Alluviobolus 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 : 77-81

publication ID 10.3897/zookeys.19.221

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Alluviobolus Wesener

gen. nov.

Alluviobolus Wesener View in CoL , gen. n.

Type species: Alluviobolus laticlavius View in CoL , sp. n.

Other species included:

A. tsimelahy View in CoL sp. n.

A. antanosy View in CoL sp. n.

Diagnosis: anterior ( Fig. 44E View Figure 44 ) and posterior gonopods ( Fig. 45I View Figure 45 ) uniquely shaped for Malagasy Spirobolida : mesal process of anterior gonopod coxite absent ( Fig. 44E View Figure 44 ); telopodite mesally protruding into slender process ( Figs 44E, G View Figure 44 ), process apically with a sharp-edged retrorse projection ( Fig. 44G View Figure 44 ). Coxite and telopodite of posterior gonopods not coaxial, telopodite slightly bended posteriorly ( Fig. View Figure 42

45I). Telopodites with a torsion, opening of sperm canal discharging apico-laterally ( Figs 45I View Figure 45 , 47G View Figure 47 ). Natural colour varies between species from brown, red to pitch-black ( Figs 42A View Figure 42 , 44C View Figure 44 ), dorsally at least on mesozonites with an orange or red stripe of species-specific width. A similar stripe is also present in Spiromimus , Caprobolus and Ostinobolus gen. n. species. Alluviobolus species share the habitus and colour pattern with species of the sympatric living genus Ostinobolus gen. n. Both genera, however, possess completely different anterior and posterior gonopods. Gnathochilarium with a subdivided mentum and a single sclerotized ledge on each stipites ( Fig. 44D View Figure 44 ), like in Flagellobolus , Riotintobolus , Pseudocentrobolus , Granitobolus , Caprobolus , Ostinobolus gen. n. A torsion of the posterior gonopods ( Fig. 45I View Figure 45 ) is also present in Zehntnerobolus ( Fig. 22G View Figure 22 ) and Riotintobolus ( Fig. 26M View Figure 26 ). A strange similarity can be observed in the posterior gonopods of Alluviobolus with drawings of Trigoniulus castaneus Attems, 1915 from New Guinea ( Attems 1915: pl. I, fig. 13).

Distribution and ecology: species of Alluviobolus were found in spiny, subhumid and humid forests or rainforests in southeast Madagascar ( Fig. 43 View Figure 43 ). The records from the spiny forest are, however, restricted to the wet alluvial of rivers and small streams, and the same species also occurs in the rainforest of Ebosika. A. laticlavius sp. n. occurs in the semi-dry forest of Petriky. All species of Alluviobolus were collected on or inside the first few centimetres of leaf litter in the forests.

Description. Males: length up to 47 mm, diameter up to 4.3 mm. 43–49 podous rings. Females: length up to 62 mm, diameter up to 6.0 mm. 43–49 podous rings.

Apodous rings absent in all adult specimens.

Colour species-specific. Dorsally at least on mesozonites always with a red or orange stripe.

Head: each eye with circa 22–25 ocelli arranged in 4 or 5 vertical rows ( Figs 44A View Figure 44 , 45A, 47A). Labrum with standard three irregular teeth and one row of 10–12 stout marginal setae. Clypeus with two setiferous foveolae on each side. Antennae of medium length, reaching back to ring 5 ( Fig. 44A View Figure 44 ). Relative lengths of antennomeres: 1<<2=3=4=5<6 ( Fig. 44A View Figure 44 ). Terminal antennomere with four large sensory cones located together inside a membranous area. Antennomere 5 latero-apically with four rows, antennomere 6 with two rows of sensilla basiconica.

Gnathochilarium unusual ( Fig. 44D View Figure 44 ). Lamellae linguales each with two standard setae located behind one another. Stipites each with three apical setae. Mentum basally subdivided by a well-developed suture ( Figs 46D, E View Figure 46 ). Stipites each towards mentum with a wide sclerotized ledge ( Fig. 46E View Figure 46 ). Palpi of gnathochilarium with numerous sensilla. Hypopharyngeal crest with a field of spine-like structures ( Fig. 46F View Figure 46 ). Endochilarium apically with 4–6, towards hypopharyngeal crest with>20 sensilla.

Mandible basal joints swollen ( Fig. 45A View Figure 45 ). External tooth simple, rounded; mesal tooth with three cusps ( Fig. 45E View Figure 45 ). Four or five pectinate lamellae. Molar plate with few (circa 5) transverse furrows, anterior three furrows greatly enlarged, posterior furrows minute ( Fig. 45E View Figure 45 ).

Collum: smooth, inconspicuous. Ventrally not protruding as far as ring 2 ( Fig. 45A View Figure 45 ).

Body rings: dorsally and laterally leather-like, meso- and metazona ventrally with numerous transverse impressions. Ozopores starting at ring 6, touching suture between mesozona and metazona ( Figs 42A, B View Figure 42 ).

Telson: preanal process absent. Anal valves with lips and micropunctation, slightly elongated posteriorly. Subanal scale inconspicuous ( Fig. 44C View Figure 44 ).

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 1.1 times body diameter in males and 0.7 times body diameter in females. Each podomere with an apical, ventral seta ( Figs 46G, H View Figure 46 ). Coxae 3 and beyond of cylindrical shape ( Figs 46G, H View Figure 46 ). Tarsus with a stout dorso-apical seta and three pairs of ventral setae.

Male sexual characters: coxae 3–7 in some species modified ( Figs 44B View Figure 44 , 45B). Tarsal pads absent.

Anterior gonopods: median sternal projection triangular and elongated with a wide tip ( Fig. 44E View Figure 44 ). Sternite always longer than coxite and telopodite, except for telopodite process. Coxite process absent. Coxite in anterior view well-visible, in posterior view only laterally present ( Fig. 44G View Figure 44 ). Telopodite mesally always with a long slender process. Tip with a sharp-edged, retrorse process ( Fig. 44G View Figure 44 ).

Posterior gonopods in situ almost completely covered by coxite and telopodite of anterior gonopod. Coxite and telopodite of posterior gonopod clearly divided ( Figs 45I View Figure 45 , 47G View Figure 47 ). Sternite sclerotized and well-visible ( Figs 44I View Figure 44 , 45I). Coxite mesally with a single groove. Joint protruding into a short stem towards telopodite, latter as long and wide as coxite, curved posteriorly ( Fig. 45I View Figure 45 ). Telopodites arranged parallel to one another. A torsion present in telopodites, sperm canal discharging apico-laterally ( Fig. 44H View Figure 44 ). Tip of telopodite mesally with a sclerite of species-specific shape (x in Figs 44H View Figure 44 , 45I, 47G).

Female sexual characters: vulva simple, bivalve-like, with a small, poorly sclerotized operculum at base ( Fig. 45D View Figure 45 ). Posterior valve apically overlapping part of anterior one. Basally on each valve towards opening with two or three rows of setae ( Fig. 45D View Figure 45 ).

Etymology: Alluviobolus , masculine, Latin, consists of Alluvium referring to the alluvial of a river where large numbers of A. tsimelahy sp. n. could be collected, and -bolus.












Alluviobolus Wesener

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

A. tsimelahy

Wesener & Enghoff & Sierwald 2009

A. antanosy

Wesener & Enghoff & Sierwald 2009
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