Friday, December 15, 2017

[Diplopoda • 2017] Sphaeromimus kalambatritra & S. midongy • Integrative Description of Two New Species of Malagasy Chirping Giant Pill-millipedes, Genus Sphaeromimus (Sphaerotheriida: Arthrosphaeridae)


Sphaeromimus kalambatritra
 Moritz & Wesener, 2017

  DOI:  10.5852/ejt.2017.381 

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 pill-millipede. 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 Wesener, 2014 and 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.

Keywords: biodiversity; COI; island gigantism; Kalambatritra; Midongy


Order Sphaerotheriida Brandt, 1833
Family Arthrosphaeridae Jeekel, 1974
Genus Sphaeromimus de Saussure & Zehntner, 1902


Sphaeromimus kalambatritra sp. nov.

Diagnosis: Large, massive, brown Sphaeromimus, > 50 mm long. Differing from all other species of Sphaeromimus in having five stridulation ribs on the male harp (as in S. musicus (Saussure & Zehntner, 1897) and S. vatovavy Wesener, 2014) in the following characters: tarsus of leg 3 without an apical spine, coxal process almost absent, posterior telopod with two membranous lobes. >80 ocelli. 

Etymology: The specific epithet ‘kalambatritra’, noun in apposition, refers to the type-locality, the Réserve Spéciale de Kalambatritra (Fig. 11).

Distribution: Only known from the type-locality, the Réserve Spéciale de Kalambatritra, which is a mountainous rainforest (Fig. 11). In the same habitat, two undetermined giant pill-millipede species of the genus Zoosphaerium occur sympatrically. 


Sphaeromimus midongy sp. nov. 

 Diagnosis: Large, massive, dark brown Sphaeromimus, >50 mm long. Differing from the only known species of Sphaeromimus with six stridulation ribs on the male harp (S. ivohibe Wesener, 2014), with which it also shares the two lobes on the movable fi nger of the posterior telopod, in the following characters: large difference in size and colour pattern, a densely pubescent male gonopore, legs 4–21 with 14 or 15 ventral spines (12 in S. ivohibe), and endotergum with two dense rows of long marginal bristles (single row in S. ivohibe).

Etymology: The specific epithet ‘midongy’, noun in apposition, refers to the type-locality, the Parc National de Midongy.

 Distribution: Only known from the type-locality, the Parc National de Midongy (Fig. 11). Mountainous rainforest.


Leif Moritz and Thomas Wesener. 2017. Integrative Description of Two New Species of Malagasy Chirping Giant Pill-millipedes, Genus Sphaeromimus (Diplopoda: Sphaerotheriida: Arthrosphaeridae). European Journal of Taxonomy.  381; 1-25. DOI:  10.5852/ejt.2017.381
Thomas Wesener, Daniel Minh-Tu Le and Stephanie F. Loria. 2014. Integrative Revision of the Giant Pill-millipede Genus Sphaeromimus from Madagascar, with the Description of Seven New Species (Diplopoda, Sphaerotheriida, Arthrosphaeridae). ZooKeys. 414: 67-107  DOI: 10.3897/zookeys.414.7730

 

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