Mayermys germani German's one-toothed moss mouse (Pseudohydromys germani)[1] is a species of rodent in the family Muridae which occurs in the mountains of southeastern New Guinea.

It was first described in the genus Mayermys, but this genus, which only included the two one-molared species, has since been synonymised under Pseudohydromys because of the close morphological resemblances among Mayermys and the other species now placed in Pseudohydromys.

As a member of the Xeromys division within the subfamily Murinae, P. germani is related to the false water rat (Xeromys myoides) of Australia and southern New Guinea and to the three species of Leptomys, another New Guinean genus, and more distantly to other New Guinean and Australian rodents, including the water rat.

It is known from only one specimen, an adult male which was caught at an altitude of 1300 m in the village of Munimun, Milne Bay Province, southeastern Papua New Guinea in August 1992.

P. germani was first described in 2005 by biologist Kristofer Helgen and named after Pavel German, who caught the specimen.