Calomys Cerqueirai

''Calomys cerqueirai'' is a species of rodent in the genus ''Calomys'' from southeastern Brazil. Distinct from other ''Calomys'' in its karyotype and characters of the fur, it is known only from two places in Minas Gerais. The karyotype was first described in 1996 and the species was formally named in 2010.

Taxonomy

In 1996, Geise and coworkers described a new karyotypic variant of ''Calomys'' from Lagoa Santa, Minas Gerais with 36 chromosomes and a fundamental number of 66 autosomal arms ( 2n = 36, FNa = 66), and a 2007 genetic analysis confirmed that the new variant represents an evolutionary lineage separate from other ''Calomys'' species. In 2010, Bonvicino and others described another karyotypic variant from Capitão Andrade, also in Minas Gerais, with 2n = 38 and FNa = 66, and concluded that both karyotypic variants represented a single, previously undescribed species, which they named ''Calomys cerqueirai''. The specific name honors Brazilian mammalogist Rui Cerqueira. A single fusion or fission event is sufficient to derive one of the two karyotypes from the other.

According to evidence from the mitochondrial cytochrome ''b'' gene, ''Calomys cerqueirai'' is sister to a group of four other species within a clade of large-bodied ''Calomys''.

Description

''Calomys cerqueirai'' is a relatively small member of the Sigmodontinae, but is large for a ''Calomys''. The upperparts are yellowish brown, becoming lighter towards the sides; this coloration is sharply delineated from the whitish underparts. The external ears (pinnae) are small and rounded and have a patch of white hair behind them. The tail, which is dark above and white below, is relatively short. The feet are fairly long and narrow and are covered above by white hairs.Bonvicino et al., 2010, p. 28 In two specimens from Capitão Andrade, the head and body length is , the tail length is , the hindfoot length is , the ear length is , and the body mass is .Bonvicino et al., 2010, table 3

In the skull, the front region (rostrum) is short and the braincase is broadened. The incisive foramina are long, extending between the first molars. The palate itself is also long, extending beyond the third molars, and near the third molars is perforated by a pair of posterolateral palatal pits.Bonvicino et al., 2010, p. 29 The cutting faces of the upper incisors are inclined backwards (opisthodont). The upper third molars are reduced in size.Bonvicino et al., 2010, p. 30

It differs from other ''Calomys'' by its karyotype and by characters of the fur.Bonvicino et al., 2010, pp. 31–32

Ecology and behavior

The species is known from two localities in Minas Gerais, southeastern Brazil, near the border of the Atlantic Forest and Cerrado biomes.Bonvicino et al., 2010, p. 20 Both specimens from Capitão Andrade were caught in grass near a stream. The species is infected by species of '' Taenia'' and '' Hepsilon'' and unidentified nematodes.Bonvicino et al., 2010, p. 21

References

Literature cited

* Bonvicino, C.R., de Oliveira, J.A. and Gentile, R. 2010
A new species of ''Calomys'' (Rodentia: Sigmodontinae) from southeastern Brazil.
Zootaxa 2336:19–35.

{{Taxonbar, from=Q5023152

cerqueirai
Mammals of Brazil
Mammals described in 2010