Cinderella fat-tailed mouse opossum

{{Short description|Species of marsupial}}

{{Merge from|Argentine fat-tailed mouse opossum|discuss=Talk:Cinderella fat-tailed mouse opossum#Proposed merge of Argentine fat-tailed mouse opossum into Cinderella fat-tailed mouse opossum|date=April 2025}}

{{Speciesbox

| name = Cinderella fat-tailed mouse opossum

| image =

| status = LC

| status_system = IUCN3.1

| status_ref = {{cite iucn |author=Flores, D. |date=2016 |title=Thylamys cinderella |volume=2016 |page=e.T51343307A22173237 |doi=10.2305/IUCN.UK.2016-2.RLTS.T51343307A22173237.en |access-date=19 November 2021}}

| genus = Thylamys

| species = cinderella

| authority = Thomas, 1902

| synonyms =

| range_map = Cinderella Fat-tailed Mouse Opossum area.png

| range_map_caption = Cinderella fat-tailed mouse opossum range

}}

The Cinderella fat-tailed mouse opossum (Thylamys cinderella) is a species of opossum in the family Didelphidae.{{MSW3 Didelphimorphia | id = 10400162 | page = 17}} It is found in northern Argentina and southern Bolivia, in the eastern foothills of the Andes. Its dorsal fur is gray brown to dark brown. Its ventral fur is gray-based, except for the white to yellowish chest hairs. It has been distinguished from T. sponsorius by the well-developed postorbital ridges of the latter,{{Cite book | last = Gardner | first = Alfred L. | title = Mammals of South America: Marsupials, xenarthrans, shrews, and bats | publisher = University of Chicago Press | date = 2008 | pages = 669 | url = http://google.com/books?id=dbU3d7EUCm8C&pg=PA109 | isbn = 978-0-226-28240-4}} but mitochondrial DNA sequence analysis does not support separate species status for sponsorius.{{cite journal | author = Braun, J.K.| year = 2005 | title = Phylogenetic and biogeographic relationships of mouse opossums Thylamys (Didelphimorphia, Didelphidae) in southern South America | journal = Journal of Mammalogy | volume = 86 | issue = 1 | pages = 147–159 | doi = 10.1644/1545-1542(2005)086<0147:PABROM>2.0.CO;2|display-authors=etal| doi-access = free }}