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A new species of the genus Mesobiotus is described from the Republic of South Africa using a traditional morphological approach (light and scanning electron microscopy) combined with molecular analysis (18S rRNA, 28S rRNA, ITS-2 and COI markers). Mesobiotus anastasiae sp. nov. differs from all known Mesobiotus species by having a unique combination of characters of the adult animals and the eggs. Adults of the new species have an oral cavity armature without elongate teeth in the second band, while the processes of the egg chorion have a basal collar and distinct rows of large pores. An updated key to the species of the genus Mesobiotus, including 66 of 70 currently described species, is given. An aquatic mite species from the Lobohalacarus weberi complex (freshwater Halacaridae) co-occurs with M. anastasiae sp. nov., suggesting that the newly described tardigrade inhabits constantly wet moss cushion habitats.
In this paper a new tardigrade species, Macrobiotus azzunae sp. nov., from Tunisia, is described. An integrative taxonomic approach was applied by combining morphological, morphometric and molecular data. In particular, light and scanning electron microscopy observations, and four genetic markers, three nuclear (18S rRNA, 28S rRNA and ITS-2) and one mitochondrial (COI) were used. The analysis showed that M. azzunae sp. nov. belongs to the Macrobiotus hufelandi group and is most similar to Macrobiotus sandrae Bertolani & Rebecchi, 1993. It differs from M. sandrae by a more pronounced constriction of the first macroplacoid (hardly visible in M. sandrae) and for the eggshell shape, with thinner wires of the reticulum and meshes around the processes larger than the inter-process meshes in M. azzunae sp. nov., while all meshes are similar in size in M. sandrae. The species is gonochoristic. With this discovery, there are 33 species of tardigrades identified in Tunisia, all non-marine. This result, compared with nearby Sicily, where more research has been conducted, indicates that there is a considerable potential for identification of new species. Further research will be most informative if multiple habitats are explored and if carried out with an integrated approach as done in this present work.
In the present study, we used an integrative taxonomy approach to redescribe a population of Echiniscus quadrispinosus quadrispinosus Richters, 1902 from the neotype locality in the Taunus Mountain Range (Germany). We found clear differences in the chaetotaxy formula between the life stages of E. q. quadrispinosus. The body appendages B are, in general, absent in juveniles. Moreover, in larvae all body lateral appendages, except for E, are absent. We also obtained DNA sequences of 18S rRNA, 28S rRNA, ITS-2, and COI of E. q. quadrispinosus from the neotype locality and three Norwegian populations. Comparison with the sequences available in GenBank showed low genetic differences between the neotypic population and specimens from other localities. Therefore, we decided to establish our specimens from Taunus Mountain Range as neotype and paraneotypes of E. q. quadrispinosus. We also discussed and amended the taxonomic status of three subspecies E. q. brachyspinosus Bartoš, 1934, E. q. cribrosus Murray, 1907 and E. q. fissispinosus Murray, 1907 and established them as junior synonyms of E. q. quadrispinosus. Finally, we also confirmed E. lichenorum Maucci, 1983 as a valid species, clearly different from E. q. quadrispinosus.