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| Sphaerobelum truncatum Wongthamwanich, in Wongthamwanich, Panha, Sierwald, Wesener et Thirakhupt, 2012.
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Abstract
As a first step towards an inventory of the giant pill-millipedes in Thailand, a new species of the genus Sphaerobelum Verhoeff, 1924, Sphaerobelum truncatum n. sp. is described from Nan Province, northern Thailand. A determination key is presented for all five known Sphaerobelum species. Clear morphological differences between S. truncatum n. sp. and the other four Sphaerobelum species were found on the anterior telopods. For the first time in Sphaerobelum, the partial mitochondrial COI gene was sequenced for S. truncatum n. sp. and compared with distance, maximum parsimony and maximum likelihood methods to those of species from other giant pill-millipede genera. Sphaerobelum truncatum n. sp. was found to differ from all other analyzed giant pill-millipedes, including species of Zephronia Gray, 1832, by 22–30%, including numerous amino acid changes, supporting the separate status of Sphaerobelum among other giant pill-millipede genera. Maximum likelihood and parsimony analyses support the placement of Sphaerobelum in the Zephroniidae. Figures of all relevant structures of Sphaerobelum truncatum n. sp. are provided to allow the use of these characters in future descriptions of species of the family Zephroniidae.
Key words: giant pill-millipede, new species, arthropod, taxonomy, Thailand
Taxonomy
Family Zephroniidae Gray, 1843
Subfamily Zephroniinae Gray, 1843
Tribe Zephroniini Jeekel, 2001
Comment. We follow Jeekel’s (2001) classification of Zephroniidae. No phylogenetic analysis of the family Zephroniidae was ever undertaken, so any subfamilial or tribal affiliations of Sphaerobelum would be premature.
Genus Sphaerobelum Verhoeff, 1924
Type species. Sphaerobelum clavigerum Verhoeff, 1924
Other species included. S. hirsutum Verhoeff, 1924; S. bicorne Attems, 1938; S. separatum Attems, 1953, S. truncatum n. sp.
Diagnosis. Males of Sphaerobelum species can be distinguished from all other giant pill-millipede genera in the world by the distally swollen process of the second joint of the posterior telopod.
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| Sphaerobelum truncatum n. sp., Digital photographs, A: paratype in habitat; B: paratype, living specimen volvated; C: paratype, ventral view, arrow points to locking carina of anal shield; D: eye field and Tömösváry organ. A-C: Photographs not to scale. Scale bars = 1 mm. |
Sphaerobelum truncatum Wongthamwanich, n. sp.
Etymology. The specific epithet is a Latin adjective, meaning terminating abruptly, and refers to the truncated
state of the lateral end of the third podomere on the anterior telopods (Fig. 11C).
Nattarin Wongthamwanich, Somsak Panha, Petra Sierwald, Thomas Wesener and Kumthorn Thirakhupt. 2012. A New Species of the Giant Pill-millipede Genus Sphaerobelum Verhoeff, 1924 from northern Thailand, with An Extensive Description and Molecular Characters (Diplopoda: Sphaerotheriida: Zephroniidae). Zootaxa. 3220; 29–43.
