Zehntnerobolus Wesener, 2009

Wesener, Thomas, 2011, Re-discovery after more than a century: a redefinition of the Malagasy endemic millipede genus Zehntnerobolus, with a description of a new species (Diplopoda, Spirobolida, Pachybolidae), Zootaxa 3018, pp. 21-26 : 22-23

Genus Zehntnerobolus Wesener, 2009

Type species: Spirobolus rubripes de Saussure & Zehntner, 1897, monotypic Other species included: Zehntnerobolus hoffmani n. sp.

Taxonomic position. The presence of a sclerotized sternite connecting the posterior gonopods ( Fig. 3 E) and the absence of apodemes on the anterior gonopods ( Figs 2 E, 3C) place Zehntnerobolus in the family Pachybolidae , suborder Trigoniulidea. The closest relative of Zehntnerobolus might be found among other small-bodied Malagasy Spirobolida .

Re-diagnosis. The description of a second species of Zehntnerobolus together with a more detailed morphological study allows a re-diagnosis of the genus previously monotypic. Telopodite process of anterior gonopod slender and curved laterally ( Figs 2 E, 3C, D), a unique character of Zehntnerobolus . Sperm canal of posterior telopod apically free, protruding above lateral margin ( Figs 3 E–G). Among Malagasy Pachybolidae , a free sperm canal also exists in Flagellobolus and Caprobolus . Shares a gnathochilarium with a transverse ridge subdividing mentum with the Malagasy genera Flagellobolus , Riotintobolus , Pseudocentrobolus , Granitobolus , Caprobolus , Alluviobolus and Ostinobolus . Shares a torsion of telopodite of posterior gonopod with discharge opening of efferent duct (sperm canal) turned laterally instead of mesally with Riotintobolus and Alluviobolus .

Distribution and ecology. Apparently a rare genus. Recent collection efforts by the California Academy of Sciences and the Field Museum at more than 250 localities throughout Madagascar only resulted in the collection of a single sample with two specimens, described below, 385 km south of the other know historic localities, from Ivohibe ( Fig. 1 ). As suggested previously (Wesener et al. 2009B), and indicated by the collection method of the recent specimens (sifting of leaf litter), this genus probably lives on the surface of (or inside) the leaf litter.

Figures

FIGURE 1. Distribution map of Zehntnerobolus Wesener, 2009. Elevation in meters.

FIGURE 2. Zehntnerobolus hoffmani n. sp., holotype (FMMC 4014), multi-layer photographs. A: head and anterior five rings, lateral view; B: midbody with ozopores, lateral view; C: posterior body end; D: head and anterior five rings, ventral view; E: anterior gonopods, posterior view; F: posterior gonopods, posterior view; G: posterior gonopods, anterior view. Abbreviations: av = paraproct; Co = collum; Cx = coxite; Gn = gnathochilarium; IL = incisura lateralis; Md = mandible; Mes = mesozonite; Met = metazonite; O = ozopore; Pre = epiproct; sc = efferent duct (sperm canal); St = sternite; sub = hypoproct; T = telopodite; Tp = telopodite process. Not to scale.

FIGURE 3. Zehntnerobolus hoffmani n. sp., holotype (FMMC 4014), schematic drawings. A: posterior body end; B: left midbody leg, posterior view; C: anterior gonopods, anterior view; D: anterior gonopods, posterior view; E: right posterior gonopod, overview, posterior view; F: right posterior gonopod, apical part, mesal view; G: right posterior gonopods, apical part, anterior view. Abbreviations: av = paraproct; Cx = coxite; Cx-p = coxite process; mem-fr = membraneous fringe; Pre = epiproct; sc = efferent duct (sperm canal); St = sternite; sub = hypoproct; T = telopodite; Tp = telopodite process. Scale bars = 1 mm.