Shaw Mayer's water rat

{{Short description|Species of rodent}}

{{Speciesbox

| name = Shaw Mayer's water rat

| status = LC | status_system = IUCN3.1

| status_ref = {{Cite journal | author = Aplin, K. | author2 = Dickman, C. | author3 = Singadan, R. | author4 = Menzies, J. | author5 = Helgen, K. | author6 = Wright, D. | author7 = Allison, A. | name-list-style = amp | title = Baiyankamys shawmayeri | journal = The IUCN Red List of Threatened Species | volume = 2016 | page = e.T10314A115097322 | publisher = IUCN | date = 2016 | url = http://www.iucnredlist.org/details/10314/0 | doi = 10.2305/IUCN.UK.2016-3.RLTS.T10314A22410031.en | access-date = 13 December 2017| doi-access = free }}

| genus = Baiyankamys

| species = shawmayeri

| authority = Hinton, 1943

| synonyms = Hydromys shawmayeri

}}

Shaw Mayer's water rat (Baiyankamys shawmayeri) is a semiaquatic species of rodent in the family Muridae.

It is found in the mountains of Papua New Guinea.