Description of Milnesium pentapapillatum sp. nov., with an amendment of the diagnosis of the order Apochela and abolition of the class Apotardigrada (Tardigrada)

Tardigrades constitute a phylum of cosmopolitan, microscopic invertebrates, capable of withstanding harsh environmental conditions thanks to cryptobiosis. These tiny animals are taxonomically challenging due to the limited number of meaningful morphological traits and morphological stasis. One of the most extreme examples is the order Apochela, in which the morphology is even more simplified and conserved than in the majority of other...