Colossobolus giganteus 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 : 28-30

Colossobolus giganteus Wesener , sp. n.

urn:lsid:zoobank.org:act:AD9F0066-DFF2-4CDC-B39E-70CF2EC97F08

Material examined: 5 ♂, 2 ♀, 1 imm. Holotype: 1 ♂ (165 mm long), FMMC 6167 , Madagascar, Province d’Antsiranana, RS d’Ankarana, Grotte des Chauves Souris , 3 km NW Mahamasina, 80 m, dry forest, 12°58’05.7’’ S, 049°07’09.6’’ E, leg. S. M. Goodman, 12.V.2003 . Paratypes: 3 ♂, 1 ♀, 1 imm., FMMC 3920 , RS Ankarana, 80 m, tropical dry forest, 12°54’32’’ S, 49°6’35’’ E, leg. B. L. Fisher et C. Griswold, 10–16. II.2001 ; 1 ♂, 1 ♀, MNHN noNumber, Province Diego-Suarez (Antsiranana), Rivière des Bois Pourris , Réc. A. Treha, 13.VII.1960 .

Differential diagnosis: the gonopods of C. giganteus are so unique that they can only be confused with C. oblongopedus . See C. oblongopedus for a comparison of the two species.

Description. Measurements: males with 52 or 53 body rings, up to 165 mm long, 10.0–12.0 mm wide. Females with 52 body rings, of unknown length (broken), 10.3– 15.5 mm wide.

Coloration affected by alcohol. Head, antennae, legs and telson red. Collum centrally dark ( Fig. 15A ). Meso- and metazonites of body rings reddish-brown. Antennae protruding back to ring 4. Male coxal processes on coxae 3 and 4 weakly developed, on coxae 5–7 short, barely visible ( Fig. 15B ). Preanal process well-rounded, not projecting.

Anterior gonopod sternite elongated into a wide, broadly rounded lobe. Apical part of lobe slightly more slender than remaining part ( Fig. 15C ). Mesal process of coxite weakly developed, protruding into a short, wide lobe with a pointed tip ( Fig. 15C ). Telopodite process long and well-rounded, basally at mesal margin with a minute, but sharp, lateral retrorse projection ( Fig. 15D ). Mesal margin laterally sharp-edged, not protruding ( Fig. 15D ).

Posterior gonopod telopodites positioned parallel to one another. Coxite branch long, wide and stout, almost as long as lateral branch of telopodite ( Figs 15E, F ). Lat-

ter not tapering, apically slightly curved mesally ( Fig. 15F ). Central membranous area present as a short, wide, well-rounded lobe ( Fig. 15E ). Main branch shorter than lateral branch, both running parallel. Apical part of main branch extending towards and touching lateral branch ( Fig. 15E ). Inner margin of main branch with two very small, well-rounded, overlapping membranous folds. Main branch laterally with a very large irregularly shaped membrane ( Fig. 15E ).

Intraspecific variation: the specimens from the MNHN of unknown locality are 3–5 mm more slender than those from Ankarana.

Distribution and ecology: C. giganteus is only known from the dry forest of Ankarana ( Fig. 10 ). The sample from the unknown locality from the MNHN suggests that C. giganteus has or had a wider distribution.

Etymology: giganteus , adjective, refers to the large size of the species. Colossobolus giganteus at 165 mm is the largest known species of the genus and one of the largest millipedes known from Madagascar.

Figures

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

Figure 15. Colossobolus giganteus sp. n., male holotype. A head, lateral B legs 1–7, ventral view C anterior gonopods, anterior view D anterior gonopods, posterior view E left posterior gonopod, anterior view F left posterior gonopod, posterior view. Apo = apodeme; Co = collum; Cx = coxite; Cx-br = coxite branch; IL = incisura lateralis; LL = lamella lingualis; ma = membranous area; Md = mandible; St = sternite; ST = stipites; T = telopodite; T-Lbr = telopodite lateral branch; T-mbr = telopodite main branch; Tp = telopodite process. Not to same scale.