Calomys_expulsus
Caatinga vesper mouse
Species of rodent
The caatinga vesper mouse (Calomys expulsus) (also known as the caatinga laucha[2] or rejected vesper mouse[1]) is a rodent species in the family Cricetidae from South America.[2] It is endemic to eastern Brazil, where it is found in open savanna (cerrado) and thorny scrub (caatinga) habitats.[1] Its karyotype has 2n = 66 and FN = 68. It was formerly synonymized with C. callosus, but the latter has 2n = 50 and FN = 66.[2] Karyologic analysis of C. expulsus has shown that the X chromosome is large and submetacentric while the Y chromosome is either acrocentric or submetacentric.[3] Predators include the barn owl .[4] Sexual dimorphism in shape and size occurs; the former is present mainly before the age of 20 days. Males are smaller before age 50 days and larger thereafter, which becomes less prominent after 200 days.[5]
