Mesomys

Mesomys is a genus of South American spiny rats in the family Echimyidae.^[1]

Mesomys
Ferreira's spiny tree-rat
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Rodentia
Family:	Echimyidae
Subfamily:	Echimyinae
Tribe:	Echimyini
Genus:	Mesomys Wagner, 1845
Type species
Mesomys ecaudatus Wagner, 1845 (= Echimys hispidus Desmarest, 1817)
Species
Mesomys hispidus Mesomys leniceps Mesomys occultus Mesomys stimulax

The genus name Mesomys derives from the two ancient greek words μέσος (mésos), meaning "middle of, between", and μῦς (mûs), meaning "mouse, rat".^[2][3] It refers to the fact that these rodents — literally the "middle mouse" — were considered an intermediate form between the genus Loncheres and the genus Echinomys, both of which are now known to be synonyms of Echimys.^[4][5]

Extant species

Image	Scientific name	Common Name	Distribution
	Mesomys hispidus	Ferreira's spiny tree-rat	Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname and Venezuela
	Mesomys leniceps	Woolly-headed spiny tree-rat	Peru
	Mesomys occultus	Tufted-tailed spiny tree-rat	Brazil
	Mesomys stimulax	Pará spiny tree-rat	Brazil.

Phylogeny

Mesomys is a member of the Echimyini clade of arboreal Echimyidae rodents.^[6] The closest relative of Mesomys is Lonchothrix, reflecting the fact that these taxa have once been classified in the Eumysopinae,^[1] a subfamily now recognized as an artificial assemblage.^[7] These two genera share phylogenetic affinities with several taxa and clades: (i) Echimys, Phyllomys, Makalata, Pattonomys, and Toromys ; (ii) the bamboo rats Dactylomys, Olallamys, Kannabateomys together with Diplomys and Santamartamys ; and (iii) Isothrix.^[8]

Genus-level cladogram of the Echimyini.

Echimyini              Isothrix   "Eumysopines"     Lonchothrix   (Tuft-tailed spiny tree-rat)   Mesomys                                           Pattonomys   Toromys   (Giant tree-rat)             Makalata   Echimys   Phyllomys   Diplomys   Santamartamys   (Red-crested tree-rat)   "Dactylomyines"     Kannabateomys   (Atlantic bamboo rat)             Dactylomys   Olallamys

The cladogram has been reconstructed from mitochondrial and nuclear DNA characters.[9][10][11][12][7][13][14][15][6][8]