Macrobiotus olgae sp. nov.: a new urban, limno-terrestrial eutardigrade (Tardigrada, Macrobiotidae) from Argentina

The authors identified a new species of the genus Macrobiotus during a revision of the Rocha-Doma tardigrade collection (National University of La Pampa, Argentina). New specimens from resampling were obtained, so that the new species, Macrobiotus olgae sp. nov., is integratively described using phase contrast microscope (PCM) material for morphology and morphometry, scanning electron microscope (SEM) material for very fine morphology, and DNA analysis. The new species has a slightly wrinkled cuticle with cuticular pores of two types and sizes (rounded/oval, smaller, and lenticular, bigger), oral cavity armature of the hufelandi type, and egg of the persimilis type. It belongs to the persimilis morphogroup and differs from all the other members of that group and the other congeneric species, by a unique combination of morphological and morphometric characters, and is also well differentiated genetically from all the other sequenced species. The discovery of Macrobiotus olgae sp. nov. confirms the importance of scientific collections and enriches the knowledge, today still limited, of the tardigrade fauna of Argentina and the whole Neotropical Region.