New Thai giant pill-millipede species

Three new species of giant pill-millipedes, Sphaerobelum meridionalis Bhansali & Wesener sp. nov., Zephronia chrysomallos Bhansali & Wesener sp. nov. and Zephronia erawani Bhansali & Wesener sp. nov. are described based on museum samples from Thailand. All three species are described in an integrative manner, combining light microscopy, scanning electron microscopy, CT scans and genetic barcoding. Genetic barcoding was successfully conducted for all holotypes of the new species. In addition, genetic barcoding data of four recently described Thai Zephronia species, Zephronia lannaensis Likhitrakarn & Golovatch, 2021 in Likhitrakarn et al. 2021, Z. phrain Likhitrakarn & Golovatch, 2021, Z. panhai Srisonchai et al. 2021 and Z. golovatchi Srisonchai et al. 2021, together with new locality records, were added to the dataset. Our dataset includes all published sequences of the family Zephroniidae, including all but one (Z. enghoffi Srisonchai et al., 2021) of the described species from Thailand, Laos and Cambodia. All new species are genetically distant from other Zephroniidae from Thailand and surrounding countries showing uncorrected p-distances of >10 %. S. meridionalis sp. nov. is genetically and morphologically close to a recently described aberrant Sphaerobelum, S. aesculus Rosenmejer & Wesener, 2021, as well as an unspecified specimen from Malaysia, and might represent a genus different from Sphaerobelum Verhoeff, 1924. Both new Zephronia species are geographically, morphologically and genetically close to Z. panhai, but differ from the latter by >10% p-distance in the COI gene and numerous morphological characters. Virtual cybertypes of the holotype of Zephronia erawani sp. nov. and of a paratype of Z. chrysomallos sp. nov. were created and made publicly accessible.