Colossobolus semicyclus 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 : 25-26

Colossobolus semicyclus Wesener , sp. n.

urn:lsid:zoobank.org:act:8205B095-B802-46B7-8BA7-BEF078E551A8

Material examined: 2 ♂, 2 ♀, 1 imm. Holotype: 1 ♂ (120 mm long), CAS BLF 10114a. Madagascar, Province Antsiranana, Forêt d’Antsahabe , 11.4 km 275°W Daraina, tropical dry forest, 550 m, 13°12’42” S, 049°33’24” E, leg. B. L. Fisher et al., 12.XII.2003 . Paratypes: 1 ♀, 1 imm., CAS BLF 10114a, same data as holotype ; 1 ♂, 1 ♀, FMMC 5488 , Province Antsiranana, near Analamozava River , 7.5 km SW Daraina, undisturbed humid lowland forest, 325–600 m, 13°15.3’ S, 49°37.0’ E, leg. S. Goodman, 3–10.XI.2001, pitfall trap .

Other material examined: 2 ♂, 1 ♀, CAS BLF 10877a, Forêt de Binara, 9.1 km SW Daraina, rainforest, 650–800 m, 13°15’48” S, 049°36’12” E, leg. B. L. Fisher, 19.XI.2004.

Differential diagnosis: Colossobolus semicyclus sp. n. cannot be separated from other sympatric Colossobolus species by external features alone ( Fig. 10 ). Differs from all other species in the unique shape of the posterior gonopod telopodite ( Figs 9 F–I) and in the presence of a well-rounded coxite process on the anterior gonopod. Shares with C. oblongopedus sp. n. and C. giganteus sp. n. a finger-shaped coxite process on the posterior gonopods.

Description. Measurements: males with 49–52 body rings, circa 120 mm long, 9.7–11.4 mm wide. Females with 49–52 body rings, 100–125 mm long, 10.5–11.0 mm wide.

Coloration affected by alcohol. Head, legs, antennae and telson red. Meso- and metazonites of body rings reddish-brown, posterior margin with a thin, dark brown line ( Figs 9 A–C). Antennae protruding back to ring 3 ( Fig. 9A ). Male coxal processes present on coxae 3 and 4, well-developed. Coxae 5–7 with visible, but short processes ( Fig. 9B ).

Preanal process well-rounded, not projecting ( Fig. 9C ).

Anterior gonopod sternite elongated into a wide, broadly rounded lobe ( Fig. 9D ). Mesal process of coxite weakly developed, protruding into a short wide lobe which slightly extends beyond sternite ( Fig. 9D ). Telopodite on posterior side basally with a circular groove ( Fig. 9E ). Telopodite process long and relatively slender. Mesal margin laterally sharp-edged, but not projecting ( Fig. 9E ).

Posterior gonopods unique ( Figs 9 F–I). Telopodites positioned face-to face with one another. Coxite branch relatively short, wide and stout ( Figs 9 F–I). Lateral branch of telopodite curved, forming a ‘C’ together with coxite branch. Central membranous area protruding ( Figs 9F, H ). Mesal main branch well-developed, apical part overlapping lateral branch ( Figs 9G, I ). Mesal margin of main branch with two overlapping membranous folds. Membranous folds large, well-rounded, forming a half-circle ( Figs 9G, I ).

Intraspecific variation: animals from the type series (Forêt Antsahabe) differ greatly in size from those collected only some kilometers away in an area close to the Analamozava River. Specimens from the type series have 52 body rings while those from the Analamozava River have only 49. Specimens from Antsahabe are approximately 10 mm longer but 1 mm slimmer than those from the Analamozava River. Males from both localities show identical gonopods. Those differences can probably be accounted for by the fact that the habitat on the Antsahabe site is much drier than the Analamozava River site. However, more specimens from both sites are necessary to further refine this intraspecific variation.

Distribution and ecology: this species has hitherto been recorded only in dry and subhumid forests at mid-altitudes (325–800 m) around Daraina ( Fig. 10 ). C. semicyclus sp. n. occurs at Antsahabe sympatrically with C. oblongopedus sp. n., at the Analamozava river site sympatrically with C. aculeatus sp. n.

Etymology: semicyclus , adjective, refers to the uniquely shaped posterior gonopod telopodite.

Figures

Figure 9. Colossobolus semicyclus sp. n., male holotype. A head B legs 1–7, ventral view C telson D anterior gonopod, anterior view E anterior gonopod, posterior view F left posterior gonopod, anterior view G left posterior gonopod, posterior view H posterior gonopod, anterior view I posterior gonopod, posterior view. av = anal valves; Co = collum; Cx = coxite; Cx-br = coxite branch; Gn = gnathochilarium; ma = membranous area; Md = mandible; ms = marginal setae; Pre = preanal ring; sf = setiferous foveolae; St = sternite; sub = subanal scale; T = telopodite; T-Lbr = telopodite lateral branch; T-mbr = telopodite main branch; Tp = telopodite process. Scale bars = 1 mm.

Figure 10. Distribution of the genus Colossobolus gen. n.