Zoosphaerium pseudoplatylabum, Wesener, 2009

Wesener, Thomas, 2009, Unexplored richness: discovery of 31 new species of Giant Pill-Millipedes endemic to Madagascar, with a special emphasis on microendemism (Diplopoda, Sphaerotheriida), Zootaxa 2097 (1), pp. 1-134 : 53

The Zoosphaerium platylabum species-group

Members of this species-group display a high variability in numerous morphological characters. Z. platylabum ( de Saussure & Zehntner, 1902) and Z. pseudoplatylabum , n. sp. both share an obesely enlarged movable finger of the posterior telopod (Fig. 36C). Z. solitarium , n. sp., Z. corystoides , n. sp. and Z. broelemanni , n. sp. all have slender posterior telopods (Fig. 40F) but share wide and deeply depressed lateral grooves of the thoracic shield. All these five species share a similar modified operculum of the vulva, which is elongated into two sharp-edged lobes (Fig. 45B) instead of the well-rounded lobes (Fig. 7C) displayed in all other Zoosphaerium species. Still puzzling is the position of Z. tsingy , n. sp., which is here placed preliminary in the Z. platylabum species-group, because of an aberrant position of the anal shield locking carinae shared with the other members of the platylabum -group, but lacks the modified vulva. In the Z. platylabum speciesgroup such locking carinae are located close to the laterotergites (Fig. 48B) instead of to the anal shield margin. This unusual position of the locking carinae leads to a more tightly packed sphere when the animals roll themselves in. Members of the Z. platylabum group roll into a rounder sphere than other giant pillmillipedes, which generally roll into a more or less oval sphere (Fig. 17A). This species-group was previously monotypic, while five more species could be added in this study. This species-group seems to be restricted to the Northern and Western humid forest, with the notable exception of Z. tsingy , n. sp. which was recorded from the Western dry forest (Fig. 38).