Integrative taxonomy of the new millipede genus Coxobolellus, gen. nov. (Diplopoda : Spirobolida : Pseudospirobolellidae), with descriptions of ten new species

Publication Type:Journal Article
Year of Publication:2020
Authors:P. Pimvichai, Enghoff, H., Panha, S., Backeljau, T.
Journal:Invertebrate Systematics
Volume:34
Issue:6
Pagination:591-617
Date Published:14/08/2020
ISSN:1445-5226
Keywords:mitochondrial DNA, new genus, phylogeny, species delineation
Abstract:

Pseudospirobolellidae is a poorly known family of spirobolidan millipedes with only two genera and five described species. Yet, the descriptive taxonomy and molecular systematics of this group have been largely neglected. Therefore, the present work presents an integrative taxonomic study of new pseudospirobolellid taxa in Thailand. To this end, two mitochondrial gene fragments (COI and 16S rRNA) combined with morphological characters were used to define the genus Coxobolellus, gen. nov. with 10 new species, viz. C. albiceps, sp. nov., C. compactogonus, sp. nov., C. fuscus, sp. nov., C. nodosus, sp. nov., C. serratus, sp. nov., C. simplex, sp. nov., C. tenebris, sp. nov., C. tigris, sp. nov., C. transversalis, sp. nov. and C. valvatus, sp. nov. The interspecific COI sequence divergences among the new species ranged from 6 to 15%. The intergeneric COI sequence divergence between species of Coxobolellus, gen. nov., Benoitolus birgitae and Pseudospirobolellus sp. ranged from 20 to 23%. Three major morphological differences separate Coxobolellus, gen. nov. from Benoitolus and Pseudospirobolellus, namely (1) the protruding process on the 3rd (and 4th) coxae on male legs, (2) the posterior gonopod telopodite divided into two parts, and (3) a conspicuous opening pore at the mesal margin at the end of the coxal part of the posterior gonopod. Thus, the new genus is well supported by both mtDNA and morphological evidence, while the delimitation of the 10 new species is supported by the congruence between mtDNA and morphological data. Yet, with respect to the relationships of Benoitolus birgitae, morphological data suggest a similarity with Coxobolellus, gen. nov. and Pseudospirobolellus, whereas mtDNA data place this species in the Pachybolidae. Further phylogenetic analyses are needed to explore this apparent incongruence and test the monophyly of Pseudospirobolellidae.

URL:https://www.publish.csiro.au/is/IS20031
DOI:10.1071/IS20031
Short Title:Invert. Systematics
Citation Key:852
Refereed Designation:Refereed
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