An integrative description of Macrobiotus hannae sp. nov. (Tardigrada: Eutardigrada: Macrobiotidae: hufelandi group) from Poland

Abstract

A new species of the Macrobiotus hufelandi group is described from Poland. An integrative taxonomic approach was applied by combining morphological and morphometric analysis imaging under phase contrast and scanning electron microscopy with molecular analysis (four molecular markers) to unambiguously support the establishment of the new species. The specimens of Macrobiotus hannae sp. nov. are similar to three taxa of the Macrobiotus hufelandi complex: Macrobiotus hufelandi C.A.S. Schultze, 1834; M. punctillus Pilato, Binda & Azzaro, 1990; and M. joannae Pilato & Binda, 1983. Nevertheless, the new species differs from the first two species by the absence of cuticular bars under claws on legs I?III, better developed oral cavity armature (large, with all three bands of teeth always well visible), the presence of a subterminal constriction in the second macroplacoid, some fine peculiarities in egg ornamentation morphology, and differences in a number of morphometric characters. The new species is most similar to M. joannae but it can be distinguished from it by the presence of a much finer granulation on the dorsal and lateral cuticle of the body that, in contrast to M. joannae, is not visible in light microscopy. Our study suggests that European records of M. joannae are most likely invalid and they represent M. hannae or an unknown similar species.