Phylogenetic and morphological discord indicates introgressive hybridisation in two genera of Australian millipedes (Diplopoda, Polydesmida, Paradoxosomatidae)

Discord between molecular and morphological datasets was observed in two pairs of species of Australian millipedes in the family Paradoxosomatidae using morphological and molecular phylogenetic analysis (mitochondrial COI rDNA and 16 rRNA, and nuclear 28S rRNA). Close to the presumed distributional boundary between Pogonosternumnigrovirgatum (Carl, 1912) and Pogonosternumjeekeli Decker, 2017, near Dargo in Central Gippsland, Victoria, Pogonosternum specimens were collected which are phylogenetically closer to P.jeekeli in COI and 16S sequences, but are morphologically closer to P.nigrovirgatum. At Mount Osmond, Adelaide, South Australia, eight morphologically typical Somethuscastaneus (Attems, 1944) specimens were collected are phylogenetically closer to S.castaneus in 28S genealogy, but three of the eight are closer to S.lancearius Jeekel, 2002 in COI genealogy. These two cases are discussed in terms of hybridisation, past introgressive hybridisation events and aberrant morphology.

Integrative taxonomy reveals a new genus and new species of Philosciidae (Crustacea: Isopoda: Oniscidea) from the Neotropical region

Although new methods and data are conquering space in the field of taxonomy, such as integrative taxonomy, most terrestrial isopod species are still described based only on morphology. Species of the genus Atlantoscia Ferrara and Taiti, 1981 were the first and are the unique terrestrial isopods from the Neotropics for which a molecular phylogeny was already conducted. Previous results indicated that this genus could be paraphyletic, and a more detailed analysis would be required. Our aim was to reconstruct the phylogeny of Atlantoscia using mitochondrial and nuclear markers and test its monophyly by integrating molecular and morphological data. We observed that, indeed, Atlantoscia is paraphyletic. Atlantoscia ituberasensis Campos-Filho, Lisboa and Araujo, 2013 and Atlantoscia rubromarginata Araujo and Leistikow, 1999 were placed in a new genus of terrestrial isopods, Paratlantoscia gen. nov., together with a new species described in the present study, Paratlantoscia robusta sp. nov. The new genus is defined by the presence of specialized respiratory areas in the pleopod exopods and its validity is highly corroborated by molecular analyses and by biogeographic information. This study highlights the importance of multiple and complementary perspectives as a way to improve the quality of species hypothesis and associated descriptions.

Phylogenetic analysis of the Australian trans-Bass Strait millipede genus Pogonosternum (Carl, 1912) (Diplopoda, Polydesmida, Paradoxosomatidae) indicates multiple glacial refugia in southeastern Australia

This study documents the first detailed phylogenetic analysis of an Australian paradoxosomatid millipede genus. Two mitochondrial genes (partial COI and 16S) as well as partial nuclear 28S rDNA were amplified and sequenced for 41 individuals of the southeastern Australian genus Pogonosternum Jeekel, 1965. The analysis indicates that five species groups of Pogonosternum occur across New South Wales, Victoria and Tasmania: Pogonosternumnigrovirgatum (Carl, 1912), Pogonosternumadrianae Jeekel, 1982, Pogonosternumlaetificum Jeekel, 1982 and two undescribed species. Pogonosternumconiferum (Jeekel, 1965) specimens cluster within Pogonosternumnigrovirgatum. Most of these five species groups exhibit a pattern of high intraspecific genetic variability and highly localized haplotypes, suggesting that they were confined to multiple Pleistocene refugia on the southeastern Australian mainland. The phylogenetic data also show that northwestern Tasmania was colonized by Pogonosternumnigrovirgatum, probably from central Victoria, and northeastern Tasmania by an as yet undescribed species from eastern Victoria.