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 designatio n of a new type species for the genus Pseudobiotus. We are describing Pseud obiotus kathmanae sp. n. as the proposed new type species since these were the original specimens used to describe the genus Pseudobiotus. The other t wo species are either very uncommon (P. matici) or described only from a ve ry short description of other authors and without type material (P, megalon yx). The presence of about 30 peribuccal lamellae, the shape and size of th e dorsal and ventral buccal apophyses (crests), and the Isohypsibius-type c law distinguish Pseudobiotus from other genera. Pseudobiotus kathmanae diff ers significantly from the other two species in the genus, P. matici (Pilat o, 1971) and P. megalonyx (Thulin, 1928), in a number of characters. The ne w species differs from P. matici particularly in the claws; the external an d internal claws of P. matici are markedly different in size and shape, whe reas they are similar in P. kathmanae. The number of macroplacoids easily d istinguishes P. megalonyx, which has only 2 macroplacoids (and the second i s peculiarly the longest), from P, kathmanae, which has 3.