Colossobolus 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 : 17-23

publication ID	https://doi.org/ 10.3897/zookeys.19.221
publication LSID	lsid:zoobank.org:pub:C473F9F6-1AE7-4B3F-B17F-CA1C2709010C
DOI	https://doi.org/10.5281/zenodo.3791384
persistent identifier	https://treatment.plazi.org/id/3F5F1E9A-F3BE-44F4-AB34-62DB25472FBD
taxon LSID	lsid:zoobank.org:act:3F5F1E9A-F3BE-44F4-AB34-62DB25472FBD
treatment provided by	Plazi
scientific name	Colossobolus Wesener
status	gen. nov.

Treatment

Colossobolus Wesener View in CoL , gen. n.

urn:lsid:zoobank.org:act:3F5F1E9A-F3BE-44F4-AB34-62DB25472FBD

Type species: Colossobolus semicyclus View in CoL sp. n.

Other species included:

C. oblongopedus View in CoL sp. n.

C. giganteus View in CoL sp. n.

C. minor View in CoL sp. n.

C. litoralis View in CoL sp. n.

C. aculeatus View in CoL sp. n.

C. pseudoaculeatus View in CoL sp. n.

Diagnosis: distinguished by the slender telopodite process of anterior gonopods and the disc-like shape of posterior gonopod telopodite which is always divided into two branches. The sperm canal runs through the mesal branch and the area between both branches is basally membranous ( Fig. 9F View Figure 9 ). Shares a large body size (90–170 mm) and an aposematic red/black colour pattern ( Figs 9A View Figure 9 , 13A View Figure 13 ) with Aphistogoniulus Silvestri, 1897 , Madabolus Wesener & Enghoff, 2008 , Corallobolus and Sanguinobolus . Male tarsal pads are prominently developed. Shares a wide and short coxite process of the anterior gonopods ( Fig. 9D View Figure 9 ) with Sanguinobolus , while this process is slender in Corallobolus ( Fig. 2A View Figure 2 ), and slender as well as longer than the telopodite in Aphistogoniulus .

Distribution and ecology: species of Colossobolus have been recorded from littoral, dry and subhumid forests in northern Madagascar ( Fig. 10 View Figure 10 ). Two different Colossobolus species occur sympatrically at numerous sites, but no Colossobolus species have been found in rainforests. Species of Colossobolus and Aphistogoniulus occurred sympatrically on at least one site. Species of Colossobolus are probably active on the soil surface and might even climb trees because of their long legs, aposematic colour pattern and the fact that some species were caught in pitfall traps.

Description. Males: length up to 165 mm, diameter up to 12.0 mm, 47–52 rings. Females: length up to 128 mm, diameter up to 15.5 mm, 49–52 rings. Apodous rings absent in all adult specimens.

Coloration (after short time in alcohol): prozona and mesozona red or reddishbrown (faded to grey because of light or alcohol exposure in some specimens), metazona dark brown or black ( Fig. 17 View Figure 17 ). Ozopores surrounded in some specimens by a large black spot. Telson (also faded to grey in some specimens), head, antennae, gonopods and legs always red ( Figs 9A, C View Figure 9 ).

Head: each eye with circa 35–40 ocelli arranged in 6–9 vertical rows ( Fig. 9A View Figure 9 ). Labrum with circa three irregular teeth and one row of 10–12 stout marginal setae ( Fig. 9B View Figure 9 ). Clypeus with two setiferous foveolae on each side ( Fig. 9B View Figure 9 ). Antennal cavity present, not extending below eye ( Fig. 13A View Figure 13 ). Antennae short, reaching back to ring 3 or 4 ( Fig. 9A View Figure 9 ). Relative lengths of antennomeres: 1<<2>>3=4=5=6, antennomere 2 longest ( Fig. 11A View Figure 11 ). Terminal antennomere with four large sensory cones located together inside a membranous area ( Fig. 11C View Figure 11 ). Antennomere 5 latero-apically with four rows, antennomere 6 with three rows ( Fig. 11B View Figure 11 ) of sensilla basiconica.

Gnathochilarium: of usual spirobolidan shape. Lamellae linguales each with two standard setae located behind one another. Stipites each with three apical setae ( Fig. 13B View Figure 13 ). Mentum with several transverse ridges in basal half. Palpi of gnathochilarium with numerous sensilla. Hypopharyngeal crest with a field of spine-like structures.

Central pads of endochilarium separated by a step into two levels, group of 10–12 sensilla located apically in recessed area. Medial palps with a large group of sensilla each, located towards hypopharyngeal crest ( Fig. 11D View Figure 11 ).

Mandible: external tooth simple, rounded; mesal tooth with three cusps. Five pectinate lamellae. Mesal margin of pectinate area with circa four rows of small slender spines. Molar plate with numerous (7–10), very shallow transverse furrows ( Fig. 12A View Figure 12 ).

Collum: smooth, laterally not protruding as far as ventral surface of body ring 2 ( Figs 9A, B View Figure 9 ).

Body rings: mostly smooth, with some irregular punctation and some transverse impressions on mesozona. Metazona and mesozona ventrally with deep longitudinal impressions. Ozopores starting at ring 6, located closely in front of, but not touching suture between mesozona and metazona. Ozopore on ring 6 located much more ventrally than subsequent ozopores.

Telson: anal valves with well-developed lips and micropunctation, but with neither grooves nor setae. Preanal process well-rounded or sharp, but never extending beyond anal valves ( Fig. 9C View Figure 9 ). Subanal scale inconspicuous.

Legs: coxae 1 and 2 elongated and fused with sternum, podomeres from prefemur to tarsus in both sexes each with 4–10 ventral/mesal setae. Length of midbody legs circa 1.2 times body diameter in males, circa 0.8 times body diameter in females. Each podomere with an apical, ventral seta. Coxae 3 and beyond of rectangular shape ( Fig. 18D View Figure 18 ). Tarsus with a stout dorso-apical setae and in males a pair of stout ventroapical setae, in females with three pairs of setae, of which apical pair stout, others successively much smaller.

Male sexual characters: tarsi 3 and beyond with a large tarsal pad not protruding past base of claw. Coxae 3–7 with a short process each, this process protruding posteriorly, but never overlapping adjacent one. Processes on coxae 3 and 4 slightly longer than those on coxae 5–7 ( Fig. 9B View Figure 9 ). Gonopods not projecting past body rings ( Fig. 16A View Figure 16 )

Anterior gonopods: sternite triangular, well-rounded or only slightly tapering ( Fig. 9D View Figure 9 ), protruding almost as high as coxite. Coxite broad, smoothly rounded, laterally curving around telopodite, extending only slightly towards posterior side, where it is laterally visible as a small triangular sclerite ( Fig. 9E View Figure 9 ). Mesal coxite process short, wide and well-rounded ( Fig. 9D View Figure 9 ). Telopodite mesally elongated into a long, wide, wellrounded process ( Fig. 9D View Figure 9 ). Mesal margin basally of telopodite process always elevated, sharp-edged, in some species widely protruding ( Figs 9E View Figure 9 , 18F View Figure 18 ). A large, deep groove usually present in basal part of telopodite ( Fig. 13D View Figure 13 ). Apodeme very small, located basally of sternite and entirely covered with muscle tissue ( Fig. 15C View Figure 15 ).

Posterior gonopods in situ almost completely covered by anterior gonopod. Posterior gonopods clearly divided into coxite and telopodite. Sternite sclerotized and well-visible ( Fig. 15F View Figure 15 ). Coxite basally wide, mesally with a single groove ( Fig. 14B View Figure 14 ) protruding into a stem towards telopodite. Telopodite always developed as a special disc, separated from coxite stem by a membranous area ( Figs 9 View Figure 9 F–I). Telopodites either standing face-to-face ( Figs 9F, G View Figure 9 ), or parallel ( Figs 19A, B View Figure 19 ) to one another. Telopodite comprising of three components: (1) median membranous area, (2) lateral branch, (3) mesal main branch with membranous folds. Sperm canal discharging into membranous folds proximally on main branch. Telopodite in some species basally with a finger-shaped process, termed here as a “coxite branch” ( Figs 9F, G View Figure 9 ). It is unclear whether the coxite branch belongs to the telopodite or coxite.

Female sexual characters: vulva simple, with a small, poorly sclerotized operculum at base, bivalve-like ( Fig. 12B View Figure 12 ). Anterior valve shorter than posterior one. Both valves smooth, lacking sensory cones. Each valve basally towards opening with two or three rows of setae ( Fig. 12B View Figure 12 ).

Etymology: Colossobolus , masculine, is composed of colossus, which refers to the extraordinary large size of species in this genus, and - bolus.