Desmoxytes rhinoceros, Likhitrakarn, Natdanai, Golovatch, Sergei I. & Panha, Somsak, 2015

Likhitrakarn, Natdanai, Golovatch, Sergei I. & Panha, Somsak, 2015, Two new species of dragon millipedes, genus Desmoxytes Chamnerlin, 1923, from Laos (Diplopoda: Polydesmida: Paradoxosomatidae), with redescriptions of all four species of Attems from Vietnam, Zootaxa 3931 (4), pp. 483-504 : 486-488

Desmoxytes rhinoceros sp. n.

Figs 1 A, B & 2–4.

Holotype male ( CUMZ), Laos, Champasak Province, Paksong District, Tad Fane Waterfall, ca 970 m a.s.l., 15°11'03"N, 106°07'37"E, 20.07.2013, leg. C. Sutcharit.

Paratypes. 1 female ( CUMZ), same District, Tad Gneueng Waterfall, ca 980 m a.s.l., 15°10'52"N, 106°08'23"E, 20.07.2013, leg. W. Siriwut. 1 female ( CUMZ), same Province, Pakxe District, Pha Suam Waterfall, ca 190 m a.s.l., 15°16'36"N, 105°55'21"E, 20.07.2013, leg. C. Sutcharit. 1 female ( CUMZ), Sekong Province, Lamam District, Tad Faek Waterfall, ca 140 m a.s.l., 15°14'44.60"N, 106°45'0.20"E, 20.07.2013, leg. S. Panha. 2 male, 4 females ( CUMZ), 1 male, 1 female ( ZMUM p2475), same Province, Kafey District, Ban Teu, forest near road, ca 470 m a.s.l., 15°25'03"N, 106°36'06"E, 17.10.2013, leg. C. Sutcharit and W. Siriwut.

Name. To emphasize the large anterobasal spine on the paraterga having the shape of a rhinoceros horn; a noun in apposition.

Diagnosis. Paraterga antler-shaped, with a prominent anterior spine at base; midbody metaterga with 2+2 and 4(5)+4(5) very evident spines in two transverse rows, one anterior, the other posterior; coloration of live specimens dark red; gonopod structure as in D. cattienensis , from southern Vietnam ( Nguyen et al., 2006), but the new species differs in the solenophore being trifid terminally.

Description. Length 17–24 (male) or 20–25 mm (female), width of midbody pro- and metazonae 1.0–1.7 and 3.4–4.1 mm (male) or 1.9–2.5 and 3.8–5.0 mm (female), respectively.

Live coloration dark red ( Fig. 1 A & B); paraterga and epiproct carmine red, head and antennae dark brownish, legs brown; coloration of alcohol material after four months of preservation faded to whitish or coral pink; head and antennae brown to pale brown; venter and a few basal podomeres pale brown to whitish, legs growing infuscate (brown) distad ( Fig. 2 A–J).

Clypeolabral region and vertex sparsely setose, epicranial suture distinct. Antennae rather long ( Figs 1 A, B & 2B), extending behind body segment 5 (male) or 3 (female) when stretched dorsally. In width, head <collum <segment 2 <3 <4 <5 <6–16 (both sexes); thereafter body gently and gradually tapering. Collum with three transverse rows of setigerous spines: 3+3 anterior, 3+3 intermediate and 1+1 posterior, anterior row being much larger than both others; paraterga stout and spiniform, directed dorsolaterad, with two strong anterior spines near base and ca 3/4 as high as paraterga ( Fig. 2 A & B). Postcollum paraterga antler-shaped, especially well so in male, upturned, directed dorsolaterad, tip bent posteriad, with a prominent anterior spine at base and an evident spine at 3/4 extent of paraterga ( Fig. 2 A–D, F–H); paraterga 9, 10, 12 and 13 each with one small, additional, subapical spine increasingly strong in segments 15–19. Ozopores (Op) lateral, located near notch at base of basal spine ( Fig. 2 D). Tegument dull, prozonae finely shagreened, metazonae coarsely shagreened to microgranulate, surface below paraterga coarsely microgranulate, sterna delicately microgranulate ( Fig. 2 A–J). Metaterga with two transverse rows of setigerous spines, lateral spines of posterior rows being much longer than others ( Fig. 2 A, C & F): metaterga 2–6 with 2+2 anterior and 3+3 posterior spines; metaterga 7 and 8 with 2(1)+2(1) anterior and 3(4)+3(4) posterior spines; following metaterga with 2+2 anterior and 4(5)+4(5) posterior spines. Tergal setae short, mostly abraded. Axial line visible (female) or barely traceable (male). Transverse sulcus usually visible on segments 2–19 ( Fig. 2 A, C & F), wide, line-shaped, shallow, reaching bases of paraterga, a little better developed in female. Stricture between pro- and metazonae narrow, shallow, beaded at bottom down to base of paraterga ( Fig. 2 A, C & F). Pleurosternal carinae complete crests with a sharp caudal tooth only in segments 2 and 3 ( Fig. 2 B, D & G). Epiproct unusual ( Fig. 2 F, G & H), flattened dorsoventrally, with 4+4 setigerous spines near a subtruncate tip. Hypoproct nearly semi-circular, setigerous knobs at caudal edge evident and well-separated.

Sterna sparsely setose, without modifications; cross-impressions shallow; a paramedian pair of small, but evident, fully separated, setose cones between male coxae 4 ( Fig. 2 I & J). Legs extremely long and slender, slightly incrassate in male, midbody ones ca 2.1–2.3 (male) or 1.3–1.5 times (female) as long as body height; male coxae 2 clearly elongated distoventrally ( Fig. 2 E). Prefemora without modifications ( Fig. 4 K), male tarsal brushes absent.

Gonopods ( Figs 3 & 4 ) subfalcate. Coxite moderately long, slightly curved caudad, rather densely setose distodorsally. Prefemur densely setose, as long as femorite. Femorite stout, strongly enlarged distad, seminal groove running entirely on mesal face. Solenophore (= lamina medialis) well-developed, with three apical lobes, supporting a rather short flagelliform solenomere well separated at base from solenophore.

Remark. The coloration of this species is clearly aposematic.

Figures

FIGURE 1. Habitus, live coloration. A, B: Desmoxytes rhinoceros sp. n., male holotype. C, D: Desmoxytes rhinoparva sp. n., male holotype. Photographed not to scale.

FIGURE 2. Desmoxytes rhinoceros sp. n., male holotype. A, B: anterior part of body, dorsal and lateral views, respectively. C, D: segments 9 – 11, dorsal and lateral views, respectively. E: coxae 2, sublateral view. F – H: posterior part of body, dorsal, lateral and ventral views, respectively. I, J: sternal cones between coxae 4, subcaudal and sublateral views, respectively. K: leg of segment 10, lateral view.

FIGURE 3. Desmoxytes rhinoceros sp. n., male holotype. A, B: left gonopod, mesal and lateral views, respectively. Scale bar: 0.2 mm.

FIGURE 4. Desmoxytes rhinoceros sp. n., male holotype. A, B, E, F: left gonopod, lateral, mesal, subcaudal and suboral views, respectively. C, D: distal part of left gonopod, lateral and mesal views, respectively. Scale bar: 0.2 mm.