only from the type locality and nearby areas. Desmoxytes breviverpa was collected from limestone forest, crawling on logs and litter (Srisonchai et al. 2016). We believe it may be distributed though the central and southern parts of north Thailand. This species has been reported from Phrae, Lampang and Uttaradit Provinces. Therefore, D. breviverpa should be regarded as endemic for Thailand.

Specimens collected from Uttaradit Province south of the type locality showed the same morphological characters as the type specimens. No variation was found between populations although most limestone areas in north Thailand are geographically isolated by several big mountain ranges and quite far from each other.

Srisonchai et al. (2016) discussed variation of the tip of sternal lobe between male coxae 4; we found additional variation within populations as follows:

– Tip of sternal lobe in some specimens almost truncate (=subtruncate), albeit other specimens show an emarginate tip (slightly or deeply emarginate).

– Tip of hypoproct in some individuals subsemicircular, in others subtrapeziform.

– Tip of process (plm) of lamina medialis emarginate in most specimens, but almost blunt in some.

None known.

Srisonchai et al. (2016, pp. 99–103) wrote in the description of this species that the paraterga (including paraterga of collum) are directed dorsolaterad. In fact they are directed caudolaterad as described above.

Lectotype. Male (NHMUK, Bm 1892.5.4.76), MYANMAR, south Tenasserim, leg. E. W. Oates, most legs missing. Lectotype here designated.

Holotype (D. pterygota): Male (ZMUC), THAILAND, Ranong Province, Kapoe District, in forest at big waterfalls south of Kapoe (Khao Phra Narai Waterfall?), 15 November 1990, leg. M. Andersen and A. R. Rasmussen.

Paratypes (D. pterygota): 2 males (ZMUC), 1 male (ZMUM), THAILAND, Ranong Province, Kapoe District, in forest at big waterfalls south of Kapoe, 15 November 1990, leg. M. Andersen and A. R. Rasmussen.

MYANMAR: 10 males, 7 females (CUMZ), Tanintharyi Region, Lenya National Park, Phayarhtan Cave (Buddha Cave), approximately 10 km from Ban Nam Yen Village, inside the deep rainforest near limestone mountain, on decaying wood and under bark, 11°13'50"N, 99°10'35"E, ca. 85 m a.s.l., 6 June 2015, leg. C. Sutcharit, R. Chanabun and R. Srisonchai.

THAILAND: Chumphon Province: 1 male, 2 females (CUMZ), Mueang Chumphon District, Tham Chang Phuek Bureau of Monks, 10°26'47"N, 99°02'06"E, ca. 93 m a.s.l., 13 March 2017, leg. C. Sutcharit, R. Srisonchai and ASRU members. 1 male (CUMZ), Sawi District, Wat Nam Cha, 10°17'54"N, 99°01'57"E, ca. 105 m a.s.l., 3 July 2017, leg. C. Sutcharit, R. Srisonchai and ASRU members.

Krabi Province: 1 male (CUMZ), Ao-Luek District, P.N. Moutain Resort, 8°24'09"N, 98°44'18"E, ca. 60 m a.s.l., 30 August 2015, leg. C. Sutcharit and ASRU members. 1 male remaining rings 7–20 (CUMZ), Khlong Thom District, Emerald Blue Pool, 7°55'30"N, 99°16'05"E, ca. 67 m a.s.l., 15 January 2009, leg. S. Panha and ASRU members. 1 female (CUMZ), Muang Krabi District, Wat Tham Sue (Tiger Cave), valley behind Tiger Cave, 8°07'38"N, 98°55'27"E, ca. 86 m a.s.l., 18 May 2010, leg. S. Panha and ASRU members. 2 males, 3 females, 1 broken male and missing gonopods (CUMZ), Muang Krabi District, Wat Tham Sue (Tiger Cave), valley behind Tiger Cave, 8°07'38"N, 98°55'27"E, ca. 86 m a.s.l., 7 October 2006, leg. S. Panha and ASRU members. 1 male, 4 females (CUMZ), Muang Krabi District, Wat Tham Sue (Tiger Cave), valley behind Tiger Cave, 8°07'38"N, 98°55'27"E, ca. 86 m a.s.l., 24 August 2014, leg. S. Panha and ASRU members. 2 males, 1 female, 1 juvenile (CUMZ), Muang Krabi District, Wat Tham Sue (Tiger Cave), valley behind Tiger Cave, 8°07'38"N, 98°55'27"E, ca. 86 m a.s.l., 30 August 2015, leg. C. Sutcharit, R. Srisonchai and ASRU members. 15 males, 3 females, 1 juvenile (CUMZ), Muang Krabi District, Wat Tham Sue (Tiger Cave), valley behind Tiger Cave, 8°07'38"N, 98°55'27"E, ca. 86 m a.s.l., 9 July 2017, leg. C. Sutcharit, R. Srisonchai and ASRU members. 11 males, 6 females, 1 juvenile (CUMZ), Muang Krabi District, Wat Tham Sue (Tiger Cave), valley behind Tiger Cave, 8°07'38"N, 98°55'27"E, ca. 86 m a.s.l., 25 July 2017, leg. C. Sutcharit, R. Srisonchai and ASRU members.

Nakhon Si Thammarat Province: 2 males, 2 females, 4 juveniles (ZMUC), Sichon District, Khao Lark Waterfall, 25 August 2007, leg. ASRU members. 1 female (CUMZ), Thung Song District, Yong Waterfall, 8°10'21"N, 99°44'34"E, ca. 138 m a.s.l., 20 July 2008, leg. S. Panha and ASRU members. 1 male missing gonopods (CUMZ), Nopphitam District, Krung Ching Waterfall, 8°43'27"N, 99°40'04"E, ca. 173 m a.s.l., 17 January 2013, leg. C. Sutcharit, R. Srisonchai and ASRU members. 1 female (CUMZ), Khanom District, Nai Plao Beach, 9°07'26"N, 99°52'60"E, ca. 20 m a.s.l., 4 December 2015, leg. S. Panha and ASRU members. Many specimens (CUMZ), Tham Phannara District, Wat Tham Kanlaya Namit, 8°30'48"N, 99°22'52"E, ca. 51 m a.s.l., 4 July 2017, leg. C. Sutcharit, R. Srisonchai and ASRU members. Many specimens (CUMZ), Tham Phannara District, Wat Tham Thong Phannara, 8°25'21"N, 99°22'47"E, ca. 32 m a.s.l., 4 July 2017, leg. C. Sutcharit, R. Srisonchai and ASRU members.

Phang Nga Province: 1 male missing gonopods, 3 males, 1 female (CUMZ), Thai Mueang District, Khaolak-Lumru National Park, 8°37'35"N, 98°14'25"E, ca. 72 m a.s.l., 7 October 2006, leg. S. Panha and ASRU members. 1 male, 1 female (ZMUC), Thap Put District, Highway No. 4 Phet Kasem Road ca. 0.5 km north of the Headquarters of the Khao Lak–Lamru National Park, on the street next to secondary rainforest. 8°37'N, 98°14'E, ca. 30–40 m a.s.l., 29 August–12 September 2008, leg. N. Laufer. 1 male missing gonopods, 1 male (CUMZ), Khura Buri District, Mu Koh Surin National Park, Koh Surin Nuea, 9°26'27"N, 97°52'11"E, ca. 39 m a.s.l., 8 April 2012, leg. S. Panha and ASRU members. 1 broken male and missing gonopods (CUMZ), Mueang Phang Nga District, Tham Nam Pud, 8°27'50"N, 98°32'36"E, ca. 58 m a.s.l., 7 October 2006, leg. S. Panha and ASRU members. Many specimens (CUMZ), Mueang Phang Nga District, Tham Nam Pud, 8°27'50"N, 98°32'36"E, ca. 58 m a.s.l., 5 August 2015, leg. C. Sutcharit, R. Srisonchai and ASRU members. 1 male (CUMZ), Mueang Phang Nga District, Tham Pha Sue Bureau of Monks, 8°28'24"N, 98°32'15"E, ca. 78 m a.s.l., 10 July 2017, leg. C. Sutcharit, R. Srisonchai and ASRU members. 2 females (CUMZ), Mueang Phang Nga District, Tham Nam Pud Bureau of Monks, 8 October 2006, leg. S. Panha and ASRU members. 1 male, 1 female (CUMZ), Mueang Phang Nga District, Tao Thong Waterfall, 8°29'08"N, 98°35'09"E, ca. 25 m a.s.l., 7 October 2006, leg. S. Panha and ASRU members. 1 female (CUMZ), Mueang Phang Nga District, Phung Chang Cave, 8°26'34"N, 98°30'59"E, ca. 24 m a.s.l., 26 September 2009, leg. S. Panha and ASRU members. 3 males, 2 females, 14 juveniles (CUMZ), Mueang Phang Nga District, Phung Chang Cave, 8°26'34"N, 98°30'59"E, ca. 24 m a.s.l., 6 August 2014, leg. C. Sutcharit, R. Srisonchai and ASRU members. Many specimens (CUMZ), Mueang Phang Nga District, Phung Chang Cave, 8°26'34"N, 98°30'59"E, ca. 24 m a.s.l., 5 August 2015, leg. C. Sutcharit, R. Srisonchai and ASRU members. 5 males, 4 females (CUMZ), Mueang Phang Nga District, Phung Chang Cave, 8°26'34"N, 98°30'59"E, ca. 24 m a.s.l., 8 August 2016, leg. C. Sutcharit, R. Srisonchai, and ASRU members. 3 males, 2 juveniles (CUMZ), Takua Thung District, Wat Suwan Khuha (Monkey Cave), 8°25'42"N, 98°28'22"E, ca. 25 m a.s.l., 8 August 2016, leg. C. Sutcharit, R. Srisonchai, and ASRU members. Many specimens (CUMZ), Thap Put District, Wat Khiri Wong (Tham Kob), 8°31'57"N, 98°34'40"E, ca. 97 m a.s.l., 9 July 2017, leg. C. Sutcharit, R. Srisonchai, and ASRU members.

Phuket Province: 1 male of Desmoxytes sp. (ZMUC), Thalang District, Thepkrasattree Subdistrict, Tonsai Waterfall, 8°01'44"N, 98°21'45"E, ca. 67 m a.s.l., 12 October 1991, leg. M. Anderson, O. Martin, and N. Scharff. 1 female (CUMZ), Mueang Phuket District, Panwa Cave, 7°48'04"N, 98°24'34"E, ca. 25 m a.s.l., June 2007, leg. S. Panha and ASRU members. 1 female (CUMZ), Mueang Phuket District, Panwa Cave, 7°48'04"N, 98°24'34"E, ca. 25 m a.s.l., 5 November 2007, leg. S. Panha and ASRU members.

Ranong Province: 1 male (CUMZ), Kra Buri District, Tham Phra Khayang, 10°19'35"N, 98°45'54"E, ca. 51 m a.s.l., 21 November 2015, leg. S. Panha, P. Tongkerd, and A. Pholyotha. 1 female (CUMZ), Kra Buri District, Bok Krai Waterfall, 10°22'35"N, 98°51'22"E, ca. 106 m a.s.l., 3 January 2013, leg. S. Panha, P. Tongkerd, and A. Pholyotha.

Surat Thani Province: 2 broken and mixed females, 2 females remaining rings 13–20, 1 broken female (CUMZ), Phanom District, Khlong Phanom National Park, 8°52'44"N, 98°40'26"E, ca. 68 m a.s.l., 28 August 2007, leg. S. Panha and ASRU members. 1 male, 6 juveniles (CUMZ), Phanom District, Khlong Phanom National Park, Pha Daeng, 8°53'41"N, 98°33'12"E, ca. 67 m a.s.l., 7 August 2016, leg. C. Sutcharit, R. Srisonchai, and ASRU members. 8 males, 3 females (CUMZ), Phanom District, Khlong Phanom National Park, Pha Daeng, 8°53'41"N, 98°33'12"E, ca. 67 m a.s.l., 1 August 2017, leg. C. Sutcharit, R. Srisonchai, and ASRU members. 4 males (CUMZ), Phanom District, Ban Song Phi Nong, 8°50'51"N, 98°44'16"E, ca. 74 m a.s.l., 7 August 2016, leg. C. Sutcharit, R. Srisonchai, and ASRU members. 10 males, 3 females, 1 broken male missing gonopods (CUMZ), Ban Ta Khun District, Ratchaprapa Dam, 8°57'22"N, 98°48'22"E, ca. 53 m a.s.l., 8 October 2008, leg. S. Panha and ASRU members. Many specimens (CUMZ), Ban Ta Khun District, Ratchaprapa Dam, 8°57'22"N, 98°48'22"E, ca. 53 m a.s.l., 4 August 2014, leg. C. Sutcharit, R. Srisonchai, and ASRU members. Many specimens (CUMZ), Ban Ta Khun District, Ratchaprapa Dam, 8°57'22"N, 98°48'22"E, ca. 53 m a.s.l., 3 August 2015, leg. C. Sutcharit, R. Srisonchai, and ASRU members. 1 male (CUMZ), Ban Ta Khun District, Ratchaprapa Dam, 8°57'22"N, 98°48'22"E, ca. 53 m a.s.l., 5 August 2016, leg. C. Sutcharit, R. Srisonchai, and ASRU members. 1 male (CUMZ), Ban Ta Khun District, Khlong Hoi, 8 October 2008, leg. S. Panha and ASRU members. 2 males, 1 male missing gonopods, 1 juvenile, 1 broken juvenile (CUMZ), Ban Ta Khun District, Khao Wong Water Supply Station, 8°55'47"N, 98°56'25"E, ca. 97 m a.s.l., 9 October 2008, leg. S. Panha and ASRU members. 2 males (CUMZ), Ban Ta Khun District, Wat Khao Pang (Suspension Bridge), 8°56'54"N, 98°49'21"E, ca. 24 m a.s.l., 5 May 2017, leg. S. Panha and ASRU members. 1 male, 1 male missing gonopods, 2 females, 2 broken females, 1 juvenile (CUMZ), Khirirat Nikhom District, Wat Satit Khirirom, 9°01'48"N, 98°59'12"E, ca. 47 m a.s.l., 8 October 2008, leg. S. Panha and ASRU members. 1 male (CUMZ), Khirirat Nikhom District, Wat Satit Khirirom, 9°01'48"N, 98°59'12"E, ca. 47 m a.s.l., 5 September 2009, leg. S. Panha and ASRU members. 27 males, 10 females (CUMZ), 2 males, 1 female (ZMUC), 1 male, 1 female (ZMUM), 1 male, 1 female (NHMW), 1 male, 1 female (NHMUK), Khirirat Nikhom District, Wat Satit Khirirom, 9°01'48"N, 98°59'12"E, ca. 47 m a.s.l., 10 July 2017, leg. C. Sutcharit, R. Srisonchai, and ASRU members. 1 male missing right gonopod (CUMZ), Khirirat Nikhom District, km3 near Khirirat Nikhom City, 9 October 2008, leg. S. Panha and ASRU members. 1 male, 1 female (CUMZ), Khirirat Nikhom District, Tham Wang Badan Bureau of Monks, 8°56'09"N, 98°57'28"E, ca. 69 m a.s.l., 3 August 2017, leg. C. Sutcharit, R. Srisonchai, and ASRU members. 3 broken males (CUMZ), Ko Samui District, Na Muang Waterfall, 9°27'58"N, 99°59'02"E, ca. 53 m a.s.l., 27 January 2006, leg. S. Panha and ASRU members. 1 female (CUMZ), Ko Samui District, Na Muang Waterfall, 9°27'58"N, 99°59'02"E, ca. 53 m a.s.l., 4 December 2015, leg. S. Panha, P. Tongkerd and A. Pholyotha. 1 male remaining rings 1–11, 1 female (ZMUM), Ko Samui, Thailand, June 2013, leg. Korabushkin Daniil. 10 males, 5 females, 4 juveniles (CUMZ), Wiang Sa District, Khiri Rat Pattana Bureau of Monks (Wat Khao Poon), 8°31'37"N, 99°22'59"E, ca. 68 m a.s.l., 4 July 2017, leg. C. Sutcharit, R. Srisonchai, and ASRU members. 1 male, 1 female (CUMZ), Ban Na San District, Khao Kok Maharat Bureau of Monks, 8°41'33"N, 99°22'45"E, ca. 71 m a.s.l., 4 July 2017, leg. C. Sutcharit, R. Srisonchai, and ASRU members.

Differs from other Desmoxytes species by the combination of the following characters: body colour brownish red/brown/pale brown; paraterga brownish red/red/yellowish brown; metaterga 2–4 with 2+2 (anterior row) and 2+2 (posterior row) tubercles, metaterga 5–19 with 2(1)+2(1) (anterior row) and 2+2 (posterior row) tubercles; lamina lateralis (ll) stout; anterolaterally with a long, distinct, deep and wide furrow; ventral ridge (vrl) of lamina lateralis very long, wide, conspicuous; process (plm) of lamina medialis long, distinctly demarcated from distal lobe, irregularly shaped, directed mesodorsad; distal lobe (dlm) of lamina medialis distally with one distinct lamella; broad lobe (blm) slightly thick at the edge, distinctly demarcated from distal lobe (dlm) by a wide and shallow indentation.

MYANMAR, southern Myanmar, Tenasserim [Tanintharyi Region].

SIZE: Length 25–31 mm (male), 33–39 mm (female); width of midbody metazona ca. 2.1 mm (male), 3.6 mm (female). Width of head < collum < body ring 2 ≥ 3 = 4 < 5–16, thereafter body gradually tapering towards telson.

COLOUR (Figs 16, 17A–E): In life with two colour morphs. Brownish red morph – body brownish red (testaceous); head and antenna brownish black (except distal part of antennomere 7 and antennomere 8 whitish); collum, epiproct and legs brown; rings 2–3 brownish red or brown; metaterga, surface below paraterga and sterna brownish red; paraterga brownish red or red; a few basal podomeres reddish brown. Brown morph – body brown (female pale brown); head and antenna (except distal part of antennomere 7 and antennomere 8 whitish) brownish black or black; collum and rings 2–3 brownish black; metaterga, surface below paraterga, epiproct and legs brown; paraterga yellowish brown; sterna pale brown; a few basal podomeres brownish white. Colour in alcohol: after 100 years changed to greenish dark or greenish brown, after 5–10 years changed to pale brown.

ANTENNAE (Fig. 18D): Very long and slender, reaching to body ring 6 or 7 (male) and 5 or 6 (female) when stretched dorsally.

COLLUM (Fig. 18A): With 1 transverse row of setae, 3+3 anterior setae; paraterga of collum low, elevated at ca. 15°–20°, directed caudolaterad, with two inconspicuous notches on lateral margin.

TEGUMENT: Moderately shining; collum coarsely microgranulate; prozona finely shagreened; metaterga and surface below paraterga finely microgranulate; paraterga, sterna and epiproct smooth.

METATERGA (Fig. 18A–C): With 2 transverse rows of tubercles; metaterga 2–4 with 2+2 anterior tubercles and 2+2 posterior tubercles; metaterga 5–19 with 2(1)+2(1) anterior tubercles and 2+2 posterior tubercles (lateral setae of anterior row in some specimens very distinct, in some specimens poorly developed).

PARATERGA (Fig. 18E, F): Long, strongly developed; directed caudolaterad on body rings 2–17, elevated at ca. 45° (male) 40° (female); directed increasingly caudad on body rings 18 and 19; anterior margin with 2 distinct notches, on lateral margin of body rings 9, 10, 12, 13, 15–18 with tiny denticle near the tip.

TELSON (Fig. 19C–G): Epiproct: tip usually truncate (in some specimens slightly emarginate); lateral setiferous tubercles and apical setiferous tubercles conspicuous, coniform. Hypoproct subtrapeziform; caudal margin slightly round (in some specimens subtruncate), with inconspicuous setiferous tubercles.

STERNA (Fig. 20): Cross-impressions shallow (in some specimens slightly deep). Sternal lobe between male coxae 4 swollen, usually subtrapeziform (in some specimens subsemicircular), usually thick when seen in lateral view (in some specimens thin), slightly attenuated near tip, tip round/subtruncate/slightly emarginate.

LEGS (Fig. 19H–J): Very long and slender. Male femora 5 and 6 strongly humped ventrally in middle portion.

GONOPODS (Figs 21, 22): Coxa (cx) longer than prefemur. Cannula (ca) long and slender. Prefemur (pfe) ca. 2/3 as long as femur. Femur (fe) long and slender. Mesal sulcus (ms) and lateral sulcus (ls) conspicuous, very deep and narrow. Postfemur (pof) conspicuous, ventrally narrow. Solenophore (sph) well-developed: lamina lateralis (ll) stout; anterolaterally with a long, distinct, deep and wide furrow; with a long, wide and conspicuous ventral ridge (vrl): lamina medialis (lm) well-developed; process (plm) long, of irregular shape (varies within population), distinctly demarcated from distal lobe, tip blunt (in some specimens terminating in spines), directed mesodorsad; distal lobe (dlm) distally with one distinct lamella; broad lobe (blm) slightly thick at the edge, distinctly demarcated from distal lobe (dlm) by a wide and shallow indentation. Solenomere (sl) long.

Desmoxytes cervina is known from Myanmar (Lenya National Park) and Thailand (Chumphon, Krabi, Nakhon Si Thammarat, Phang Nga, Phuket, Ranong, and Surat Thani Provinces). The type locality is in south of Tenasserim, but we do not know the exact location, probably somewhere near Taninthayi township. The locality of the paralectotype (see below) “Malewoon, Tenasserim”, is currently known as Maliwan Village.

Almost all specimens were collected from limestone habitats, a few specimens were collected from granitic areas. Interestingly, D. cervina was also found in some islands in both the Andaman Sea and the Gulf of Thailand (Mu Koh Surin National Park, Phuket, and Ko Samui).

Decker (2010) classified “D. pterygota” as endemic for Thailand due to its narrow range near the type locality. After intensive collecting and synonymising of D. cervina and “D. pterygota”, the known distribution range has expanded to southern Myanmar and southern Thailand.

This species was found living together with D. delfae and D. corythosaurus sp. n. According to our observations, it is probable that they may even share microhabitat: humid rocks, branches of trees and rock walls.

This species was described based on two males, one of which was collected by L. Fea (Malewoon, Tenasserim – MSNG) and the other collected by E. W. Oates (south Tenasserim – NHMUK).

Jeekel (1964) revised this species by examining the male in MSNG; he stated that “in anticipation of the designation as holotype of the specimen collected by Oates in the British Museum, I have labelled this specimen as paratype”. However, the holotype has never been designated in the original description. R.L. Hoffman visited NHMUK and labelled the specimen collected by Oates as paratype, but he did not publish this designation, which is in conflict with Jeekel’s (1964) paratype designation. Therefore, we here designate the male collected by Oates and belonging to NHMUK as lectotype to stabilise the name. The male in MSNG (which we have not examined) is considered to be a paralectotype.

Some specimens kept in MHNG and identified as “D. pterygota” by Decker (2010), are probably D. cervina because the localities fall within the distribution range of this species.

This is the first report of the colour of living specimens for this species; the brownish red colour is apparently aposematic. Pocock (1895) and Golovatch and Enghoff (1994) did not mention the colour of living specimens. We found two colour morphs of D. cervina: brownish red and brown. The majority of specimens are brownish red, and the minority are brown; the latter colour can be found in a few specimens within a population.

Interestingly, brownish red and brown morphs occur in the same habitat in the valley behind Tiger Cave and Ban Song Phi Nong. The brown morph was found at Wat Tham Kanlaya Namit, Wat Tham Thong Phannara, Tham Nam Pud, Phung Chang Cave and Wat Suwan Khuha (Monkey Cave). Specimens from the remaining localities are of the brownish red morph. We examined the morphological characters of all specimens of both colour morphs; all specimens exhibit the same morphology, especially in the gonopods which are identical. Perhaps the difference in colour is caused by environmental factors and/or genetic variation.

We assume that the type material of both D. cervina, collected by Oates and Fea a hundred years ago, and “D. pterygota” collected by M. Andersen and A.R. Rasmussen 17 years ago, did probably exhibit brownish red colour because all specimens near the type localities are brownish red. We found additionally that the colour of some females is pale brownish red or pale brown, and the colour of juveniles is pale brown.

Jeekel (1964) wrote in his redescription that D. cervina shows collum without setae, metaterga 2–19 with 1+1 anterior tubercles and 2+2 posterior tubercles. Golovatch and Enghoff (1994) distinguished “D. pterygota” from D. cervina by having smooth metaterga. They also described “D. pterygota” as having no pleurosternal carinae, antenna reaching to ring 4 in male, collum with 2 rows of 3+3 anterior setae and 1+1 intermediate setae, metaterga 2–19 with 2+2 anterior cones and 2+2 posterior cones. After examination of all type material and newly collected specimens of D. cervina and “D. pterygota”, we found that:

– all specimens of D. cervina and “D. pterygota” display fine microgranulation on the metaterga.

– all specimens have pleurosternal carinae, in body ring 2 very distinct and crest-like, in ring 3 very small, thereafter absent.

– antenna reaches to ring 6–7 in male and to ring 5–6 in female of both D. cervina and “D. pterygota”.

– collum has 3+3 anterior setae in all specimens – because Jeekel studied old preserved specimens, the setae may have been lost over time.

– metaterga 5–19 varies within populations; metaterga 2–4 with 2+2 anterior tubercles and 2+2 posterior tubercles, metaterga 5–19 with 2+2/1+1 anterior and 2+2 posterior tubercles.

Several other characters show variability, as follows:

I. variation within populations

– size of tubercles on metaterga: tubercles conspicuous in some specimens, inconspicuous in the others (bigger and more obvious in the holotype of “D. pterygota” than in the lectotype of D. cervina).

– tip of process (plm) of lamina medialis: in some specimens terminating in one blunt process, in others terminating in a sharp spine.

– shape of sternal lobe between male coxae 4: in some individuals subtrapeziform, in others subsemicircular.

– tip of sternal lobe between male coxae 4: in some specimens round, in some subtruncate, in others emarginate.

– cross-impressions on sternum: in some individuals shallow and faint, in others slightly deep.

– tip of epiproct: in some individuals truncate, in others slightly emarginate.

– caudal margin of hypoproct: in some specimens slightly round, in others subtruncate.

– size of sternal lobe between male coxae 4 when seen in lateral view in specimens from Wat Satit Khirirom: in some specimens thick, in others thin.

II. variation between populations

– colour: all individuals in the same population usually have the same colour: brown or brownish red. However, in some populations (valley behind Tiger Cave and Ban Song Phi Nong) brownish red and brown individuals coexist.

Although the male paralectotype of D. cervina (in MSNG) has not been examined by us, the morphological characters for this specimen as redescribed by Jeekel (1964) perfectly match the morphology of the numerous other specimens we have seen. Based on our analysis of morphology and variation of these specimens we have synonymised “D. pterygota” under D. cervina.

Distribution data support the synonymisation: the type localities of “D. pterygota” (Ranong Province) and D. cervina (Tenasserim = Taninthayi) are very close to each other. Our intensive surveys prove that this species is distributed quite widely, but nevertheless is found in south Myanmar and south Thailand only.

During the field survey, we noticed several adult males of D. cervina which were infested with red mites. The mites are probably larvae of the genus Leptus Latreille, 1796 (Prostigmata, family Erythraeidae). Associations between mites and millipedes may be of a phoretic or a parasitic nature (Gerdeman et al. 2000, Swafford and Bond 2010, Farfan and Klompen 2012, Mwabvu 2014). In Fig. 17C and D, several engorged mites are seen along with a few small, non-engorged ones, and we therefore assume that the mite species found in D. cervina is parasitic, like other Leptus larvae. Southcott (1992) described Leptus millipedius from julid millipedes, but this is the first record of a parasitic prostigmatan mite from a paradoxosomatid millipede. The only record of a mite from Paradoxosomatidae concerns the widespread Oxidus gracilis (C. L. Koch, 1847) which was reported as associated with Cosmolaelaps hortensis Ishikawa, 1986 (Mesostigmata, family Laelapidae) (Ishikawa 1986).

Golovatch and Enghoff (1994) reported one broken male of “Desmoxytes sp.” from Phuket Province, Thailand. According to the remarks of Golovatch and Enghoff (1994), the gonopod characters of this specimen were similar to D. delfae, but the paraterga showed a higher degree of elevation. We examined this specimen again and found it to share gonopod and other characters with D. cervina. We therefore treat “Desmoxytes sp.” as D. cervina.

D. delfae at Wat Tham Sue (Tiger Cave), Krung Ching Waterfall, Khiri Rat Pattana Bureau of Monks (Wat Khao Poon); D. corythosaurus sp. n. at Ban Song Phi Nong.

Male (CUMZ), THAILAND, Surat Thani Province, Phanom District, Ban Song Phi Nong, huge limestone mountain, 8°50'51"N, 98°44'16"E, ca. 74 m a.s.l., 7 August 2014, leg. C. Sutcharit, R. Srisonchai and ASRU members.

5 males, 1 female (CUMZ), 1 male (ZMUC), same data as holotype.

not paratypes, all from THAILAND, Surat Thani Province, Phanom District: 1 male, 2 females (CUMZ), Wat Tham Wararam, 8°53'07"N, 98°40'01"E, ca. 51 m a.s.l., 5 August 2014, leg. C. Sutcharit, R. Srisonchai and ASRU members. 1 male, 1 female (CUMZ), Wat Tham Wararam, 8°53'07"N, 98°40'01"E, ca. 51 m a.s.l., 6 August 2016, leg. C. Sutcharit, R. Srisonchai and ASRU members. 1 male, 1 broken female (CUMZ), Wat Tham Wararam, 8°53'07"N, 98°40'01"E, ca. 51 m a.s.l., 1 August 2017, leg. C. Sutcharit and A. Pholyotha and ASRU members. 2 males, 1 female (CUMZ), Tham Nam Lod, near Anurak Community Lodge Resort, big limestone mountain, 8°52'43"N, 98°40'50"E, ca. 51 m a.s.l., 7 August 2014, leg. C. Sutcharit, R. Srisonchai and ASRU members.

The name is a Latin noun in apposition, referring to the similarity of the lamina lateralis (ll) to the crest-liked structure on the head of the dinosaur genus Corythosaurus.

Body dark brown to black; paraterga with brown or black patches contrasting against whitish at base and along the edges; metaterga 2–18 with rows of 2+2 anterior and 2+2 posterior tubercles. Similar in these respects to D. terae, but differing by having paraterga much longer and higher; sternal lobe between male coxae 4 subtrapeziform; male femora 5 and 6 modified; lamina lateralis (ll) apically crest-like; distal lobe with one very long lamella; indentation between distal lobe (dlm) and broad lobe (blm) inconspicuous.

SIZE: Length 32–33 mm (male), 33–34 mm (female); width of midbody metazona ca. 2.3 mm (male), 3.0 mm (female). Width of head < collum < body ring 2 < 3 = 4 < 5–16, thereafter body gradually tapering towards telson.

COLOUR (Fig. 23A–D): In life with body brownish black; antenna and head dark brown (except distal part of antennomere 7 and antennomere 8 whitish); metaterga and surface below paraterga brownish black; paraterga whitish, dorsally with brown patches in the middle; legs, sterna and epiproct brown; a few basal podomeres sometimes whitish.

ANTENNAE (Fig. 24D): Moderately long and slender, reaching to the posterior end of body ring 6 (male) and 5 (female) when stretched dorsally.

COLLUM (Fig. 24A): With 1 transverse anterior row of 3+3 setae; paraterga of collum low, elevated at ca. 10°–15°, directed caudolaterad, with two distinct notches on lateral margin.

TEGUMENT: Moderately shining and smooth; prozona finely shagreened; collum, metaterga, surface below paraterga, sterna and epiproct smooth; lateral surface at base of paraterga with wrinkles.

METATERGA (Fig. 24A–C): With 2 transverse rows of setae and tubercles, mostly inconspicuous; metaterga 2–18 with 2+2 anterior and 2+2 posterior tubercles; metatergum 19 with 2+2 anterior and 2+2 posterior setae.

PARATERGA (Fig. 24E, F): Directed caudolaterad on body rings 2–17, elevated at ca. 30° (male) 25° (female); directed increasingly caudad on body rings 18 and 19; tip of paraterga in female slightlty curved caudad; anterior margin with 2 distinct notches, without a tiny denticle near the tip.

TELSON (Fig. 25C–G): Epiproct: tip subtruncate; lateral setiferous tubercles and apical tubercles inconspicuous. Hypoproct subtrapeziform; caudal margin round, with very small and inconspicuous setiferous tubercles.

STERNA (Fig. 26): Cross-impressions shallow. Sternal lobe between male coxae 4 subtrapeziform; tip usually slightly round (in some specimens subemarginate), base broad and stout.

LEGS (Fig. 25H–J): Long and slender. Male femora 5 and 6 strongly humped ventrally in middle portion (hump of male femora 6 more developed than 5).

GONOPODS (Figs 27, 28): Coxa (cx) longer than prefemur. Cannula (ca) somewhat stout. Telopodite erect. Prefemur (pfe) ca. 2/3 as long as femur. Femur (fe) quite long and slender. Mesal sulcus (ms) and lateral sulcus (ls) conspicuous, very deep. Postfemur (pof) conspicuous, ventrally narrow and short. Solenophore (sph) well-developed: lamina lateralis (ll) conspicuous, apically crest-like, quite thin; anterolaterally with a wide and conspicuous furrow: lamina medialis (lm) well-developed; process (plm) very short; distal lobe (dlm) very long and broad, indentation between distal lobe (dlm) and broad lobe (blm) inconspicuous; broad lobe (blm) moderately thick. Solenomere (sl) long.

This species is known only from a narrow distribution range in Phanom district. We consider D. corythosaurus sp. n. to be endemic for Surat Thani Province, Thailand.

The shape of the sternal lobe between male coxae 4 is variable: the tip is emarginate in the populations from Wat Tham Wararam and Tham Nam Lod, whereas specimens from the type locality have a truncate tip. The new species shares a similar shape of gonopodal solenophore with D. terae.

This species is almost impossible to find at first glance. We collected all specimens that were found on the humid rock walls by using flashlight. It blended in perfectly with the brown or black rock, this way probably avoiding being detected by predators.

Desmoxytes cervina (brown morph) at Ban Song Phi Nong, was collected from rock walls, same habitat as the new species.

Holotype. Male (NHMUK), THAILAND, Bukit Besar, on leaves in clearing, late evening, 3 September 1901.

1 male, 1 female (NHMUK), 1 male (NBC), THAILAND, Bukit Besar, Nawnchila, crawling on low foliage in clearing, 2500 feet a.s.l., 29 September 1901.

Holotype (D. rubra): Male (ZMUC), THAILAND, Satun Province, Thale Ban National Park, lowland rainforest, on vegetation and under bark, 6°42'N, 100°10'E, ca. 400 m a.s.l., 20 October 1991, leg. M. Andersen, O. Martin, N. Scharff.

Paratypes (D. rubra): 6 males, 5 females (ZMUC), same data as holotype.

all from THAILAND, Krabi Province: 1 female (CUMZ), Mueang Krabi District, Huai To Waterfall, 8°14'27"N, 98°54'51"E, ca. 110 m a.s.l., 16 January 2006, leg. S. Panha and ASRU members. 1 male missing right gonopod (CUMZ), Mueang Krabi District, Wat Tham Sue (Tiger Cave), valley behind Tiger Cave, 8°07'39"N, 98°55'27"E, ca. 85 m a.s.l., 7 October 2009, leg. S. Panha and ASRU members. 1 male (CUMZ), Mueang Krabi District, Wat Tham Sue (Tiger Cave), valley behind Tiger Cave, 8°07'39"N, 98°55'27"E, ca. 85 m a.s.l., 28 April 2014, leg. C. Sutcharit, R. Srisonchai and ASRU members. 5 males, 2 females (CUMZ), Mueang Krabi District, Wat Tham Sue (Tiger Cave), valley behind Tiger Cave, 8°07'39"N, 98°55'27"E, ca. 85 m a.s.l., 9 July 2017, leg. C. Sutcharit, R. Srisonchai and ASRU members. 1 male, 1 female (CUMZ), Mueang Krabi District, Wat Tham Sue (Tiger Cave), valley behind Tiger Cave, 8°07'39"N, 98°55'27"E, ca. 85 m a.s.l., 25 July 2017, leg. C. Sutcharit, R. Srisonchai and ASRU members.

Nakhon Si Thammarat Province: 2 broken males (CUMZ), Nopphitam District, Krung Ching Waterfall, 8°43'27"N, 99°40'07"E, ca. 171 m a.s.l., 28 October 2006, leg. S. Panha and ASRU members. 1 female (CUMZ), Thung Song District, Talod Cave Park (Talod Cave), 8°09'32"N, 99°40'42"E, ca. 73 m a.s.l., 5 July 2017, leg. C. Sutcharit, R. Srisonchai and ASRU members. 2 males, 1 female (CUMZ), Thung Song District, Weruwan Bureau of Monks (Tham Rad), 8°02'48"N, 99°43'43"E, ca. 82 m a.s.l., 5 July 2017, leg. C. Sutcharit, R. Srisonchai and ASRU members.

Phatthalung Province: 2 males,1 female (CUMZ), Khao Chaison District, Khao Chaison Hot Spring, 7°26'59"N, 100°07'48"E, ca. 37 m a.s.l., 12 January 2009, leg. S. Panha and ASRU members. 1 broken male missing gonopods, 2 females (CUMZ), Khao Chaison District, Khao Chaison Hot Spring, 7°26'59"N, 100°07'48"E, ca. 37 m a.s.l., 13 January 2009, leg. C. Sutcharit and ASRU members. 1 female (CUMZ), Khuan Khanun District, Tham Wang Thong, 7°40'57"N, 100°00'58"E, ca. 45 m a.s.l., 12 January 2009, leg. C. Sutcharit and ASRU members. 3 males, 1 female (CUMZ), Khuan Khanun District, Tham Wang Thong, 7°40'57"N, 100°00'58"E, ca. 45 m a.s.l., 6 July 2017, leg. C. Sutcharit and ASRU members. 3 males, 3 females (CUMZ), Kong Ra District, Khao Phaya Hong, 7°27'46"N, 99°57'50"E, ca. 55 m a.s.l., 6 July 2017, leg. C. Sutcharit, R. Srisonchai and ASRU members.

Satun Province: 1 male (ZMUC), Thale Ban National Park, lowland rainforest, 6°42'37"N, 100°10'09"E, ca. 93 m a.s.l., 15–18 October 2003, leg. ATOL expedition (ZMUC staff). 7 males, 2 females (CUMZ), Thung Wa District, Tham Khan Ti Phol, 7°05'11"N, 99°47'53"E, ca. 82 m a.s.l., 8 July 2017, leg. C. Sutcharit, R. Srisonchai and ASRU members. 26 males, 4 females (CUMZ), 2 males, 1 female (ZMUC), 1 male (ZMUM), 1 male (NHMW) ,1 male (NHMUK), Thung Wa District, Tham Khan Ti Phol, 7°05'11"N, 99°47'53"E, ca. 82 m a.s.l., 7 July 2017, leg. C. Sutcharit, R. Srisonchai and ASRU members. 2 males, 2 females (CUMZ), Khuan Don District, Thale Ban National Park, Tham Tone Din (Tone Din Cave), 6°43'35"N, 100°09'45"E, ca. 154 m a.s.l., 7 July 2017, leg. S. Sutcharit, R. Srisonchai and ASRU members. 1 female (CUMZ), La-ngu District, limestone mountain near Ao Noon (Mu Ko Petra National Park), 6°50'17"N, 99°45'41"E, ca. 37 m a.s.l., 31 August 2015, leg. C. Sutcharit, R. Srisonchai and ASRU members. 2 males (CUMZ), La-ngu District, limestone mountain near La-ngu Subdistrict, 6°53'41"N, 99°46'49"E, ca. 18 m a.s.l., 17 July 2017, leg. P. Danaisawadi.

Songkhla Province: 1 male missing gonopods (CUMZ), Hat Yai District, Ton Nga Chang Waterfall, 6°56'53"N, 100°14'03"E, ca. 157 m a.s.l., 12 January 2009, leg. S. Panha and ASRU members. Many broken and mixed specimens (CUMZ), Hat Yai District, Ton Nga Chang Waterfall, 6°56'53"N, 100°14'03"E, ca. 157 m a.s.l., 13 December 2011, leg. S. Panha and ASRU members. 4 males, 4 females (CUMZ), Sa Dao District, Khao Wong Pra Chan Bureau of Monks, 6°42'38"N, 100°16'34"E, ca. 100 m a.s.l., 7–8 July 2017, leg. C. Sutcharit, R. Srisonchai and ASRU members. 2 females (CUMZ), Sa Dao District, Tham Nang Phaya Lued Kao Bureau of Monks, 6°44'26"N, 100°15'27"E, ca. 124 m a.s.l., 7 July 2017, leg. C. Sutcharit, R. Srisonchai and ASRU members.

Surat Thani Province: 2 males, 1 female (CUMZ), Wiang Sa District, Khiri Rat Pattana Bureau of Monks (Wat Khao Poon), 8°31'38"N, 99°22'59"E, ca. 49 m a.s.l., 4 July 2017, leg. C. Sutcharit, R. Srisonchai and ASRU members. 2 males, 1 female (CUMZ), Tham Phannara District, Wat Tham Kanlaya Namit, 8°30'49"N, 99°22'53"E, ca. 62 m a.s.l., 4 July 2017, leg. C. Sutcharit, R. Srisonchai and ASRU members.

Trang Province: 3 males, 3 females, 2 juveniles (CUMZ), Palian District, Tham Khao Ting, 7°09'31"N, 99°48'10"E, ca. 42 m a.s.l., 31 August 2015, leg. C. Sutcharit, R. Srisonchai and ASRU members. 9 males, 2 females (CUMZ), Palian District, Tham Khao Ting, 7°09'31"N, 99°48'10"E, ca. 42 m a.s.l., 8 July 2017, leg. C. Sutcharit, R. Srisonchai and ASRU members.

Yala Province: 1 male (ZMUC), Bang Lang National Park, lowland rainforest, 6°4'N, 101°11'E, ca. 400 m a.s.l., 20 October 1991, leg. M. Andersen, O. Martin, N. Scharff.

Differs from congeners in the combination of the following characters; sternal lobe between male coxae 4 thick and stout, round/ subtrapeziform/ subrectangular; lamina lateralis (ll) swollen, round crest-like, laterally with a distinct and wide furrow, mesally with deep subsided surface; process (plm) of lamina medialis short, distally curving dorsad, tip blunt.

Thailand, Bukit Besar [Thale Ban National Park, Khuan Don District, Satun Province].

The redescription hereunder is modified from Jeekel (1964), and Golovatch and Enghoff (1994). We ‘harmonised’ descriptions of all morphological characters and added some morphological characteristics from additional collected specimens.

SIZE: Length 21–24 mm (male), 23–27 mm (female); width of midbody metazona ca. 1.8 mm (male), 2.3 mm (female). Width of head ≥ collum < body ring 2 < 3 < 4 < 5–16, thereafter body gradually tapering towards telson.

COLOUR (Figs 29, 30A–C): In life body bright orange or brownish orange (newly moulted adults pale pink); head, paraterga, surface below paraterga and epiproct yellowish orange; metaterga bright orange; antenna brownish orange or blackish orange (except antennomere 7 blackish, distal part of antennomere 7 and antennomere 8 whitish); legs brownish orange or brownish black; a few basal podomeres whitish yellow; sterna whitish yellow or orange; prozona and metazona (metaterga) with wide black stripe, conspicuous on rings 4–19. Colour in alcohol: after 116 years changed to white, after 26 years changed to brownish white.

ANTENNAE (Fig. 31D): Moderately long and slender, reaching to body ring 6 (male) and 4–5 (female) when stretched dorsally.

COLLUM (Fig. 31A): With 1 transverse anterior row of 3+3 setae; paraterga of collum low, almost horizontal, directed almost caudad, with two setiferous notches on lateral margin.

TEGUMENT: Strongly shining and smooth; prozona finely shagreened; collum, metaterga, paraterga, sterna and epiproct smooth; surface below paraterga coarsely microgranulate.

METATERGA (Fig. 31A–C): With 2 transverse rows of small tubercles; metaterga 2–19 with 2+2 anterior and 2+2 posterior tubercles.

PARATERGA (Fig. 31E, F): Directed caudolaterad on body rings 2–17, elevated ca. 10°–20° above the horizontal plane (ca. 20° in male, ca. 10° in female), directed increasingly caudad on body rings 18 and 19; anterior margin with 2 distinct notches, on lateral margin of body rings 9, 10, 12, 13, 15–18 with tiny denticle near the tip.

TELSON (Fig. 32C–G): Epiproct: tip truncate; lateral setiferous tubercles usually conspicuous (in some specimens inconspicuous); apical tubercles inconspicuous. Hypoproct subtriangular; caudal margin round and narrow, with inconspicuous setiferous tubercles.

STERNA (Fig. 33): Cross-impressions shallow. Sternal lobe between male coxae 4 round/ subtrapeziform/ subrectangular (varies within population); erect, stout, thick, and broad when seen in ventral view; tip subtruncate/ round/ emarginate (varies within population).

LEGS (Fig. 32H–J): Long and slender. Male femora 5 and 6 strongly humped ventrally in middle portion.

GONOPODS (Figs 34, 35): Coxa (cx) longer than prefemur. Cannula (ca) long and slender. Prefemur (pfe) ca. 2/3 as long as femur. Femur (fe) quite long. Mesal sulcus (ms) and lateral sulcus (ls) conspicuous, deep and wide. Postfemur (pof) conspicuous, ventrally narrow, and short. Solenophore (sph) well-developed: lamina lateralis (ll) swollen, round crest-like, laterally with a distinct furrow, mesally with deep subsided surface; ventral ridge (vrl) conspicuous: lamina medialis (lm) well-developed; process (plm) short, distally curving dorsad, tip blunt; distal lobe (dlm) distally with two lamellae, mesal lamella thin and smaller than lateral one; broad lobe (blm) somewhat thick, distinctly separated from distal lobe (dlm) by a deep and wide indentation. Solenomere (sl) long.

Desmoxytes delfae is known from several provinces in southern Thailand. All new specimens were collected by us from limestone habitats (the recorded locations in previous papers are also limestone); most specimens were seen crawling on leaf litter and climbing on branches of trees (Fig. 30D).

The type locality, Bukit Besar, may be part of what is now Thale Ban National Park in Khuan Don District, Satun Province, and refers to the big mountain which is probably Khao Chin (ca. 2500 ft. or 756 m). Specimens collected by us from Thale Ban National Park may thus be topotypes. The other paratype locality (Bukit Besar, Nawnchila) has not been exactly located, but it is probably near Thale Ban National Park (Thailand–Malaysia border), possibly close to the type locality.

We assume that D. delfae is distributed mainly in Thailand and possibly south to Malaysia near the Thailand–Malaysia border.

This species was reported as endemic for Thailand (Decker 2010), and we would agree that it should be regarded as endemic for the southern part of Thailand due to its narrow distribution. However, two males of D. delfae were reported from Khaosok National Park in west of Surat Thani Province by Decker (2010); it is probable that the specimens from this location belong to another species because all the specimens of D. delfae which we have seen are from an area in south Thailand (Krabi, east of Surat Thaini, Nakhon Si Thammarat, Phatthalung, Satun, Songkhla, and Yala Provinces). Furthermore, Decker (2010) also identified one male, which was collected from Nakhon Si Thammarat Province (Lan Saka District, Khao Luang National Park, near Karom Waterfall) as D. rubra. Re-examination of those specimens in MHNG is necessary to evaluate the distribution of this species.

The remarkable and vivid bright orange colouration is clearly aposematic.

Golovatch and Enghoff (1994) distinguished D. rubra from D. delfae based on D. rubra having 1+1 anterior and 2+2 posterior metatergal tubercles, the mid-dorsal (axial) line traceable, the sternal lobe between male coxae 4 roundly subtriangular and lamina medialis (lm) more strongly produced mesally than dorsally. After examination of all type material and new specimens of both D. delfae and “D. rubra” collected by us, we found that:

– There is a variation in the size of tubercles on metaterga (metaterga with two rows of 2+2 anterior and 2+2 posterior tubercles, lateral tubercles of anterior row in some specimens (tiny and very inconspicuous).

– All specimens are without mid-dorsal line.

– The sternal lobe between male coxae 4 is highly variable in shape, even within populations, as round/ subtrapeziform/ subrectangular; we found this variation in both D. delfae and “D. rubra” specimens. Its tip also varies as subtruncate/ round/ emarginate.

– SEM images clearly show that specimens of these two nominal species have identical gonopods, especially in details of lamina lateralis and lamina medialis.

Due to this variation, we have synonymised D. rubra under D. delfae.

Jeekel (1964) described this species as lacking a tiny denticle near the tip of paraterga on the lateral margin of rings 9, 10, 12, 13, 15–18, and collum as having 2 rows of 3+3 conspicuous setae (anterior row) and 1?+1? inconspicuous tubercles (posterior row). All specimens studied by us have a tiny denticle near the tip (conspicuous in some specimens, inconspicuous in others), and we regard this character as variable within populations.

For D. rubra, Golovatch and Enghoff (1994) described the colour of alcohol-preserved specimens as bright pinkish, that of living specimens as bright red, collum with 3 rows of setae (anterior conspicuous, intermediate and posterior inconspicuous), mid-dorsal line traceable. Based on the re-examination of type material of D. rubra and examination of newly collected specimens we have found that D. rubra (= D. delfae) exhibits:

– Specimens in life with bright orange colouration, newly moulted adult stage pinkish or pinkish orange, late adult stage reddish orange or dark orange. As Golovatch and Enghoff (1994) reported that living specimens have a bright red colour, it is possible that the type specimens of D. rubra were collected at late adult stage (red = reddish orange?).

– Collum with one row of setae (3+3 anterior setae), intermediate and posterior rows absent. Therefore, we here report collum with only one row of setae (3+3 anterior setae).

– All specimens without mid-dorsal line.

– Sternal lobe between male coxae 4 varies within population, round/ subtrapeziform/ subrectangular.

As we mentioned above, this species shows high variability in morphology, e.g., colour, rows of setae on collum, size of metatergal tubercles, occurrence of a tiny denticle near tip of paraterga, shape of sternal lobe between male coxae 4. All variations are typically present within a population. Although there are deviations in several morphological characters, interestingly, gonopod characters of all specimens are quite stable, looking exactly the same in details.

Desmoxytes cervina in several places, D. terae at Tham Tone Din, D. flabella sp. n. at Tham Khao Ting and Tham Khan Ti Phol.

Male (CUMZ), THAILAND, Chiang Mai Province, Fang District, Doi Angkhang, near Royal Agricultural Station, 19°54'26"N, 99°02'26"E, ca. 1426 m a.s.l., 12 August 2014, leg. N. Likhitrakarn.

2 males, 2 females (CUMZ), same data as holotype. 1 male, 2 females (CUMZ), THAILAND, Chiang Mai Province, Chiang Dao District, Wat Tham Krab, 19°33'32"N, 99°03'47"E, ca. 622 m a.s.l., 25 October 2015, leg. C. Sutcharit, R. Srisonchai, T. Seesamut and A. Pholyotha.

THAILAND, Chiang Mai Province, Fang District, Doi Angkhang, near Royal Agricultural Station.

Differs from all other Desmoxytes species by the combination of the following characters: paraterga knife-like; lateral sulcus (ls) of gonopod shallow; lamina lateralis (ll) separated into two ridges by a deep and wide furrow; process (plm) of lamina medialis long and thin, lamellar, tip dentate or crenate; distal lobe (dlm) of lamina medialis quite long, tip directed ventroanteriad; caudal margin of hypoproct concave or truncate.

(updated from Srisonchai et al. 2016). SIZE: Length 26–34 mm (male), 30–34 mm (female); width of midbody metazona ca. 2.5 mm (male), 3.0 mm (female). Width of head < collum < body ring 2 = 3 < 4 ≤ 5 < 6–16, thereafter body gradually tapering toward telson.

COLOUR: In life with body dark brown; paraterga bright pink; head, metaterga and surface below paraterga dark brown; antenna (except distal part of antennomere 7 and antennomere 8 whitish), leg, sterna and epiproct brown; a few basal podomeres pinkish brown or brown. Colour in alcohol: after two years changed to dark brown or pale brown.

ANTENNAE: Quite short, reaching to body ring 3 or 4 (male), and 3 (female) when stretched dorsally.

COLLUM: With 3 transverse rows of setiferous tubercles, 3+3 anterior, 1+1 posterior setae (posterior setae inconspicuous); paraterga of collum low, elevated at ca. 20°–30°, directed almost caudolaterad, with two inconspicuous setiferous notches on lateral margin.

TEGUMENT: Quite dull, but slightly shining; prozona finely shagreened; metaterga and surface below paraterga coarsely microgranulate; collum, paraterga, sterna and epiproct smooth.

METATERGA: With 2 transverse rows of setiferous tubercles; metaterga 2–18 with 2+2 anterior and 2+2 posterior tubercles; metatergum 19 with 2+2 anterior and 2+2 posterior setae.

PARATERGA: Directed caudolaterad on body rings 2–16, elevated at ca. 45° (male) 40° (female); directed increasingly caudad on body rings 17, 18 and 19; anterior margin with 2 distinct notches, on lateral margin of body rings 9, 10, 12, 13, 15–18 with tiny denticle near the tip.

TELSON: Epiproct: tip truncate; lateral setiferous tubercles conspicuous, small; apical tubercles inconspicuous. Hypoproct subtrapeziform; caudal margin quite concave or truncate, with inconspicuous setiferous tubercles.

STERNA: Cross-impressions shallow. Sternal lobe between male coxae 4 swollen, subrectangular, flat when seen in lateral view, tip truncate.

LEGS: Long and slender. Male femora 5 and 6 slightly stout, moderately humped ventrally in middle part.

GONOPODS (Fig. 36): Coxa (cx) longer than prefemur. Cannula (ca) slender. Telopodite quite stout. Prefemur (pfe) half to 2/3 as long as femur. Femur (fe) slightly stout. Mesal sulcus (ms) very deep and narrow, lateral sulcus (ls) shallow (= “poorly developed” in Srisonchai et al. 2016). Postfemur (pof) conspicuous, ventrally narrow. Solenophore (sph) well-developed: lamina lateralis (ll) swollen, laterally with a conspicuous, deep and wide furrow (= sulcus) separating ll into two ridges (inner ridge larger than outer one): lamina medialis (lm) well-developed; process (plm) lamellar, slightly short and thin, base long, tip dentate or crenate, indistinctly separated from distal lobe; distal lobe (dlm) quite long, tip directed ventroanteriad; broad lobe (blm) thick, indentation between broad lobe (blm) and distal lobe (dlm) inconspicuous. Solenomere (sl) quite long, distally twisted.

Known only from the type locality and nearby areas. This species seems to be rare because we made intensive surveys again in 2015 and 2016, no further specimens were found. As mentioned by Srisonchai et al. (2016), D. des is known only from two localities (Doi Angkhang and Wat Tham Krab), and we consider it to be endemic to Thailand.

This species exhibits some variation in the gonopods: the tip of process (plm) of lamina lateralis is dentate in some specimens, crenate in others. Desmoxytes des is easy to discriminate from other dragon millipedes by the distinct shape of paraterga and unique gonopod characters.

None known.

Corrections to Srisonchai et al. (2016).Srisonchai et al. (2016, pp. 99–103) wrote in the description of this species that paraterga (including paraterga of collum) are directed dorsolaterad at ca. 30°. They are in fact directed caudolaterad and are elevated at ca. 45° as stated in the updated redescription above. Moreover, Srisonchai et al. also described the surface of metaterga as finely shagreened, but we now regard it as being coarsely microgranulate.

Male (CUMZ), THAILAND, Chanthaburi Province, Kaeng Hang Maeo District, Khao Wong Kot Cave, 12°53'53"N, 101°49'00"E, ca. 53 m a.s.l., 4 August 2016, leg. S. Panha, P. Tongkerd ans ASRU members.

13 males, 5 females (CUMZ), same data as holotype. 3 males, 4 females (CUMZ), 2 males, 1 female (ZMUC), 1 male (NHMW), THALAND, Rayong Province, Khao Chamao District, Wat Tham Suwan Phupha, 12°59'16"N, 101°39'32"E, ca. 64 m a.s.l., 8 August 2017, leg. P. Tongkerd and ASRU members.

not paratypes, all from THAILAND, Chantaburi Province: 1 male, 1 female (CUMZ), Kaeng Hang Maeo District, Khao Wong Kot Cave, 12°53'53"N, 101°49'00"E, ca. 53 m a.s.l., 15 September 2009, leg. S. Panha and ASRU members. 1 male, 1 female (CUMZ), Kaeng Hang Maeo District, Khao Wong Kot Cave, 12°53'53"N, 101°49'00"E, ca. 53 m a.s.l., 1 October 2009, leg. S. Panha and ASRU members. 2 males, 1 female (CUMZ), Kaeng Hang Maeo District, near Khao Wong Kot Cave, 12°53'53"N, 101°49'00"E, ca. 53 m a.s.l., 15 October 2010, leg. S. Panha and ASRU members. 1 male, 2 females (CUMZ), Kaeng Hang Maeo District, near Khao Wong Kot Cave, 12°53'53"N, 101°49'00"E, ca. 53 m a.s.l., 24 October 2010, leg. S. Panha and ASRU members. 4 males, 4 females, 2 juveniles (CUMZ), Kaeng Hang Maeo District, Khao Wong Kot Cave, 12°53'53"N, 101°49'00"E, ca. 53 m a.s.l., 17 October 2015, leg. C. Sutcharit and R. Srisonchai. 1 female (CUMZ), Kaeng Hang Maeo District, Khao Wong Kot Cave, 12°53'53"N, 101°49'00"E, ca. 53 m a.s.l., 8 August 2017, leg. S. Panha, P. Tongkerd ans ASRU members. 5 males, 3 females (CUMZ), Kaeng Hang Maeo District, Khao Sip Ha Chan National Park, 13°10'33"N, 102°00'09"E, ca. 118 m a.s.l., 7 October 2010, leg. S. Panha and ASRU members. 2 males, 1 female (CUMZ), Khlung District, Makok Waterfall, 12°35'14"N, 102°15'21"E, ca. 58 m a.s.l., 3 September 2007, leg. ASRU members. 1 male, 1 female (CUMZ), Khlung District, Makok Waterfall, 12°35'14"N, 102°15'21"E, ca. 59 m a.s.l., 3 September 2007, leg. ASRU members. 3 males, 3 females, 4 females (CUMZ), Khlung District, Makok Waterfall, 12°35'14"N, 102°15'21"E, ca. 58 m a.s.l., 10 August 2014, leg. ASRU members. 5 males, 3 females (CUMZ), Mueang Chantaburi District, Phlio Waterfall, 12°31'44"N 102°10'57"E, ca. 104 m a.s.l., 19 October 2015, leg. S. Panha and ASRU members. 2 males, 2 females (CUMZ), Tha Mai District, Wat Khao Su Kim (Khao Su Kim Temple), 12°45'47"N, 102°01'56"E, ca. 148 m a.s.l., 29 September 2009, leg. S. Panha and ASRU members. 3 males, 5 females (CUMZ), Tha Mai District, Wat Khao Su Kim (Khao Su Kim Temple), 12°45'47"N, 102°01'56"E, ca. 148 m a.s.l., 14 October 2010, leg. S. Panha and ASRU members. 2 males, 2 females (CUMZ), Tha Mai District, Wat Khao Su Kim (Khao Su Kim Temple), 12°45'47"N, 102°01'56"E, ca. 148 m a.s.l., 6 August 2011, leg. S. Panha and ASRU members. 2 males, 1 female, 1 juvenile (CUMZ), Tha Mai District, Wat Khao Su Kim (Khao Su Kim Temple), 12°45'47"N, 102°01'56"E, ca. 148 m a.s.l., 8 August 2017, leg. S. Panha, P. Tongkerd and ASRU members.

Chonburi Province: 2 males, 3 females (CUMZ), Bo Thong District, Wat Tham Khao Cha-ang Oune, 13°12'35"N, 101°39'09"E, ca. 151 m a.s.l., 15 September 2009, leg. ASRU members. 2 males, 3 females (CUMZ), Bo Thong District, Wat Tham Khao Cha-ang Oune, 13°12'35"N, 101°39'09"E, ca. 151 m a.s.l., 15 October 2010, leg. ASRU members. 2 males (CUMZ), Bo Thong District, Wat Tham Khao Cha-ang Oune, 13°12'35"N, 101°39'09"E, ca. 151 m a.s.l., 24 September 2012, leg. S. Panha and ASRU members. 2 males, 2 females (CUMZ), Bo Thong District, Wat Tham Khao Cha-ang Oune, 13°12'35"N, 101°39'09"E, ca. 151 m a.s.l., 6 July 2016, leg. A. Pholyotha and ASRU members. 1 male, 1 female (CUMZ), Bo Thong District, Wat Tham Khao Cha-ang Oune, 13°12'35"N, 101°39'09"E, ca. 151 m a.s.l., 25 October, leg. ASRU members.

Rayong Province: 1 male, 1 female (CUMZ), Khao Chamao District, Wat Tham Watana Monkhol, 13°05'45"N, 101°36'28"E, ca. 76 m a.s.l., Unknown date, leg. S. Panha and ASRU members. 3 males (CUMZ), Khao Chamao District, Wat Tham Khao Loy (Wat Ma Duae), 13°03'26"N, 101°36'28"E, ca. 71 m a.s.l., 5 September 2008, leg. S. Panha and ASRU members. 1 male, 1 female (CUMZ), Khao Chamao District, Wat Tham Khao Loy (Wat Ma Duae), 13°03'26"N, 101°36'28"E, ca. 71 m a.s.l., 23 October 2010, leg. S. Panha and ASRU members. 1 male, 3 females (CUMZ), Khao Chamao District, Wat Tham Khao Loy (Wat Ma Duae), 13°03'26"N, 101°36'28"E, ca. 71 m a.s.l., 9 November 2013, leg. S. Panha and ASRU members. 1 male, 1 female (CUMZ), Khao Chamao District, Tham Khao Pratun Monastery, 13°07'26"N, 101°35'52"E, ca. 107 m a.s.l., 24 October 2010, leg. S. Panha and ASRU members. 1 male, 1 female (CUMZ), Khao Chamao District, Khlong Pra Kang Waterfall, 12°55'59"N, 101°42'58"E, ca. 69 m a.s.l., 15 September 2009, leg. S. Panha and ASRU members. 1 male, 1 female (CUMZ), Khao Chamao District, Tham Khao Boath Bureau of Monks, 13°02'13"N, 101°38'08"E, ca. 102 m a.s.l., 23 October 2010, leg. S. Panha and ASRU members. 2 males, 2 females (CUMZ), Khao Chamao District, Wat Nong Tha Khian, 12°57'49"N, 101°40'24"E, ca. 64 m a.s.l., 5 September 2008, leg. C. Sutcharit and ASRU members. 1 male, 1 female (CUMZ), Khao Chamao District, Wat Tham Khao Chamao, 23 October 2008, leg. C. Sutcharit and ASRU members.

Sa Kaeo Province: 1 male, 1 female (CUMZ), Khlong Hat District, Phet Pho Thong Cave, 13°24'50"N, 102°19'33"E, ca. 240 m a.s.l., 28 October 2010, leg. C. Sutcharit and ASRU members. 1 male, 1 female (CUMZ), Khao Chakan District, near Wat Tham Khao Chakan, 13°39'40"N, 102°05'11"E, ca. 75 m a.s.l., 28 August 2014, leg. S. Panha and ASRU members. 2 males, 1 female (CUMZ), Khlong Hat District, Phet Pho Thong Cave, 13°24'50"N, 102°19'33"E, ca. 240 m a.s.l., 28 August 2014, leg. S. Panha and ASRU members. 1 male, 3 females (CUMZ), Khao Chakan District, near Wat Tham Khao Chakan, 13°39'40"N, 102°05'11"E, ca. 75 m a.s.l., 3 September 2015, leg. S. Panha and ASRU members.

Body black or brownish black; collum with 3 transverse rows of setae and setiferous tubercles (4+4 anterior setae, 1+1 intermediate setae and 2+2 posterior tubercles); metaterga 2–16 with two rows of 2+2 (anterior) setiferous cones and 2+2 (posterior) setiferous spines; ventral ridge (vrl) of lamina lateralis conspicuous; process (plm) of lamina medialis long, directed almost mesad; distal lobe (dlm) distally with two distinct lamellae. Similar in these respects to D. planata, but differs from that species by having paraterga yellow to orange and hypoproct subtriangular with conspicuous setiferous tubercles.

“Euros” (noun in apposition) is the name of the ancient Greek god of the east wind; the name refers to the occurrence of this species in the eastern part of Thailand.

SIZE: Length 25–27 mm (male), 28–29 mm (female); width of midbody metazona ca. 1.6 mm (male), 2 mm (female). Width of head < collum = body ring 2 < 3 = 4 < 5–16, thereafter body gradually tapering towards telson.

COLOUR (Fig. 37A–D): In life with body dark or brownish black; paraterga yellow to orange; head, antenna, metaterga and surface below paraterga dark brown (except distal part of antennomere 7 and antennomere 8 whitish); epiproct, sterna and a few basal podomeres brown to whitish; legs otherwise brown.

ANTENNAE (Fig. 38D): Moderately long and slender, reaching to body ring 6 (male) and 5 (female) when stretched dorsally.

COLLUM (Fig. 38A): With 3 transverse rows of setae and setiferous tubercles, 4+4 anterior setae, 1+1 intermediate setae and 2+2 posterior tubercles (lateral seta in anterior row located almost at base of paraterga in some specimens); paraterga of collum low, elevated at ca. 15°–20°, directed caudolaterad, with one inconspicuous notch on lateral margin.

TEGUMENT: Quite dull, slightly shining; collum and metaterga microgranulate; prozona finely shagreened; surface below paraterga finely microgranulate; sterna and epiproct smooth.

METATERGA (Fig. 38A–C): With 2 transverse rows of setiferous tubercles, cones and spines; metaterga 2–8 with 2+2 anterior cones and 2+2 posterior spines; metaterga 9–16 with 2+2 anterior cones and 2+2 posterior spines; metaterga 17–18 with 2+2 anterior and 2+2 posterior cones; metatergum 19 with 2+2 anterior and 2+2 posterior tubercles.

PARATERGA (Fig. 38E, F): Directed caudolaterad on body rings 2–17, elevated at ca. 45° (male) 40° (female); directed increasingly caudad on body rings 18 and 19; anterior margin with 2 distinct notches, on lateral margin of body rings 9, 10, 12, 13, 15–18 with tiny denticle near the tip.

TELSON (Fig. 39C–G): Epiproct: tip emarginate; lateral setiferous tubercles and apical tubercles conspicuous. Hypoproct subtriangular; caudal margin subtriangular, with conspicuous setiferous tubercles.

STERNA (Fig. 40): Cross-impressions shallow. Sternal lobe between male coxae 4 swollen, base stout, slightly attenuated near tip, knob-like when seen in lateral view, tip subtruncate.

LEGS (Fig. 39H–J): Long and slender. Male femora 5 and 6 moderately humped ventrally in middle portion.

GONOPODS (Figs 41, 42): Coxa (cx) longer than prefemur. Cannula (ca) long and slender. Prefemur (pfe) ca. 2/3 as long as femur. Femur (fe) long and slender. Mesal sulcus (ms) and lateral sulcus (ls) conspicuous, very deep. Postfemur (pof) conspicuous, ventrally narrow and short. Solenophore (sph) well-developed: lamina lateralis (ll) well-developed, inner surface subsided, anterolaterally with an inconspicuous furrow; with conspicuous ventral ridge (vrl): lamina medialis (lm) well-developed; process (plm) long, tip blunt, directed mesad; distal lobe (dlm) distally with two distinct lamellae (equal in size); broad lobe (blm) dorsally thick at the edge, with a wide and conspicuous indentation between broad lobe (blm) and distal lobe (dlm). Solenomere (sl) very long.

Known only from east Thailand (Chantaburi, Chonburi, Sa Kaeo and Rayong Provinces). Interestingly, this species exists in both limestone areas and granitic mountains. It was seen crawling on rocks during the rainy season and occurs only in natural habitat inside primary forest. On the basis of current data, the distribution area is quite narrow, and the species seems to be restricted to the eastern part of Thailand. We thus regard D. euros sp. n. to be an endemic for the Thai fauna.

The observation of all living specimens reveals variation on colour of paraterga within a population; yellow in some specimens, yellowish orange to orange in others.

Desmoxytes euros sp. n. strongly resembles D. planata in several morphological characters (except for the characters mentioned in the diagnosis); notably the gonopod characters are identical. However, our initial study on DNA barcoding gene (COI) revealed that D. planata and the new species are separated enough to support the suggestion that D. planata and the new species are indeed different species (paper in preparation).

Because of the similarity in gonopod morphology, it is difficult to discriminate old material of D. planata and D. euros sp. n. However, they can be distinguished by colour of paraterga (yellow or yellow orange in D. euros sp. n., pink in D. planata), and by characters of hypoproct (subtriangular in D. euros sp. n., subtrapeziform in D. planata).

We kept several adults in an acrylic box with litter at room temperature. Two weeks later, we found a nest with eggs and a cluster of stadium 1 juveniles at ca. 2 cm depth in the soil and leaf litter (Fig. 37E, F).

None known.

Male (CUMZ), THAILAND, Trang Province, Palian District, Tham Khao Ting, 7°09'31"N, 99°48'10"E, ca. 42 m a.s.l., 8 July 2017, leg. C. Sutcharit, R. Srisonchai and ASRU members.

13 males, 4 females (CUMZ), 1 male, 1 female (ZMUC), 1 male (ZMUM), 1 male (NHMW), 1 male (NHMUK), same data as holotype. 3 males, 3 females, 2 juveniles (CUMZ), THAILAND, Trang Province, Palian District, Tham Khao Ting, 7°09'31"N, 99°48'10"E, ca. 42 m a.s.l., 31 August 2015, leg. C. Sutcharit, R. Srisonchai and ASRU members.

7 males, 3 females (CUMZ), THAILAND, Satun Province, Thung Wa District, Tham Khan Ti Phol, 7°05'08"N, 99°47'54"E, ca. 80 m a.s.l., 8 July 2017, leg. C. Sutcharit, R. Srisonchai and ASRU members.

Collum with one row of 3+3 setae (anterior row); paraterga wing-like (not knife-shaped); metaterga 2–19 with 2+2 tubercles in anterior row and 2+2 tubercles in posterior row; male femora 5 and 6 modified; lamina lateralis (ll) distally rough, anterolaterally with 2–3 distinct furrows; process (plm) of lamina medialis very short. Similar in these respects to D. perakensis sp. n. Differs from that species by having body black or brownish black contrasting with yellowish brown paraterga; paraterga narrower; process (plm) of lamina medialis indistinctly demarcated from distal lobe (dlm); distal lobe (dlm) of lamina medialis with one lamella.

The name is a Latin noun, referring to the shape of process (plm) and the distal lobe (dlm) on lamina medialis which somewhat resemble a handheld fan or flyswatter.

SIZE: Length 32–35 mm (male), 34–36 mm (female); width of midbody metazona ca. 2.2 mm (male), 2.5 mm (female). Width of head < collum = body ring 2 = 3 = 4 < 5–16, thereafter body gradually tapering toward telson.

COLOUR (Fig. 43A–C): In life with body brownish black or black; metaterga and antenna black (except distal part of antennomere 7 and antennomere 8 whitish); surface below paraterga, head and epiproct brownish black; paraterga yellowish brown; sterna and legs brown; a few basal podomeres brownish white.

ANTENNAE (Fig. 44D): Moderately long and slender, reaching to body ring 6 (male) and 4–5 (female).

COLLUM (Fig. 44A): With 1 transverse anterior row of 3+3 setae; paraterga of collum low, elevated at ca. 10°–15°, directed caudolaterad, with 2 distinct notches on lateral margin.

TEGUMENT: Moderately shining; collum and metaterga coarsely microgranulate; prozona finely shagreened; surface below paraterga coarsely microgranulate; sterna and epiproct smooth.

METATERGA (Fig. 44A–C): With 2 transverse rows of conspicuous tubercles; metaterga 2–19 with 2+2 anterior and 2+2 posterior tubercles.

PARATERGA (Fig. 44E, F): Directed caudolaterad on body rings 2–17, elevated at ca. 45° (male) 45° (female); directed increasingly caudad on body rings 18 and 19; anterior margin with 2 distinct notches, on lateral margin of body rings 9, 10, 12, 13, 15–18 with tiny denticle near the tip.

TELSON (Fig. 45C–G): Epiproct: tip emarginate; lateral setiferous tubercles inconspicuous; apical tubercles conspicuous, small, knob-like. Hypoproct subtrapeziform, broad; caudal margin round, with two conspicuous setiferous tubercles.

STERNA (Fig. 46): Cross-impressions shallow. Sternal lobe between male coxae 4 swollen, suberect, subtrapeziform when seen in posterior view, tip usually truncate (in some specimens slightly round).

LEGS (Fig. 45H–J): Long and slender. Male femora 5 and 6 strongly humped ventrally in middle portion.

GONOPODS (Figs 47, 48): Coxa (cx) subequal in length to prefemur. Cannula (ca) quite long and slender. Telopodite quite stout. Prefemur (pfe) ca. 2/3 as long as femur. Femur (fe) somewhat stout, slightly enlarged distally. Mesal sulcus (ms) and lateral sulcus (ls) conspicuous, very deep. Postfemur (pof) conspicuous, ventrally narrow and short. Solenophore (sph) well-developed: lamina lateralis (ll) rough, anterolaterally with 2–3 distinct furrows, deep; ventral ridges (vrl) conspicuous: lamina medialis (lm) well-developed; process (plm) very short, indistinctly demarcated from distal lobe; distal lobe (dlm) distally with one lamella; broad lobe (blm) thick, clearly demarcated from distal lobe (dlm) by a narrow and deep indentation. Solenomere (sl) long, apically twisted.

Known only from the type locality and a few nearby localities. The new species is restricted to limestone habitats (Fig. 43D), and it is sympatric with D. delfae at Tham Khao Ting and Tham Khan Ti Phol. Unlike the bright orange D. delfae, which was easily spotted crawling on branches of shrubs and on rocks, the new species, blackish brown, was found on rocks where it was quite hard to see. This suggests that these two species, although sharing the same habitat, may show microhabitat differences, but this has not yet been studied in detail. We assume that the new species is distributed along limestone mountain ranges in a narrow area at the border between Trang and Satun Provinces. This species should be regarded as endemic to the Thai fauna.

Desmoxytes delfae co-occurs at the same localities.

Male (CUMZ), THAILAND, Kanchanaburi Province, Thong Pha Phum District, Prang Ka Sri Temple, 14°39'05"N, 98°40'08"E, ca. 107 m a.s.l., 15 August 2016, leg. C. Sutcharit, R. Srisonchai and ASRU members.

19 males (CUMZ), 2 males (ZMUC), 1 male (ZMUM), 1 male (NHMW), 1 male (NHMUK), same data as holotype.

, all from THAILAND, Kanchanaburi Province, Thong Pha Phum District: 4 males (CUMZ), Tham Khao Noi Bureau of Monks (Wat Tham Khao Noi), 14°41'55"N, 98°31'33"E, ca. 225 m a.s.l., 21 August 2015, leg. E. Jeratthitikul and R. Srisonchai. 3 males, 1 female (CUMZ), Tham Khao Noi Bureau of Monks (Wat Tham Khao Noi), 14°41'55"N, 98°31'33"E, ca. 225 m a.s.l., 15 August 2016, leg. C. Sutcharit, R. Srisonchai and ASRU members. 6 males, 1 female (CUMZ), Wat Huay Charoen Srattha Tham, 14°39'27"N, 98°31'38"E, ca. 202 m a.s.l., 11 October 2015, leg. C. Sutcharit and R. Srisonchai. 1 female (CUMZ), Huay Kayeng Subdistrict, Tham Pong Chang Monastery, 14°44'38"N, 98°30'26"E, ca. 209 m a.s.l., 11 October 2015, leg. C. Sutcharit and R. Srisonchai. 3 males, 5 females (CUMZ), Wat Pak Lam Philok, 14°37'39"N, 98°34'27"E, ca. 280 m a.s.l., 11 October 2015, leg. C. Sutcharit and R. Srisonchai. 4 males, 1 female (CUMZ), Prang Ka Sri temple, 14°39'05"N, 98°40'08"E, ca. 107 m a.s.l., 24 July 2016, leg. P. Pimvichai and P. Prasankok.

Sai Yok District: 2 males, 2 females (CUMZ), Daowadueng Cave, 14°28'23"N, 98°50'04"E, ca. 132 m a.s.l., 15 August 2016, leg. C. Sutcharit, R. Srisonchai, and ASRU members.

Metaterga 2–8 with 2+2 tubercles/cones/spines in anterior row and 2+2 tubercles/cones/spines in posterior row; metaterga 9–19 with 3+3 tubercles/cones/spines in posterior row. Similar in these respects to D. breviverpa, D. purpurosea, D. takensis, and D. taurina. Differs from those by having: metaterga 9–19 with two rows of 3(2)+3(2) tubercles/cones/spines in anterior row; lamina lateralis (ll) round and compact; tip of process (plm) of lamina medialis terminating in a sharp spine; distal lobe (dlm) of lamina medialis long; broad lobe (blm) dorsally expanded.

The name honours Sergei I. Golovatch, a myriapodologist at the Institute for Problems of Ecology and Evolution, Russian Academy of Sciences, who has enthusiastically encouraged millipede research in Thailand, in recognition of his extensive work on the taxonomy of millipedes – especially in family Paradoxosomatidae.

SIZE: Length 27–31 mm (male), 32 mm (female); width of midbody metazona ca. 1.9 mm (male), 2.3 mm (female). Width of head < collum < body ring 2 = 3 = 4 < 5–16, thereafter body gradually tapering towards telson.

COLOUR (Fig. 49A–C): In life with body vivid pink; paraterga, metaterga, surface below paraterga and epiproct pink; head brown; antenna black, except distal part of antennomere 7 and antennomere 8 whitish; sterna and legs pinkish brown; a few basal podomeres brown to whitish.

ANTENNAE (Fig. 50D): Very long and slender, reaching to body ring 7 (male) and 5 (female) when stretched dorsally.

COLLUM (Fig. 50A): With 3 transverse rows of setae and setiferous tubercles, 4+4 anterior setae, 1+1 intermediate setae and 2+2 posterior tubercles (lateral seta in anterior row located almost at base of paraterga in some specimens; lateral tubercles in posterior row located almost halfway to intermediate row); paraterga of collum low, elevated at ca. 15°–20°, directed caudolaterad, with one conspicuous notch on lateral margin.

TEGUMENT: Slightly shining; collum and metaterga microgranulate; prozona finely shagreened; surface below paraterga finely microgranulate; sterna and epiproct relatively smooth.

METATERGA (Fig. 50A–C): With 2 transverse rows of setiferous tubercles, cones and spines; metaterga 2–8 with 2+2 anterior cones and 2(3)+2(3) posterior spines; metaterga 9–17 with 3(2)+3(2) anterior cones and 3(4)+3(4) posterior spines; metatergum 18 with with 3+3 anterior cones and 3+3 posterior cones; metatergum 19 with with 3+3 anterior tubercles and 3+3 posterior tubercles.

PARATERGA (Fig. 50E, F): Directed caudolaterad on body rings 2–17, elevated at ca. 45° (male) 40° (female); directed increasingly caudad on body rings 18 and 19; anterior margin with 2 distinct notches, on lateral margin of body rings 9, 10, 12, 13, 15–18 with tiny denticle near the tip.

TELSON (Fig. 51C–G): Tip subtruncate; lateral setiferous tubercles inconspicuous, apical tubercles small and inconspicuous. Hypoproct subtrapeziform; caudal margin round, with small inconspicuous setiferous tubercles.

STERNA (Fig. 52): Cross-impressions shallow. Sternal lobe between male coxae 4 subtrapeziform; base slightly enlarged; tip emarginate; swollen near pores.

LEGS (Fig. 51H–J): Long and slender. Male femora 5 and 6 strongly humped ventrally in middle portion.

GONOPODS (Figs 53, 54): Coxa (cx) longer than prefemur. Cannula (ca) slender. Prefemur (pfe) ca. 2/3 as long as femur. Femur (fe) long, slightly curved. Mesal sulcus (ms) and lateral sulcus (ls) conspicuous, deep. Postfemur (pof) conspicuous, ventrally wide. Solenophore (sph) well-developed: lamina lateralis (ll) round and compact (obvious when seen in ventral view): lamina medialis (lm) well-developed; process (plm) somewhat short, tip terminating in a sharp spine (in some specimens with a tiny spine-like process situated between process (plm) and distal lobe (dlm)); distal lobe (dlm) quite long, distally with two indistinctly separated lamellae; broad lobe (blm) dorsally expanded, indentation between broad lobe (blm) and distal love (dlm) very wide and shallow. Solenomere (sl) relatively long.

Known from the type locality and nearby areas in Kanchanaburi Province only. The type locality is situated on a small, isolated limestone mountain near Khwae Noi River. All specimens were found in limestone habitats (Fig. 49D).

This species is distributed along the limestone mountain ranges in Sai Yok and Thong Pha Phum districts. Based on many intensive surveys, the current distribution of the new species is evidently quite narrow, ca. 100 km². Thus, D. golovatchi sp. n. should be regarded as a Thai endemic.

Desmoxytes golovatchi sp. n. is aposematic in its vivid pink body. During the field trips, this animal was noticeable by the contrast of its bright colour to green leaves or brown rocks, it thus was easy to see and collect after rain.

This species is morphologically similar to D. breviverpa, D. purpurosea, D. takensis, and D. waepyanensis sp. n. with which it shares colourful pink or red body colour, as well as further characters, viz., the same patterns of row of cones on metaterga (metaterga 2–8 with 2+2 cones in anterior row).

The new species was found in one place together with D. octoconigera sp. n. (see detail in D. octoconigera sp. n.), with D. planata at Wat Huay Charoen Srattha Tham and Tham Khao Noi Bureau of Monks, and with D. purpurosea at Daowadueng Cave. This species and D. purpurosea were hand-collected after rain when lots of them were climbing on vegetation and limestone rocks. Microhabitat differences have not yet been observed. Moreover, D. planata also occurs near the new species, but the habitats of these two species are clearly different: D. planata was found on humid cement and on construction materials whereas D. golovatchi sp. n. was seen crawling on limestone rock.

Male (CUMZ), THAILAND, Kanchanaburi Province, Sangkhla Buri District, Wat Tham Kaeo Sawan Bandal, 15°18'18"N, 98°24'57"E, ca. 334 m a.s.l., 16 August 2016, leg. C. Sutcharit, R. Srisonchai and ASRU members.

22 males, 11 females (CUMZ), 2 males (ZMUC), same data as holotype; 1 female; 1 broken female (CUMZ), same locality as holotype, 10 July 2009, leg. S. Panha and ASRU members.

, all from THAILAND, Kanchanaburi Province, Sangkhla Buri District: 3 broken males, 1 female, 2 broken and mixed specimens, 2 broken and mixed females? (CUMZ), Kra Teng Cheng Waterfall, 15°01'30"N, 98°36'05"E, ca. 208 m a.s.l., 10 July 2009, leg. C. Sutcharit, R. Srisonchai and ASRU members. 1 broken male missing gonopods, 5 males, 2 females (CUMZ), Kroeng Krawia Waterfall, 14°58'53"N, 98°37'54"E, ca. 255 m a.s.l., 10 July 2009, leg. S. Panha and ASRU members. 2 males, 3 juveniles (CUMZ), Takhian Thong Waterfall, 15°17'58"N, 98°26'56"E, ca. 241 m a.s.l., 10 July 2009, leg. S. Panha and ASRU members. 1 broken male (CUMZ), mountain near the Three Pagodas Pass, 15°18'20"N, 98°24'01"E, ca. 368 m a.s.l., 19 December 2010, leg. S. Panha and ASRU members. 3 males (CUMZ), Kra Teng Cheng Waterfall, 15°01'30"N, 98°36'05"E, ca. 208 m a.s.l., 16 August 2016, leg. C. Sutcharit, R. Srisonchai and ASRU members. 2 males, 2 females (CUMZ), near Ban Songkaria (Songkaria Village), limestone mountain, 15°13'01"N, 98°27'06"E, ca. 206 m a.s.l., 16 August 2016, leg. C. Sutcharit, R. Srisonchai and ASRU members. 7 males (CUMZ), Wat Tham Sukhlo, 15°02'14"N, 98°34'59"E, ca. 196 m a.s.l., 16 August 2016, leg. C. Sutcharit, R. Srisonchai and ASRU members.

Thong Pha Phum District: 4 males (CUMZ), Kroeng Krawia Checkpoint, 14°56'32"N, 98°40'11"E, ca. 347 m a.s.l., 16 August 2016, leg. C. Sutcharit, R. Srisonchai and ASRU members. 2 males, 1 female (CUMZ), Tham Khao Noi Bureau of Monks (Wat Tham Khao Noi), 14°41'55"N, 98°31'33"E, ca. 225 m a.s.l., 21 August 2015, leg. E. Jeratthitikul and R. Srisonchai. 2 males (CUMZ), Tham Khao Noi Bureau of Monks (Wat Tham Khao Noi), 14°41'55"N, 98°31'33"E, ca. 225 m a.s.l., 15 August 2016, leg. C. Sutcharit, R. Srisonchai and ASRU members.

Differs from all other Desmoxytes species by the combination of the following characters; collum with three rows of 5+5 anterior, 1(2)+1(2) intermediate, and 3+3 posterior setiferous tubercles; metaterga 2–8 with two rows of 3+3 (anterior row) and 3+3 (posterior row) setiferous cones; metaterga 9–17 with two rows of 4(3)+4(3) (anterior row) and 4(5)+4(5) (posterior row) setiferous cones; sternal cone between male coxae 4 incompletely bilobed, cordiform; lateral lamella of distal lobe (dlm) on lamina medialis broad and thin, demarcated from broad lobe (blm) by a deep indentation.

The name is a Latin adjective, referring to the two rows each with eight setiferous cones on metaterga 9–17.

SIZE: Length 24–30 mm (male), 30–32 mm (female); width of midbody metazona ca. 1.75 mm (male), 2.0 mm (female). Width of head > collum = body ring 2 = 3 = 4 < 5–16, thereafter body gradually tapering toward telson.

COLOUR (Fig. 55A–C): In life with body dark brown (male), brown (female); paraterga and sterna brown to whitish; metaterga, surface below paraterga and antenna dark brown (except antennomeres 6–8 whitish); head and epiproct brown; a few basal podomeres brown to whitish.

ANTENNAE (Fig. 56D): Very long and slender, reaching to body ring 7–8 (male) and 6 (female) when stretched dorsally.

COLLUM (Fig. 56A): With 3 transverse rows of setiferous tubercles, 5+5 anterior, 1(2)+1(2) intermediate and 3+3 posterior tubercles (lateral tubercles of anterior row located almost at base of paraterga in some specimens); paraterga of collum low, elevated at ca. 20°, directed caudad, with one distinct notch on lateral margin.

TEGUMENT: Quite dull, slightly shining; collum and metaterga coarsely microgranulate; prozona finely shagreened; surface below paraterga finely microgranulate; sterna and epiproct smooth.

METATERGA (Fig. 56A–C): With 2 transverse rows of setae, setiferous tubercles and setiferous cones; metaterga 2–8 with 3+3 anterior and 3+3 posterior cones; metaterga 9–17 with 4(3)+4(3) anterior and 4(5)+4(5) posterior cones; metatergum 18 with 4+4 anterior and 4+4 posterior tubercles; metatergum 19 with 4+4 anterior and 4+4 posterior setae.

PARATERGA (Fig. 56E, F): Directed caudolaterad on body rings 2–17, elevated at ca. 50° (male) 45° (female); directed increasingly caudad on body rings 18 and 19; anterior margin with 2 distinct notches, on lateral margin of body rings 9, 10, 12, 13, 15–18 with tiny denticle near the tip.

TELSON (Fig. 57C–G): Epiproct: tip subemarginate; lateral setiferous tubercles small but conspicuous; apical tubercles conspicuous. Hypoproct subtrapeziform; caudal margin round, with inconspicuous setiferous tubercles.

STERNA (Fig. 58): Cross-impressions shallow. Sternal lobe between male coxae 4 swollen, tip emarginate to incompletely bilobed, cordiform when seen in ventral view.

LEGS (Fig. 57H–J): Very long and slender. Male femora 5 and 6 swollen in middle part.

GONOPODS (Figs 59, 60): Coxa (cx) longer than prefemur. Cannula (cx) slender. Prefemur (pfe) ca. 2/3 as long as femur. Femur (fe) long and slender. Mesal sulcus (ms) and lateral sulcus (ls) very deep and wide. Postfemur (pof) conspicuous, ventrally wide. Solenophore (sph) well-developed: lamina lateralis (ll) swollen, lobe-like when seen in ventral view, conspicuous: lamina medialis (lm) well-developed; process (plm) long, directed mesoanteriad, tip almost blunt (in some specimens tip bifurcating into two sharp small spines); distal lobe (dlm) well-developed, distally with two lamellae (lateral lamella broad and thin, projecting laterad, in situ terminating close to tip of solenomere (sl); mesal lamella shorter than lateral one, apical margin serrate); broad lobe (blm) thick, distinctly demarcated from distal lobe (dlm) by a very deep and narrow indentation. Solenomere (sl) quite long.

D. octoconigera sp. n. is known only from Kanchanaburi Province. At the type locality where the holotype and the majority of the paratypes were collected, the animals were crawling on litter inside rock holes; some specimens were seen crawling on rock walls near the cave.

Interestingly, some specimens of D. planata were also found near the cave, however, according to our surveys this species is usually found in places with human activity. We assume that it was probably accidentally introduced to the cave by human actions. Therefore, D. planata and the new species might not share microhabitat, although they live syntopically.

The new species and D. golovatchi sp. n. are sympatric in one location at Tham Khao Noi Bureau of Monks (Wat Tham Khao Noi), and they both have narrow distribution ranges (<100 km²). Currently, the type locality of D. octoconigera sp. n. is situated in an area with considerable human activity (Bureau of Monks and tourist cave), where the forest habitat is cut every year.

We have tried in vain to find this species in another area nearby. Given the narrow distribution range, the new species is probably endemic to Thailand.

There is considerable variation in tip of process (plm) of lamina medialis within populations. The process tip in some specimens is bifurcate as two small spines whereas in other specimens it may be relatively blunt.

Desmoxytes golovatchi sp. n. and D. planata.

Male (CUMZ), MALAYSIA, Perak, Ipoh, Ulu Kinta, near The Lost World Tambun Theme Park, limestone mountain, 4°37'45"N, 101°09'21"E, ca. 73 m a.s.l., 27 September 2007, leg. B. W. Ng, S. Panha and ASRU members.

4 males (CUMZ), same data as holotype.

Differing from all other species, except D. delfae and D. aurata sp. n., by having a low degree of elevation of paraterga, femora 5 and 6 strongly humped ventrally in middle part, collum with a row of 3+3 anterior setae and metaterga 2–18 with rows of 2+2 anterior and 2+2 posterior small tubercles. Differs from D. delfae and D. aurata sp. n. by having paraterga wider than those species; lamina lateralis (ll) with two distinct furrows ventrolaterally; process (plm) of lamina medialis lamellar, tip blunt.

The name is a Latin adjective referring to the type locality.

SIZE: Length 24–26 mm (male), 27–29 mm (female); width of midbody metazona ca. 1.9 mm (male), 2.2 mm (female). Width of head < collum < body ring 2 = 3 < 4 < 5–16, thereafter body gradually tapering towards telson.

COLOUR: In life with bright orange. Colour in alcohol: after 10 years in alcohol pale yellow to whitish.

ANTENNAE (Fig. 61D): Moderately long and slender, reaching to body ring 6 (male) and 5 (female) when stretched dorsally.

COLLUM (Fig. 61A): With 1 transverse anterior row of 3+3 setae; paraterga of collum low, almost horizontal, directed caudolaterad, with two inconspicuous setiferous notches on lateral margin.

TEGUMENT: Slightly shining and smooth; collum, metaterga, sterna and epiproct smooth; prozona finely shagreened; surface below paraterga finely microgranulate.

METATERGA (Fig. 61A–C): With 2 transverse rows of small, inconspicuous setae and tubercles; metaterga 2–18 with 2+2 anterior and 2+2 posterior tubercles; metatergum 19 with 2+2 anterior and 2+2 posterior setae.

PARATERGA (Fig. 61E, F): Directed caudolaterad on body rings 2–17, elevated at ca. 25°–30° (male) 25° (female); directed increasingly caudad on body rings 18 and 19; anterior margin with 2 distinct notches, on lateral margin of body rings 9, 10, 12, 13, 15–18 with tiny denticle near the tip.

TELSON (Fig. 62C–G): Epiproct: tip truncate; lateral setiferous tubercles and apical tubercles inconspicuous. Hypoproct subtriangular; caudal margin round, with very small and inconspicuous setiferous tubercles.

STERNA (Fig. 63): Cross-impressions shallow. Sternal lobe between male coxae 4 subtrapeziform, tip subtruncate, base slightly enlarged.

LEGS (Fig. 62H–J): Long and slender. Male femora 5 and 6 strongly humped ventrally in middle portion.

GONOPODS (Figs 64, 65): Coxa (cx) longer than prefemur. Cannula (ca) somewhat stout. Prefemur (pfe) ca. 2/3 as long as femur. Femur (fe) quite long and slender. Mesal sulcus (ms) and lateral sulcus (ls) conspicuous, very deep. Postfemur (pof) conspicuous, ventrally narrow and short. Solenophore (sph) well-developed: lamina lateralis (ll) swollen, quite thin, anterolaterally with two distinct furrows, dorsolaterally subsided, ventral ridge (vrl) conspicuous: lamina medialis (lm) well-developed; process (plm) short, lamellar, tip blunt; distal lobe (dlm) distally with two lamellae (mesal lamella smaller than lateral one); broad lobe (blm) dorsally somewhat thick, demarcated from distal lobe (dlm) by conspicuous indentation. Solenomere (sl) long.