Colossobolus olympiacus ( Karsch, 1881 ) Wesener, 2024

Wesener, Thomas, 2024, Five new species and numerous locality records of Spirobolida millipedes from Madagascar (Diplopoda, Spirobolida, Pachybolidae), Zootaxa 5529 (3), pp. 461-486 : 464-466

Colossobolus olympiacus ( Karsch, 1881) new combination

Fig. 1A–H

Spirobolus olympiacus Karsch, 1881: 64 (first description, female)

Spirobolus (Trigoniulus) olympiacus deSaussure & Zehntner 1902: 129 (list)

Trigoniulus olympiacus Enghoff 2003: 624 (list)

Spirobolus olympiaceus (sic!) Wesener et al. 2009a: 120 (comment)

Trigoniulus olympiacus Wesener & Enghoff 2022: 929 (list)

Material examined. 1 M, BLF 7999 (CASENT 9005459). Madagascar, Province Antsiranana, Nosy Be, Parc National de Lokobe , 4.95 km 125° ESE Hellville, rainforest, 0–200 m, 13°24’56” S, 048°18’27” E, coll. D. Andriamalala, C. Griswold, H. Ratsirarson & D. Silva, hand collecting, 13–16.iii.2003 . 1 M, 2 F, BLF30972 (CASENT 9068308), Antsiranana, Galoko chain, Mont Galoko , rainforest, 520 m, 13°35’06’’ S, 048°43’05’’ E, coll. B.L. Fisher et al., 21.ii.2013 .

Rediagnosis. Colossobolus species with a finger-shaped coxite branch on the posterior gonopod ( Fig. 1F, G ), like in C. semicyclus Wesener, 2009 , C. oblongopedus Wesener, 2009 and C. giganteus Wesener, 2009 . Anterior gonopods lacking a retrorse process on the mesal margin of the telopodite ( Fig. 1D, E ), like in C. oblongopedus . Posterior gonopods most similar to those of C. oblongopedus and C. giganteus , but differing in the narrowly elongated tip of the lateral branch, as well as the apical part of the mesal branch. Male legs with tarsal pads ( Fig. 1H ).

Redescription (based on topotypic material from Nosy Be)

Measurements: 56+0 body rings plus telson. 178 mm long, 12.15 mm wide (midbody, widest).

Colour: mesozonite orange-grey, metazonite black, telson blood red. Ozopores black, head, antenna, mouthparts red. Collum at margins black, surface red ( Fig. 1A ). Legs red to greyish.

Head with 35/36 black ommatidia ( Fig. 1A ). Vertical suture not going through whole head, head with the usual 2+2 setiferous foveolae ( Fig. 1B ). Gnathochilarium typical for the order, lamellae linguales each with 1+1 seta behind one another, stipes each with three setae ( Fig. 1B ). Mandible basal lobe not projecting. Antennae short, protruding back to third body ring ( Fig. 1A )

Ozopore starting at ring 6, located on suture between meso- and metazonite.

Legs in male on coxae 3 and 4 with short conical process ( Fig. 1B ), coxae 5–7 normal, tarsal pads present, starting at leg 3 ( Fig. 1G ). Legs 8+ with femur cylindrical, as long as tarsus, podomere length 1<2<3>4=5<6. Each podomere apically with one or two spines, tarsus with wide claw and single short apical spine ( Fig. 1H )

Telson: preanal scale very slightly projecting in well-rounded process, not projecting beyond anal valves ( Fig. 1C ). Anal valves with well-developed lips and large groove. Subanal scale inconspicuous.

Anterior gonopod sternite elongated into a wide, broadly rounded-triangular lobe ( Fig. 1D ). Mesal process of coxite weakly developed, protruding into a short, wide lobe with a rounded tip ( Fig. 1D ). Telopodite on posterior side basally with a circular groove ( Fig. 1E ). Telopodite process long and well-rounded ( Fig. 1E ), mesal margin laterally sharp ( Fig. 1E ).

Posterior gonopods telopodites positioned parallel to one another. Coxite relatively short, wide, stout, less than half as long than lateral branch of telopodite ( Fig. 1F, G ). Latter slightly curved, basally wide, at midpoint tapering, tip again wide and swollen ( Fig. 1F ). Central membranous area developed as a short, wide, well-rounded lobe ( Fig. 1F ). Mesal main branch short, basal part running parallel to lateral branch. Apical part of main branch slender, extending towards and touching lateral branch ( Fig. 1G ). Mesal margin of main branch with a well-rounded, overlapping membranous fold ( Fig. 1F ). Main branch laterally with a small, irregular-shaped membrane ( Fig. 1F, G ). Lateral branch apically strongly tapered, slender ( Figs 1 F, G ).

Intraspecific variation. Specimens from the Galoko Mountain Chain have only 52–54 body rings and are with a length of 169 mm, a width of 11.35 mm in the male and a length of 144 mm length with a width of 12.4 mm in the female shorter than those from Nosy Be.

Remarks. At both localities found in sympatry with Aphistogoniulus erythrocephalus ( Pocock, 1893) .

Spirobolus olympiacus Karsch, 1881 was one of the few remaining nomina dubia of the Spirobolida from Madagascar ( Wesener et al. 2009a). The short first description is the only known record, based on a female from Nosy Be, and mentions few characters aside from the large size (215 mm) and the presence of 57 rings. The holotype (and only known specimen) seems unfortunately lost. It is no longer in the collections of the museum in Berlin (Mark Judson, pers. comm.), and it is also one of the few not listed in the first Berlin Myriapoda type catalogues, neither under Spirobolida nor Spirostreptida ( Moritz & Fischer 1974, 1975). The discovery of a massive Spirobolida from Nosy Be (albeit “only” 180 mm in length) with 56 rings plus telson allows here a redescription of this enigmatic species.

Figures

FIGURE 1. Colossobolus olympiacus (Karsch, 1881), n. comb., topotype (CASENT 9005459). A. Multi-layer photograph, male anterior body, lateral view; B. Multi-layer photograph, male leg pairs 1–7, ventral view; C. Multi-layer photograph, male posterior body end with telson; D. Right anterior gonopod, anterior view; E. Right anterior gonopod, posterior view; F. Left posterior gonopod, anterior view; G. Left posterior gonopod, posterior view; H. Male right midbody leg, posterior view. Abbreviations: Apo = apodeme; av = paraprocts; bb = basal branch of posterior gonopod; Co = collum (ring 1); Cx = coxite; Fe = femur; fs-p = finger-shaped process; Gn = gnathochilarium; Gr = groove; ma = membranous area on posterior gonopod; Md = basal joints of mandible; oz = ozopore; Po = postfemur; Pre = epiproct; sf = setiferous foveolae; St = sternite; sub = hypoproct; T = telopodite; T-Lbr = lateral branch of telopodite; T-mbr = main branch of telopodite; Ta = tarsus; ta-p = tarsal pad; Ti = tibia; numbers refer to leg pair number. Scale bars = 1 mm.