Helicodesmus anichkini, Golovatch, Sergei I., Geoffroy, Jean-Jacques & VandenSpiegel, Didier, 2014

Golovatch, Sergei I., Geoffroy, Jean-Jacques & VandenSpiegel, Didier, 2014, Review of the millipede family Trichopolydesmidae in the Oriental realm (Diplopoda, Polydesmida), with descriptions of new genera and species, ZooKeys 414, pp. 19-65 : 52-55

Helicodesmus anichkini sp. n. Figs 13-15

Type material.

Holotype ♂ (MNHN JC 360), Vietnam, Dongnai Prov., Cat Tien National Park, 107°10'-107°34'E, 11°21'-11°48'N, lowland tropical forest, litter and topsoil, 01.06.2005, leg. A. Anichkin.

Paratypes: 2 ♂, 1 ♀ (ZMUM ρ 2340, ρ 2343), 1 ♂ (SEM), same locality, together with holotype; 1 ♂ (ZMUM ρ 2342), same locality, 01.04.2005; 2 ♂ (MNHN JC 360), 1 ♂ (ZMUM ρ 2341), same locality, 15.07.2005; 1 ♂, 1 ♀ (MNHN JC 360), 2 ♂ (ZMUM ρ 2344, ρ 2345), same locality, 23.11.2005; 1 ♂ (MNHN JC 360), same locality, 17.07.2005; 1 ♂ (ZMUC), same locality, 15.05.2005, all leg. A. Anichkin.

Name.

To honour Alexander E. Anichkin, who provided for study all millipede material he had collected in Cat Tien National Park, including three trichopolydesmids described here.

Description.

Length of adults ca 3.0-4.0 mm, width of midbody pro- and metazonae 0.28-0.32 and 0.4-0.45 mm (♂, ♀). Coloration in alcohol uniformly pallid, tegument often nearly translucent.

Body with 19 segments (♂, ♀). Tegument dull, texture of nearly entire body delicately alveolate to scaly, only sterna nearly smooth (Fig. 13 A–I). Head very densely and finely pilose; epicranial suture highly superficial; genae squarish (Fig. 13A, D, G, K); gnathochilarium rather broad, sparsely and uniformly setose (Fig. 13K); isthmus between antennae about 1.2-1.3 times as broad as diameter of antennal socket (Fig. 13G, K). Antennae short (Fig. 13A, D, G), reaching only behind collum when stretched dorsally, not geniculate, rather strongly clavate due to a particularly enlarged antennomere 6, the latter with a usual, tight, distodorsal group of numerous, bacilliform sensilla; a similar, but smaller, also distodorsal group of sensilla on antennomere 5; antennomere 7 with a smaller distodorsal group of only a few shorter and curved sensilla in front of a tiny mid-dorsal knob.

In width, collum = segment 3 = 4 <5 <2 <6-15 <head; body gradually tapering on segments 16-18 (Fig. 13 D–F). Paraterga mostly moderately wide, starting from collum, set rather low (at about upper 1/3 of body height, Fig. 13J), at most small ridges with 2-3 lateral, setigerous knobs, absent from segment 18, caudal corner never produced behind rear tergal margin even in poriferous segments (Fig. 13 A–G, M). Ozopores evident, ovoid, dorsolateral, mostly lying closer to lateral edge (Fig. 13M). Collum biconvex, sides (= paraterga) narrowly rounded, dorsal surface with 3 transverse rows of 5+5, 3+3 and 4+4 rather long setae dorsally and 2 similar setae on paraterga (Fig. 13A, D). Each following metatergum with 3+3 or, more rarely, 4+4, similarly long, bacilliform, delicately ribbed setae arranged in 3 transverse regular rows and borne on knobs; sulci between the rows absent (Fig. 13 A–G, L, M). Stricture between pro- and metazonae rather deep and narrow, microalveolate like adjacent metazonae (Fig. 13E, L). Limbus very fine, delicately and densely microcrenulate (Fig. 13L, M). Pleurosternal carinae absent (Fig. 13 A–C). Epiproct short, conical, truncate, directed caudoventrally; pre-apical papillae evident (Fig. 13C, F, I). Hypoproct subtrapeziform, caudal setigerous papillae moderate and well separated (Fig. 13I).

Sterna without modifications, rather broad and sparsely setose (Fig. 13G, H). Legs short and stout, ca 1.1-1.2 (♂) or 0.9-1.0 (♀) times as long as midbody height; prefemora, femora, postfemora and tibiae clearly incrassate, especially so in ♂ (Fig. 13N), tarsi longest, slender, sphaerotrichomes missing; claws simple, slightly curved; ♂ coxae 2 with very short, membranous, cylindrical gonapophyses (Fig. 13G).

Gonopod aperture transversely oblong-oval, taking up most of ventral part of metazonite 7 (Fig. 14A). Gonopod coxae rather small (gonocoel not deep), sparsely setose and clearly micropapillate laterally (Figs 14, 15); telopodites quite well exposed and unusually transverse, but stout and remarkably complex, very strongly twisted, partly fimbriate(curved ventral projections c1 and c2) or plumose (a long lateral process k), with several outgrowths of varying shapes (a stump-shaped, rounded, mesal i and 2 indistinctly separated, densely microdentate, also rounded m and l); prefemoral part about half the height of telopodite, demarcated on lateral (not medial!) side by an oblique seminal groove running further mesad onto a medioventral outgrowth of acropodite to terminate distally at joint base of c1 and c2, with neither a solenomere nor an accessory seminal chamber, nor a pulvillus.