Asst. Prof. Dr Piyatida Pimvichai, Department of Biology, Faculty of Science, Mahasarakham University found a new genus of millipedes named Coxobolellus Pimvichai, Enghoff, Panha & Backeljau 2020, including 10 new species. The article was published in Invertebrate Systematics Journal on August 14, 2020, titled “Integrative taxonomy of the new millipede genus Coxobolellus, gen. nov. (Diplopoda : Spirobolida : Pseudospirobolellidae), with descriptions of ten new species.” 

The study 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. 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.

Live Coxobolellus, gen. nov. species from Thailand. A, C. albiceps, sp. nov. (from Tham Pha Tub), male (paratype, CUMZ-D00121-1). B, C. albiceps, sp. nov. (from ThamWang Daeng), male (paratype, CUMZ-D00124-1). C, C. albiceps, sp. nov. (from Tham Pha Tub), male (paratype, CUMZ-D00121-2). D, C. fuscus, sp. nov. (from Wat Tha Khanun), male (paratype, CUMZ-D00137-1). E, C. tenebris, sp. nov. (from Weluwan Khiriwong), male (paratype, CUMZ-D00138-1). F, C. tigris, sp. nov. (fromWat ThamKhao Plu), male(paratype, CUMZ-D00130-1).
Distribution of the species of Coxobolellus, gen. nov. in Thailand. Droplets vary in size only to improve readability.

The evolutionary relationship of this group of millipedes was also studied using biomolecular data. The discovery of these millipedes is fascinating. This is because in some species there are a variety of morphological variations. Thus, millipedes are considered an essential model that can apply in the educational of taxonomy and evolution.

Pimvichai, P., Enghoff, H., Panha, S. and Backeljau, T (2020). Integrative taxonomy of the new millipede genus Coxobolellus, gen. nov. (Diplopoda : Spirobolida : Pseudospirobolellidae), with descriptions of ten new species. Invertebrate Systematics, 34(6): 591-617. https://doi.org/10.1071/IS20031

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