Philip Myers' akodont ("Akodon philipmyersi") is a recently described species of grass mouse from Misiones Province, Argentina.
 Like other grass mice, A. philipmyersi is a small, non-descript, greyish-brown mouse with prominent ears.
 The species was recognized as distinct from other grass mice on the basis of unique features of karyology, genetic sequence, cranial measurements, and general morphology.
The blackish grass mouse ("Thaptomys nigrita") also formerly called the ebony akodont, is a rodent species from South America.
 It is found in Argentina, Brazil, Paraguay and Uruguay.
 It is the only species in the genus Thaptomys.
Akodon spegazzinii, also known as Spegazzini's akodont or Spegazzini's grass mouse, is a rodent in the genus "Akodon" found in northwestern Argentina.
 It occurs in grassland and forest at 400 to above sea level.
 After the species was first named in 1897, several other names were given to various populations now included in "A. spegazzinii".
 They are now all recognized as part of a single, widespread and variable species.
 "Akodon spegazzinii" is related to "Akodon boliviensis" and other members of the "A. boliviensis" species group.
 It reproduces year-round.
 Because it is widely distributed and common, "Akodon spegazzinii" is listed as "least concern" on the IUCN Red List.
The Tarija akodont ("Akodon pervalens"), or Tarija grass mouse, is a species in the family Cricetidae native to Bolivia, and possibly Argentina.
Akodon albiventer, also known as the white-bellied grass mouse or white-bellied akodont, is a species of rodent in the family Cricetidae.
 It is found in the Andean highlands from southeastern Peru to southwestern Bolivia, northwestern Argentina, and far northeastern Chile at elevations from 2400 m to over 5000 m.
Abrothrix jelskii, also known as Jelski's Altiplano Mouse, Jelski's Grass Mouse, or the Ornate Akodont, is a species of rodent in the genus "Abrothrix" of family Cricetidae.
 It is found in the altiplano habitat of the Andes from central Peru through Bolivia into northwestern Argentina.
 Populations classified under "A. jelskii" include more than one species.
Misiones (] , "Missions") is one of the 23 provinces of Argentina, located in the northeastern corner of the country in the Mesopotamia region.
 It is surrounded by Paraguay to the northwest, Brazil to the north, east and south, and Corrientes Province of Argentina to the southwest.
Akodon budini, also known as Budin's akodont or Budin's grass mouse, is a species of rodent in the family Cricetidae.
 It is found in the Andes of northwestern Argentina and adjacent Bolivia.
 The species is named after Emilio Budin, an Argentine specimen collector who worked with Oldfield Thomas.
Abrothrix hershkovitzi, also known as Hershkovitz's grass mouse or Hershkovitz's akodont, is a species of rodent in the genus "Abrothrix" of family Cricetidae.
 It is found only on some remote islands in southern Chile.
 It is named after American zoologist Philip Hershkovitz.
Abrothrix longipilis, also known as the long-haired grass mouse or long-haired akodont, is a species of rodent in the family Cricetidae.
 It is found in central and southern Argentina and Chile.
 The southern Chilean "Abrothrix sanborni" may not be distinct from this species.

Question: Philip Myers' akodont is a recently described species of grass mouse from one of 23 provinces of Argentina, located in the northeastern corner of the country in what region?
Answer: Mesopotamia region