Integrative description of two new species of Malagasy chirping giant pill-millipedes, genus Sphaeromimus (Diplopoda: Sphaerotheriida: Arthrosphaeridae)

Abstract

Abstract. The species-rich giant pill-millipedes (Sphaerotheriida) often represent a microendemic component of Madagascar's mega-invertebrate fauna. Of the chirping genus Sphaeromimus de Saussure & Zehntner, 1902, ten species have been described. Here, we describe two new species of Sphaeromimus integratively, combining light microscopy, scanning electron microscopy, DNA barcoding and micro-CT technology for the first time in a taxonomic description of a giant pillmillipede. S. kalambatritra sp. nov. and S. midongy sp. nov. are the first giant pill-millipedes collected and described from the mountainous rainforests of Kalambatritra and Midongy. Both species show island gigantism compared to their congeners. Our analysis of the mitochondrial COI gene shows that the two species are related to one another with a moderate genetic distance (9.4%), while they are more closely related to an undetermined specimen from the forest of Vevembe (6.3% and 8.4%). They stand in a basal position with S. ivohibe S. musicus (de Saussure & Zehntner, 1897). The four aforementioned species share a high number of stridulation ribs on the male harp. Our micro-CT analysis provides a look into the head of S. kalambatritra sp. nov. and shows that non-destructive CT methods are a useful tool for studying the inner morphology of giant pill-millipedes.

The millipedes collected by the Museum "La Specola" on Madagascar 1989/1991, with the description of three new species of giant pill-millipedes (Diplopoda, Sphaerotheriida, Arthrosphaeridae)

“…DNA extraction, amplification, and sequencing were conducted under identical conditions to those of earlier studies (Sagorny and Wesener 2017, Moritz and Wesener 2017, Wesener 2018, with the COI JJ primer (Astrin and Stüben 2008) being used for both PCR and sequencing. A translation into amino acids showed a similar composition to those of related species.…”

“…Morphological and molecular studies show that the Malagasy genus Sphaeromimus is more closely related to the Indian genus Arthrosphaera, which reflects an Indian-Malagasy biogeographical affinity (Wesener and VandenSpiegel 2009, Wesener et al 2010a, 2014, Moritz and Wesener 2017. Within the family Arthrosphaeridae, the endemic Malagasy genus Zoosphaerium has the highest number of known species (67) (Wesener 2016, Sagorny and.…”

An integrative and citizen science based approach to the rediscovery and redescription of the only known high-altitude endemic Pill Millipede, Glomeris aurita Koch (Diplopoda, Glomerida)

“…Critical point drying of the specimen would probably have yielded better scan results, as was done in previous taxonomic studies ( Akkari, Enghoff & Metscher, 2015 ; Liu, Rühr & Wesener, 2017 ; Sagorny & Wesener, 2017 ; Moritz & Wesener, 2017 ), but this would impact the whole specimen and no longer be a minimally invasive technique. Manual reconstruction of certain body parts could have resulted in better illustrations, e.g., of the telopods.…”

Ecotone shifts in southern Madagascar: first barcoding data and six new species of the endemic millipede genus Riotintobolus (Spirobolida, Pachybolidae)

“…For other millipedes from Madagascar, interspecific distances are known for two genera of giant pill-millipedes (Sphaerotheriida), Sphaeromimus DeSaussure &Zehntner, 1902 andZoosphaerium Pocock, 1895. In Sphaeromimus, whose species show a distribution restricted to southern Madagascar comparable to those of Riotintobolus, interspecific distances vary mainly between 8.3-20.8% (Wesener et al 2014;Moritz and Wesener 2017). In the widespread genus Zoosphaerium, only a handful of species were sequenced (Wesener et al 2010;Sagorny and Wesener 2017;Wesener and Anilkumar 2020), with interspecific distances varying between 9.1-16.3%.…”