Hylekobolus griseus Wesener, 2009

Wesener, Thomas, Enghoff, Henrik & Sierwald, Petra, 2009, Review of the Spirobolida on Madagascar, with descriptions of twelve new genera, including three genera of ' fire millipedes' (Diplopoda), ZooKeys 19 (19), pp. 1-128 : 106-108

Hylekobolus griseus Wesener , sp. n.

urn:lsid:zoobank.org:act:7BCC2A1D-F354-4402-8E85-53BF01FCD0A7

Material examined: 24 ♂, 32 ♀, 37 imm. Holotype: 1 ♂ (40 mm long), FMMC W092 A, Vohimena Eastern Slope , Enato, rainforest, 24°53’0.25” S, 46°59’2.77” E, leg. T. Wesener et al., 27.V.2007 Paratypes: 5 ♂, 5 ♀, 6 imm., FMMC W092 A, same data as holotype ; 1 ♂, 1 ♀, ZMUC W092 A, same data as holotype ; 1 ♂, 1 ♀, ZMH W092 A, same data as holotype ; 1 ♂, 1 ♀, CAS W092 A, same data as holotype ; 1 ♂, 1 ♀ ZSM W092 A, same data as holotype .

Other material examined: 5 ♂, 6 ♀, 6 imm., W092A, same data as holotype, University Antananarivo ; 1 ♂, FMMC, Province Toliara, Sainte Luce, S 9, littoral forest on sand, 24°47’S, 47°10’E, leg. T. Wesener, 06.IV.2003 ; 2 ♂, 2 ♀, 6 imm., FMMC W029 , Sainte Luce , S9, littoral forest on sand, 12 m, 24°46.769’ S, 47°10.288’ E, leg. T. Wesener et al., 01.VI.2007 ; 1 ♂, 3 ♀, 6 imm., W029, same data as previous, University Antananarivo ; 2 ♂, 5 ♀, 2 imm. FMMC W038 , Mandena , littoral forest on sand, 34 m, 24°57.260’ S, 46°59.499’ E, leg. T. Wesener et al., 02.VI.2007 ; 2 ♂, 5 ♀, 3 imm., W038, same data as previous, University Antananarivo ; 1 ♂, 1 ♀, 4 imm., FMMC W044 B, Andohahela, Malio , rainforest, 24°55.810’ S, 46°46.343’ E, leg. T. Wesener et al., 30.V.2007 ; 1 ♀, 4 imm., W044B, same data as previous, University Antananarivo .

Differential diagnosis: H. griseus can only be confused with H. albicollaris sp. n., which shares the small body size and a wide and partly membranous apical process (x) on the posterior gonopods ( Fig. 57G ). Both species differ in colour pattern (compare Fig. 57A with Fig. 58A ) and also slightly in the gonopod structure.

Description. Measurements: males with 44–47 rings, 38–45 mm long, 3.5–3.9 mm wide. Females with 44–47 rings, 37–45 mm long, 3.8–4.65 mm wide.

Coloration: collum margins, posterior part of telson and posterior margin of body rings white ( Figs 53B , 57A, E ). Legs and antennae white ( Fig. 53B ). Anterior part of body rings, telson, head and collum dark grey ( Figs 53B , 57A, E ). Eyes with 36–40 ocelli ( Fig. 57C ).

Anterior gonopod sternite basally wide, apically elevated into a slender, triangular lobe with a well-rounded tip ( Fig. 57E ). Mesal process of coxite slender and protruding ( Fig. 57E ). Apical telopodite process large and well-rounded. Retrorse margin wide, not projecting above telopodite ( Fig. 57G ); margin basally of apical process wide, projecting ( Fig. 57G ).

Posterior gonopods telopodite bent 90° ( Fig. 57F ). Lateral margin without a projection (w, Fig. 57F ). Apical process (x) wide, swollen and membranous ( Fig. 57H ). A membranous lobe (y) absent ( Fig. 57F ). Projection of sperm canal (z) extraordinary long and slender, widely extending beyond apical process ( Fig. 57H ).

Distribution and ecology: H. griseus sp. n. is widely distributed in the southeastern part of the littoral rainforest, as well as on the eastern slopes of the Vohimena Mountains. It also occurs in Malio, located on the eastern slopes of the Anosy Mountains. The absence of H. griseus from the Ambatotsirongorongo Mountain, which lies in the middle of its range, is enigmatic ( Fig. 54 ). At Ambatotsirongorongo, as well as on the western slopes of the Vohimena Mountains and in the Andohahela Isaka-Ivondro corridor, H. griseus is replaced by H. albicollaris sp. n. All specimens were collected in dead wood, as well as in mould which assembled in the axis of Pandanus leaves.

Etymology: griseus , adjective, refers to the dark grey colour of this species.

Figures

Figure 53. Living specimens of A Hylekobolus brachiosauroides sp. n., male B H. griseus sp. n., mating pair C H. albicollaris sp. n.

Figure 54. Distribution map of the genus Hylekobolus gen. n.

Figure 57. Hylekobolus griseus sp. n., A–E male paratype, F–I male holotype. A head, lateral view B legs 1–7 and gonopods, ventral view C antennal groove D legs 1–7, ventral view E telson F anterior gonopod, anterior view G left posterior gonopod, anterior view H anterior gonopod, posterior view I left posterior gonopod, posterior view.Apo = apodeme; av = anal valves; Co = collum; Cx = coxite; Go = gonopods; IL = incisura lateralis; Md = mandible; Pre = preanal ring; sf = setiferous foveolae; St = sternite; T = telopodite. Scale bars = 1 mm.

Figure 58. Hylekobolus albicollaris sp. n., male holotype. A head, lateral view B male legs 1–7, ventral view C telson D anterior gonopod, anterior view E left posterior gonopod, anterior view F anterior gonopod, posterior view G left posterior gonopod, posterior view. Apo = apodeme; av = anal valves; Co = collum; Cx = coxite; Md = mandible; Pre = preanal ring; St = sternite; sub = subanal scale; T = telopodite. Scale bars = 1 mm.