Caatinga vesper mouse explained

The caatinga vesper mouse (Calomys expulsus) (also known as the caatinga laucha or rejected vesper mouse) is a rodent species in the family Cricetidae from South America. It is endemic to eastern Brazil, where it is found in open savanna (cerrado) and thorny scrub (caatinga) habitats. Its karyotype has 2n = 66 and FN = 68. It was formerly synonymized with C. callosus, but the latter has 2n = 50 and FN = 66. Karyologic analysis of C. expulsus has shown that the X chromosome is large and submetacentric while the Y chromosome is either acrocentric or submetacentric.^[1] Predators include the barn owl .^[2] 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.^[3]

Notes and References

1. Pereira. L. G.. Geise. L.. August 2007. Karyotype composition of some rodents and marsupials from Chapada Diamantina (Bahia, Brasil). Brazilian Journal of Biology. en. 67. 3. 509–518. 10.1590/S1519-69842007000300016. 18094834. 1519-6984. free.
2. Magrini. L.. Facure. K. G.. November 2008. Barn owl (Tyto alba) predation on small mammals and its role in the control of hantavirus natural reservoirs in a periurban area in southeastern Brazil. Brazilian Journal of Biology. 68. 4. 733–740. 10.1590/s1519-69842008000400007. 19197490. free.
3. Hingst-Zaher. Erika. Marcus. Leslie. Cerqueira. R.. 2000-06-25. Application of geometric morphometrics to the study of postnatal size and shape changes in the skull of Calomys expulsus. Hystrix: The Italian Journal of Mammalogy. english. 11. 1. 10.4404/hystrix-11.1-4139. 0394-1914.