Desmoxytes octoconigera Srisonchai, Enghoff & Panha

Srisonchai, Ruttapon, Enghoff, Henrik, Likhitrakarn, Natdanai & Panha, Somsak, 2018, A revision of dragon millipedes I: genus Desmoxytes Chamberlin, 1923, with the description of eight new species (Diplopoda, Polydesmida, Paradoxosomatidae), ZooKeys 761, pp. 1-177 : 1

Desmoxytes octoconigera Srisonchai, Enghoff & Panha sp. n. Figs 55, 56, 57, 58, 59, 60

Holotype.

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.

Paratypes.

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.

Further specimens, not paratypes

, 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.

Diagnosis.

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.

Etymology.

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

Description.

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. 55 A–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. 56 A–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. 57 C–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. 57 H–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.

Distribution and habitat.

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.

Remarks.

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.

Coexisting species.

Desmoxytes golovatchi sp. n. and D. planata .