Zootaxa 3018: 21–26 (2011) www.mapress.com / zootaxa/ Copyright © 2011 · Magnolia Press
ISSN 1175-5326 (print edition)
Article
ZOOTAXA ISSN 1175-5334 (online edition)
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) THOMAS WESENER Zoological Research Museum A. Koenig, Section Myriapoda, Adenauerallee 160, D-53113 Bonn, Germany. E-Mail:
[email protected]
Abstract A new species of the previously monotypic Malagasy pachybolid genus Zehntnerobolus Wesener, 2009, Z. hoffmani new species, is described. The diagnosis of the genus Zehntnerobolus is updated and new characters of potential phylogenetic importance for the classification of Malagasy Spirobolida are described. The here described specimens are the first known representatives of Zehntnerobolus collected since 1900. The late discovery of another Zehntnerobolus is a clear indication of how little we know about the soil arthropod macrofauna of Madagascar. Particularly the eastern rainforest region and the north of Madagascar are still underexplored. The specimens were collected in the eastern montane rainforest more than 380 km south of the known distribution of the other Zehntnerobolus species. The collection method used, as well as morphological parameters of Zehntnerobolus indicate that its species live in the leaf litter of Malagasy rainforests. Key words: Madagascar, endemic, re-discovery, soil arthropod, montane rainforest
Introduction Madagascar, the world's third largest island, is famous for its large number of endemic animals (e.g. Vietes et al. 2009) and plants (see Goodman and Benstead 2005). The millipede fauna of Madagascar is no exception, with a high number of endemic species and genera (Enghoff 2003). Among the most fascinating invertebrates of the island are, due to their large size and often intriguing color pattern, the giant pill-millipedes (order Sphaerotheriida) and millipedes of the order Spirobolida. Until 2008, only two indigenous Spirobolida genera, Aphistogoniulus Silvestri, 1897 and Spiromimus de Saussure & Zehntner, 1901, both belonging to the family Pachybolidae (Hoffman 1980), were known from Madagascar (Enghoff 2003). The genus Aphistogoniulus includes the large-bodied (120–200 mm long) black/red/gold colored fire millipedes of the subfamily Pachybolinae (see Wesener et al. 2009A for a revision), while the genus Spiromimus includes small to medium-sized species (up to 90 mm long) and forms the monotypic subfamily Spiromiminae with potential relationships to genera found in India (see Wesener and Enghoff 2009 for a revision). Since 2008, 50 new species and 13 new genera of Spirobolida (Wesener et al. 2008, Wesener and Enghoff 2009, Wesener et al. 2009A, 2009B) have been described from Madagascar, bringing the total number of indigenous genera to 15, all of them strict Malagasy endemics (not occurring on neighbouring islands such as the Comoros [VandenSpiegel and Golovatch 2007]). All but one of the genera (Hylekobolus, Spirobolellidae) belong to the family Pachybolidae (sensu Hoffman 1980), a family displaying a Gondwanan distribution with genera occurring in Australia, SE Asia, India, Africa, and South America (Wesener et al. 2008). With 14 genera of the family restricted to Madagascar, the diversity of Pachybolidae on Madagascar surpass that of India, South America and Australia combined. Madagascar is also host to the forest with the worldwide highest Spirobolida diversity: six genera live in the south-eastern littoral forest of Sainte Luce (Wesener et al. 2009b). The relationships of most of these endemic pachybolid genera are, with some exceptions (Wesener et al. 2008, Wesener and Enghoff 2009, Pitz and Sierwald 2010), still unknown. Of the 13 genera recently described from Madagascar, only one (Zehntnerobolus Wesener, 2009) was based on a previously described species, Spirobolus (Spirostrophus) rubripes deSaussure Accepted by W. Shear: 2 Aug. 2011; published: 8 Sep. 2011
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& Zehntner, 1897. However, no new material of Zehntnerobolus was discovered in the large backlog of several institutions (see Wesener et al. 2009B). Therefore, all that is known about Zehntnerobolus is based on the original types and some additional specimens collected close to the type locality in 1900. The goal of this paper is to clarify the characteristics of Zehntnerobolus with the description of a second species of this Malagasy endemic. The addition of a second species to Zehntnerobolus, and one relatively recently collected, allows a better diagnosis of the genus than was possible in the old description based on the historic material. The discovery of this species expands the known distribution area of the genus more than 380 km to the south.
Material and methods Museum and collection acronyms: FMMC FMNH ZFMK
Millipede collection specimen code for samples at FMNH Field Museum of Natural History, Chicago, USA Zoologisches Forschungsmuseum Alexander Koenig, Bonn, Germany
Illustrations: Camera lucida drawings were made with an Olympus SZX12 stereo-microscope. Head, midbody, telson and gonopods were photographed [multi-layer] using a Microptics system (Microptics, Ashland, VA, U.S.A.) based at the FMNH, and the software Auto-Montage (Syncroscopy). Sand or non-greasy lubricating jelly (Walgreens) was used to keep small parts in place for photographs. The clear lubricating jelly can be dissolved with a quick wash in distilled water. All images were later modified using Adobe Photoshop version CS2 and assembled to plates using Adobe Illustrator version CS2. Because of the rarity of the material (only one mature male was available), scanning electron microscopy was not used to investigate characters. Molecular attempts: muscle from the male gonopods and the 7th body ring was removed from the holotype (stored for 13 years in 70% ethanol) and transferred to 95% ethanol. Total genomic DNA was extracted from the muscle tissue of dissected muscles using the DNAeasy Blood & Tissue kit from Qiagen following the manufacturer’s extraction protocol. Finally, 400 μl elution buffer was used in two elution steps, each with 200 µl buffer. The success of the elution was tested with a polymerase chain reaction (PCR) with the HCO/LCO primers for a fragment of the cytochrome oxidase I mitochondrial gene under a standard barcoding protocol (see Wesener et al. 2010). Unfortunately, no bands were visible after several PCRs that yielded clear bands for other Spirobolida species. A sequencing reaction was not attempted.
Results 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. 3E) and the absence of apodemes on the anterior gonopods (Figs 2E, 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 2E, 3C, D), a unique character of Zehntnerobolus. Sperm canal of posterior telopod apically free, protruding above lateral margin (Figs 3E–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.
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WESENER
FIGURE 1. Distribution map of Zehntnerobolus Wesener, 2009. Elevation in meters.
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.
Zehntnerobolus hoffmani Wesener new species Etymology. hoffmani, adjective, to honour the 'Altmeister' of the Diplopoda, Dr. Richard L. Hoffman. Material examined. Holotype: 1 M (FMMC 4014), Madagascar, Province Fianarantsoa, Ihorombe, R. S. Ivohibe, 6.5 km ESE Ivohibe, camp III, 22°29' 48" S, 46°57'18" E, 1575 m, montane rainforest, coll. B. L. Fisher, mini-Winkler, sifted litter (leaf mold, rotten wood), 24–30.X.1997. Paratype: 1 immature M (FMMC 4014), same data as holotype. Diagnosis: species of Zehntnerobolus differing from its congener in shape of posterior gonopods: (1) coxite separated by articulation into basis and process; (2) telopodite with apical membranous lamellae resembling a 'sail'. Z. hoffmani n. sp. differs also from Z. rubripes in the lack of sclerotized nodules on the telopodite of posterior gonopods, presence of a slender sternite of the anterior gonopods (massive in Z. rubripes), and the only weakly developed coxal processes on male leg pairs 3–5 (strongly developed in Z. rubripes). Description. Measurements: male holotype with 40 rings, circa 36 mm long, 3.2 mm wide. Male paratype (immature) with 38+2 rings. Female unknown.
Rediscovery of the genus Zehntnerobolus
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Coloration: decolorized after 13 years in ethanol. Head and antennae greyish-red (Fig. 2A), legs brown-yellow. Body rings laterally grey, except for red posterior margin (Fig. 2B), dorsally with thin red stripe. Preanal scale grey, anal valves orange-red (Fig. 2C).
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.
Head: each eye with 22–24 ocelli arranged in 6 vertical rows (Fig. 2A). Incisura lateralis open (Fig. 2A). Labrum with standard three irregular teeth and a single row of 10–12 stout marginal setae. Clypeus with two setiferous foveolae on each side (Fig. 2D). Antennae protruding back to ring 5 in males (Fig. 2D). Relative lengths of antennomeres: 1
