Guiara
Euryzygomatomys spinosus
- Least concern
- Card rarity: Common
- Mammals

Fischer's guiara, is a spiny rat species found in Argentina, Brazil and Paraguay. It is one of only two species in the genus Euryzygomatomys. Its karyotype has 2n=46 and FN=88.
Classification
- Class
- Mammalia
- Order
- Rodentia
- Family
- Echimyidae
- Genus
- Euryzygomatomys