Desmoxytes des Srisonchai, Enghoff & Panha

Srisonchai, Ruttapon, Enghoff, Henrik, Likhitrakarn, Natdanai & Panha, Somsak, 2016, Four colorful new species of dragon millipedes, genus Desmoxytes Chamberlin, 1923, from northern Thailand (Diplopoda: Polydesmida: Paradoxosomatidae), Zootaxa 4170 (1), pp. 93-113 : 94-99

Desmoxytes des Srisonchai, Enghoff & Panha sp. n.

( Figs. 1 A, 1B, 2–4)

Holotype: male ( CUMZ) THAILAND, Chiang Mai Province, Fang District, Doi Angkhang, near Royal Agricultural Station , 19º54'26"N, 99°2.0'26"E, ca 1,425 m a.s.l., 12 August 2014, leg. N. Likhitrakarn.

Paratypes: 2 males, 2 females ( CUMZ) same data with holotype ; 1 male, 2 females ( CUMZ), THAILAND, Chiang Mai Province, Chiang Dao District, Wat Tham Krab , 19º33'31.92"N, 99°3.0'46.91"E, ca 620 m a.s.l., 25 October 2015, leg. C. Sutcharit, R. Srisonchai, T. Seesamut and A. Pholyotha.

Etymology. The species epithet is a noun in apposition and refers to the shape of the paraterga which reminds us of an ancient Egyptian flint knife (des).

Diagnosis. Metaterga with 2 transverse rows of setae, 2+2 setae in anterior row, 2+ 2 in posterior one; shocking pink paraterga contrasting with a dark brown general body color. D. des sp. n. shares these characters with D. planata , but differs from that species in having wing-shaped, knifelike paraterga, having the lateral sulcus between femorite and postfemorite poorly developed, having a prominent sulcus separating two ridges dorsally on lamina lateralis (ll), having a dentiform lamella on lamina medialis (lm), having male femora 5 and 6 very strongly inflated and stout, and in having the hypoproct with a concave caudal margin.

Description. Length 26–34 mm (male), 30–34 mm (female), width of midbody prozona and metazona ca 1.8 and 2.5 mm (male), ca 2.2 and 3.0 mm (female).

Live coloration of body dark brownish; paraterga bright pink; surface below paraterga, head and metaterga dark brown; legs, antenna, epiproct and sterna brown; a few basal podomeres brownish pink ( Figs. 1 A, 1B, 2). Coloration in alcohol after twelve months faded to dark brown; metaterga and surface below paraterga dark brownish; paraterga, head, antenna, legs, sterna and epiproct brown.

Width of head <collum <segment 2 = 3 <4 = 5 <6–16, thereafter body gradually tapering towards telson. Head width 2.0– 2.2 mm (male), 2.0– 2.5 mm (female). Clypeolabral region sparsely setose, vertex bare; labrum and genae sparsely setose; epicranial suture distinct, shallow ( Figs. 4 A, 4D). Antennae quite long, surpassing segment 3 when stretched backward dorsally (both sexes) ( Fig. 4 D).

Collum ca 4.0 mm wide (both sexes), surface smooth and dull, with two transverse rows of inconspicuous setae; 3+3 anterior and 1+1 posterior setae; anterior margin subtruncate, posterior margin quite convex; paraterga strongly developed, wing-shaped, directed dorsolaterad at about 30º; with an inconspicuous notch on anterior margin ( Fig. 4 A).

Post-collum segments with surface of prozona and metazona finely shagreened, quite dull; paraterga smooth; surface below paraterga coarsely microgranulate with distinct wrinkles; sterna smooth ( Figs. 2 A–H, 4G). Suture between prozona and metazona wide, quite deep ( Figs. 2 A–F, 4B, 4E, 4G). Metaterga with two transverse rows of setiferous tubercles; metaterga 2–18 with 2+2 anterior and 2+2 posterior tubercles, all tubercles subequal in size; distance between the two mesal tubercles of anterior rows larger than distance between the mesal and the lateral tubercles on each side; distance between the two mesal tubercles of posterior rows smaller than distance between the mesal and the lateral tubercles on each side; metatergum 19 with 2+2 anterior and 2+2 posterior inconspicuous setae. Transverse sulcus on metaterga quite deep on segments 4–17, poorly expressed on segments 3 and 18, entirely missing on segments 2 and 19 ( Figs. 2 A, 2C, 2F, 4A–C). Mid-dorsal line absent.

Paraterga strongly developed, very broad at base, wing-shaped, directed dorsolaterad at about ca 30º ( Fig. 4 F), tapering and curving backwards, ending in sharp point; shoulder present; anterior margin with two distinct denticles, on metaterga 9, 10, 12, 13, 15–18 with an additional tiny denticle close to the tip ( Fig. 4 H: arrow); calluses on anterior margin of pore-bearing segments distinct ( Figs. 2 C, 2E, 4H). Ozopore (op) visible from above, ovoid, located on anterior margin of paratergum ( Fig. 4 H). Pleurosternal carinae forming complete, tooth-like crests on segment 2, small incomplete ridges on segment 3, missing on remaining segments ( Fig. 2 B).

Epiproct conoid; tip truncate; apical papillae without tubercles; with 2 pairs of paramedian setae without supporting tubercles; lateral papillae with conspicuous tubercles lying close to the tip ( Figs. 4 J–L). Hypoproct subtrapeziform; caudal margin quite concave, with very small setiferous tubercles ( Fig. 4 I).

Sterna sparsely setose, cross-impression shallow; sternal process between male coxae 4 modified, sparsely setose, subquadrate, tip truncate, two sternal pores on sternal process visible from posterior view ( Figs. 2 G, 2H, 4M). Legs long and slender, 3–3.2 (male) or 3.1–3.2 times (female) as long as midbody height ( Fig. 4 P). Male femora 5 and 6 distinctly humped ventrally in middle part, femur 5 subequal in width and length to femur 6, delicately and sparsely setose, tarsal brush absent ( Figs. 2 I, 4N, 4O).

Gonopods ( Figs. 3 , 4 Q–T) long, distal parts strongly condensed. Coxa (cx) about half as long as telopodite, dorsally densely setose, cannula long and slender. Prefemorite (pfe) almost half as long as telopodite, subequal in length to femorite, densely setose. Femorite (fe) elongated, with a prominent deep sulcus on mesal side demarcating the border between femorite and postfemoral part ( Fig. 4 Q, arrow), lateral sulcus poorly developed, seminal groove running entirely on mesal surface. Solenophore (sph) well-developed; lamina lateralis (ll) apically with a sulcus separating two ridges, inner ridge large, outer one smaller ( Fig. 4 T, arrow); lamina medialis (lm) broadly expanded, distally curving mesad, with dentiform lamella ( Fig. 4 S, arrow). Solenomere (sl) quite long, flagelliform, directed straight, twisted distally.

Distribution and habitat. This species is known only from its type locality and another locality in Chiang Mai Province, the two localities lie approximately 50 km apart. The holotype was taken from the limestone hill near the Royal Agricultural Station, Angkhang during the rainy season. Additional specimens were also found in limestone habitats.

Remark. The color of living examples of the new species is clearly aposematic and remarkable for the contrast between dark brownish body and the pink paraterga.

Figures

FIGURE 1. Live photographs of the new species. A, B: Desmoxytes des sp. n. — A; male holotype, B; female. C, D: Desmoxytes breviverpa sp. n. — male paratype. E, F: Desmoxytes takensis sp. n. — E; male paratype, F; female. G, H: Desmoxytes pinnasquali sp. n. — G: male holotype, H: mating couple.

FIGURE 2. Desmoxytes des sp. n. (male holotype). A, B: anterior body parts—dorsal view (A) and lateral view (B). C: segments 10 and 11 (op = ozopore) — dorsal view. D, F, J: posterior body parts—lateral view (D), dorsal view (F) and ventral view (J). E: segments 10 – 12 (op = ozopore) — lateral view. G, H: sternal process between male coxae 4 — posterior view (G) and lateral view (H). I: legs 5 – 7 — posterior view.

FIGURE 3. Desmoxytes des sp. n. (male paratype), right gonopod. A: lateral view. B: mesal view. C: ventral view. D, F: subdorsal view. E: dorsal view.

FIGURE 4. Desmoxytes des sp. n. (male holotype). A: head and segments 1 – 3 — dorsal view. B: segments 8 – 10 (op = ozopore) — dorsal view. C: posteriormost segments and telson segments—dorsal view D: head and antenna—anterior view. E: segments 8 – 10 — lateral view. F: segment 10 — posterior view. G: paraterga and sculpture of segment 10 — lateral view. H: paraterga of segment 10 (arrow = tiny denticle) — lateral view. I: last segment and telson; showing epiproct and hypoproctventral view. J – L: epiproct; J: dorsal view, K: lateral view, L: ventral view. M: sternal process between male coxae 4 — posterior view. N: male leg 5. O: male leg 6. P: male right anterior leg of segment 10. Q – T: right gonopod; Q: mesal view (cx = coxa, ca = cannula, pfe = prefemorite, fe = femorite, sg = seminal groove, sph = solenophore, arrow = sulcus on mesal side), R: lateral view, S: ventral view (ll = lamina lateralis, lm = lamina medialis, sl = solenomere, arrow = dentiform lamella), T: dorsal view (arrow = sulcus separating two ridges).