Granitobolus 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 : 66-70

publication ID 10.3897/zookeys.19.221

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Granitobolus Wesener

gen. nov.

Granitobolus Wesener View in CoL , gen. n.

Type species: Granitobolus endemicus View in CoL sp. n.

Other species included:

G. andohahelensis View in CoL sp. n.

Diagnosis: telopodite tip of posterior gonopods in Granitobolus uniquely shaped, resembling a duck’s head with an acutely projecting beak ( Fig. 37M View Figure 37 ). Adults with 37 or 38 body rings, lowest number of any Malagasy genus of Spirobolida . Natural colour usually contrasting, with red appendages, dark mesozonites and greyish or light brown metazonites ( Figs 37 View Figure 37 A–D, 38A). Shares numerous characters only with species of the genus Pseudocentrobolus : a stout preanal process which extends beyond anal valves ( Fig. 37F View Figure 37 ), well-developed lips on the anal valves, thick moniliform body rings which widely overlap each other reaching the metazonite ( Fig. 37C View Figure 37 ), rectangular extensions ( Fig. 37F View Figure 37 ) on the posterior margins of the rings and a greatly enlarged collum, which is ventrally longer than body ring 2. Gnathochilarium with a subdivided mentum and a single sclerotized ledge on each stipites ( Fig. 37H View Figure 37 ), like in Flagellobolus , Riotintobolus , Pseudocentrobolus , Caprobolus gen. n., Alluviobolus gen. n., Ostinobolus gen. n. Both genera possess, however, completely different posterior gonopods.

Distribution and ecology: species of Granitobolus have been recorded from numerous rainforest and littoral rainforest sites in Southeast Madagascar. Unfortunately, mature males could be collected only from three sites (Andohahela-Vasiha, Manantantely and the Ambatotsirongorongo Mountain, Fig. 30 View Figure 30 ). At least single immature specimens found in the littoral forest of Mandena and the Sainte Luce fragments S8 and S9 might represent another undescribed species because of their uniformly dark, almost black coloration. The specimens from Isaka-Ivondro (Andohahela), Ebosika (Andohahela) and Ivorona (Anosyenne) closely resemble G. andohahelensis sp. n. Except for two or three isolated specimens, which were collected on trails, all other specimens of Granitobolus were taken from large, massive, partly overgrown granitic outcrops. Specimens were collected in large numbers from thin layers of roots covering the stones. On a single rock, specimens of all sizes and both sexes were found; however, mature males remained rare. This might be related to the beginning of the dry season (June), when the collections were conducted. Both holotypes were infested with rather long nematodes (P, Fig. 38B View Figure 38 ). The legs and body rings of G. endemicus sp. n. holotype are also covered with fungi.

Description. Males: length up to 35 mm (broken), diameter up to 3.3 mm. 37 or 38 podous rings. Females: length up to 48 mm, diameter up to 4.85 mm. 37 or 38 podous rings. Length-width ratio in both sexes 1:10. Apodous rings absent in all adult specimens.

Colour: mesozona dark olive green or blackish ( Fig. 37A View Figure 37 ), metazona much light- er, brown to yellow ( Fig. 37C View Figure 37 ). Head, antennae and legs red (faded to light brown in some specimens).

Head: each eye large, with circa 35–40 ocelli arranged in 6 or 7 vertical rows ( Figs 37D, G View Figure 37 ). Labrum with standard three irregular teeth and one row of 10–12 stout marginal setae ( Fig. 37E View Figure 37 ). Clypeus with two setiferous foveolae on each side ( Fig. 38B View Figure 38 ). Length of antennae sexually dimorph, protruding back to ring 2 (females) or 4 (males, Figs 37A, D View Figure 37 , 38A View Figure 38 ). Relative lengths of antennomeres: 1<2=3=4=5<6 ( Fig. 37G View Figure 37 ). Terminal antennomere with four large sensory cones located together inside a membranous area. Antennomere 5 latero-apically with three or four rows, antennomere 6 with two rows of sensilla basiconica.

Gnathochilarium unusual ( Fig. 37H View Figure 37 ). Lamellae linguales each with two standard setae located behind one another. Stipites each with three apical setae. Mentum basally subdivided by a well-visible suture ( Fig. 37H View Figure 37 ). Stipites each towards mentum with a wide sclerotized ledge ( Fig. 37H View Figure 37 ). Hypopharyngeal crest with a field of spine-like structures. Central pads of endochilarium separated by a step into two levels. Medial palps with a large group of sensilla each, located towards hypopharyngeal crest.

Mandible: external tooth simple, rounded; mesal tooth with three cusps. Four pectinate lamellae. Molar plate with numerous (10 or 11) small and shallow transverse furrows.

Collum: smooth, laterally longer than body ring 2. Lobe enlarged, covering antenna and part of head ( Figs 37D View Figure 37 , 38A View Figure 38 ).

Body rings: moniliform, overlapping up to anterior half of mesozona. Metazona of swollen appearance, width larger than pro- or mesozona ( Figs 37 View Figure 37 A–C). Posterior margin of rings slightly excavated into rectangular extensions ( Fig. 37F View Figure 37 ). Ozopores starting at ring 6, touching suture between mesozona and metazona ( Fig. 37D View Figure 37 ).

Telson: anal valves with well-developed lips and micropunctation, but with neither grooves, nor setae. Preanal process well-rounded or sharp, extending beyond anal valves ( Figs 37F View Figure 37 , 38C View Figure 38 ). Subanal scale inconspicuous.

Legs: coxae 1 and 2 elongated, fused with sternum, podomeres from prefemur to tarsus in both sexes each with 4–10 ventral/mesal setae. Length of midbody legs circa 1.0 times body diameter in males ( Fig. 37J View Figure 37 ), 0.6 times body diameter in females ( Fig. 37K View Figure 37 ). Each podomere with an apical, ventral seta ( Fig. 37K View Figure 37 ). Coxae 3 and beyond of rectangular shape ( Fig. 37I View Figure 37 ). Tarsus with a stout dorso-apical seta and a pair of stout ventro-apical ones in males, three pairs of setae in females. In females apical setae pair stout, others successively much smaller.

Male sexual characters: tarsi starting at leg 3 up to midbody legs wide and with a large tarsal pad not protruding past base of claw ( Fig. 37J View Figure 37 ). Tibia shorter than in females ( Figs 37J, K View Figure 37 ). Coxae 3–7 unmodified ( Figs 37E View Figure 37 , 38B View Figure 38 ).

Anterior gonopods: median sternal projection triangular, with a wide, rectangular tip ( Figs 37L View Figure 37 , 38D View Figure 38 ). Sternite never protruding as high as coxite. Coxite wide, smoothly rounded, laterally curving around telopodite, but only extending slightly at posterior side ( Figs 37N View Figure 37 , 38F View Figure 38 ). Coxite anteriorly almost completely covering telopodite. Coxite processes absent, but mesal margin towards sternite sometimes projecting ( Fig. 37L View Figure 37 ). Telopodite with a short, well-rounded, laterally curved process, which only slightly projects above telopodite margin and never protrudes above coxite margin ( Figs 37N View Figure 37 , 38F View Figure 38 ).

Posterior gonopods in situ almost completely covered by anterior gonopods. Suture between coxite and telopodite well-visible ( Fig. 37O View Figure 37 ), sternite triangular and sclerotized but often hidden by a large, finger-shaped coxite process ( Fig. 37O View Figure 37 ). Finger-shaped process not curved, running parallel to basal margin ( Figs 37O View Figure 37 , 38G View Figure 38 ). Telopodites arranged face-to-face with one another ( Fig. 37M View Figure 37 ). Shape of apical part resembling ‘beak’ ( Figs 37M View Figure 37 , 38E View Figure 38 ). Beak acutely projecting, partly sclerotized and carrying sperm canal ( Fig. 38G View Figure 38 ). Telopodite between apex and beak with a small membranous area ( Fig. 37M View Figure 37 ), in basal half mesally of sperm canal with a lower elevated area ( Fig. 37M View Figure 37 ).

Female sexual characters: vulva simple, with a small, poorly sclerotized operculum at base, bivalve-like. Posterior valve apically slightly overlapping anterior one. Both valves smooth, sensory cones absent. Each valve basally towards opening with two rows of setae.

Etymology: Granitobolus , masculine, after Granit (German for granite) for the special habitat, granitic outcrops, on which species of this genus were found, and -bolus.












Granitobolus Wesener

Wesener, Thomas, Enghoff, Henrik & Sierwald, Petra 2009

G. andohahelensis

Wesener & Enghoff & Sierwald 2009
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