Hylekobolus brachiosauroides 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 : 102-104

Hylekobolus brachiosauroides Wesener , sp. n.

urn:lsid:zoobank.org:act:40FD10B2-63FB-4627-AAAC-6961BE9102E5

Material examined: 26 ♂, 21 ♀, 6 imm. Holotype: 1 ♂ (55 mm long), FMMC W089 , Vohimena Mountains , West slope, Ivorona, 114 m, rainforest, 24°50.026’ S, 46°56.943’ E, leg. Wesener et al., 23.V.2007 . Paratypes: 3 ♂, 4 ♀, FMMC W089 , same data as holotype ; 1 ♂, 1 ♀, ZMUC W089 , same data as holotype ; 1 ♂, ZMH W089 , same data as holotype ; 1 ♂, 1 ♀, CAS W089 , same data as holotype ; 1 ♂, ZSM W089 , same data as holotype .

Other material examined: 4 ♂, 4 ♀, W089, same data as holotype, voucher specimens deposited at the University Antananarivo ; 5 ♂, 4 ♀, 2 imm., FMMC W049 B, Andohahela, Isaka-Ivondro Sud , 46 m, rainforest, 24°49.690’ S, 46°51.971’ E, leg. Wesener et al., 08.VI.2007 ; 5 ♂, 4 ♀, 2 imm., W049B, same data as previous, voucher specimens deposited at the University Antananarivo ; 2 ♂, 2 ♀, FMMC W099 , Ambatotsirongorongo Mountain, Grand Lavasoa , rainforest, 25°5’10.23” S, 46°44’55.93” E, rainforest, leg. Wesener et al., 14.VI.2007 ; 2 ♂, 1 ♀, 2 imm., W099, same data as previous, voucher specimens deposited at the University Antananarivo .

Differential diagnosis: H. brachiosauroides differs in size and colour from the sympatric living H. albicollaris sp. n. The posterior gonopods ( Figs 55M, O ) of H. brachiosauroides differ from other, same-sized Hylekobolus species: the lateral margin carries a thick, swollen, well-rounded projection ( Fig. 55M ), a feature only shared with H. montanus sp. n. H. brachiosauroides differs from H. montanus sp. n. in the presence of a protruding apical process (x) on the posterior gonopods, a weakly protruding lateral retrorse process of the anterior gonopod ( Fig. 55N ), and a different colour pattern.

Description. Measurements: males with 50 or 51 rings, 53–62 mm long, 4.8–5.2 mm wide. Females with 50 or 51 rings, 58–72 mm long, 5.1–6.0 mm wide.

Coloration: anterior part of head and collum, posterior part of telson and posterior margin of body rings lightly red or white ( Figs 53A , 55A, C ). Legs and antennae white ( Fig. 53A ). Anterior part of body rings, telson, posterior part of head and collum black ( Figs 53A , 55A ). Eyes with 40–44 ocelli ( Fig. 55D ).

Anterior gonopod sternite basally wide, apically elevated into a triangular lobe with a triangular, wide, well-rounded tip ( Fig. 55L ). Mesal process of coxite wide and only slightly protruding ( Fig. 55L ). Apical process of telopodite large and well-rounded. Retrorse margin wide, not projecting above telopodite margin ( Fig. 55N ). Margin of apical process basally wide and projecting ( Fig. 55N ).

Posterior gonopods telopodite bent 90° ( Fig. 55O ). Lateral margin with a thick, swollen, well-rounded projection (w, Fig. 55M ). Apical process (x) apically slender, basally with a widely protruding margin ( Fig. 55M ). Membranous lobe (y) rectangular ( Fig. 55M ). Projection of sperm canal (z) long and slender, slightly curved towards apical process ( Fig. 55M ).

Intraspecific variation: coloration of the posterior margin of body ring varies in adults between white and reddish, while it is always white in imm..

Distribution and ecology: this species was found in the isolated Ambatotsirongorongo Mountain, the Andohahela Isaka-Ivondro corridor as well as on the western slopes of the Vohimena Mountain ( Fig. 54 ). H. brachiosauroides could not be collected north of the Isaka-Ivondro corridor, where H. goodmani sp. n. and H. montanus sp. n. occur. In the eastern Vohimena slopes, H. rufus sp. n. replaces H. brachiosauroides . All individuals were collected inside dead logs.

Etymology: brachiosauroides , adjective, refers to the dinosaur genus Brachiosaurus , whose neck and head closely resemble the general shape of the posterior gonopods of this millipede.

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 55. Hylekobolus brachiosauroides sp. n., A–H male paratype, I–K female paratype, L–O male holotype. A head, lateral view B legs 1–7 and gonopods, ventral view C telson D antennal groove E gnathochilarium, ventral view F gnathochilarium, mentum G gnathochilarium, stipites H, I right midbody legs Į right vulva, posterior view K right vulva, lateral view L anterior gonopod, anterior view M right posterior gonopod, anterior view N anterior gonopod, posterior view O right posterior gonopod, posterior view. Apo = apodeme; av = anal valves; Co = collum; Cx = coxite; Go = gonopods; h = head; IL = incisura lateralis; L = ledges; Md = mandible; Me = mentum; O = operculum; Pre = preanal ring; pv = posterior valve; St = sternite; St-Cx = sterno-coxite; ST = stipites; T = telopodite. Scale bars = 1 mm.