Re-description of the genus Pseudobiotus (Eutardigrada, Hypsibiidae) and of the new type species Pseudobiotus kathmanae sp. n.

Re-examination of the lectotype of Macrobiotus augusti Murray, 1907 and the subsequent transfer of the species to Thulinia necessitated the designation of a new type species for the genus Pseudobiotus. We are describing Pseudobiotus kathmanae sp. n. as the proposed new type species since these were the original specimens used to describe the genus Pseudobiotus. The other two species are either very uncommon (P. matici) or described only from a very short description of other authors and without type material (P, megalonyx). The presence of about 30 peribuccal lamellae, the shape and size of the dorsal and ventral buccal apophyses (crests), and the Isohypsibius-type claw distinguish Pseudobiotus from other genera. Pseudobiotus kathmanae differs significantly from the other two species in the genus, P. matici (Pilato, 1971) and P. megalonyx (Thulin, 1928), in a number of characters. The new species differs from P. matici particularly in the claws; the external and internal claws of P. matici are markedly different in size and shape, whereas they are similar in P. kathmanae. The number of macroplacoids easily distinguishes P. megalonyx, which has only 2 macroplacoids (and the second is peculiarly the longest), from P, kathmanae, which has 3.