Distribution extension and sympatric occurrence of Gracilinanus agilis and G. microtarsus (Didelphimorphia, Didelphidae), with cytogenetic notes

Abstract

Gracilinanus microtarsus, from the Atlantic Forest and G. agilis, widespread in central Brazil in the Cerrado and in the northeastern Caatinga are two small Neotropical arboreal opossum species not frequently recorded in simpatry. Here we report eight G. agilis specimens from three localities and 17 G. microtarsus, from 10 localities, all in Minas Gerais, Rio de Janeiro and Bahia states. Species proper identification followed diagnostic characters as appearance of dorsum pelage, ocular-mark, ears and tail lengths and size proportion of the posteromedial vacuities in cranium. Chromosomes in metaphases of five specimens were obtained for both species. Our records extend the previous known geographical distribution of G. microtarsus to Chapada Diamantina, in Bahia State and report the occurrence of both species in simpatry. G. microtarsus, in coastal area, was captured in dense ombrophilous and in semideciduous forests, in deciduous seasonal forest and Cerradão in Chapada Diamantina. G. agilis was recorded in gallery forests of Cerrado and very green and dense bush formation of Caatinga. Autosomal complement showed the same diploid and autosomal number already described for both species (2n = 14, NA = 24). Measurements are according to those given in literature and pelage characteristics were useful for the correct species identification. Here we report both G. agilis, described to be endemic to the Cerrado/Caatinga, in opposite to G. microtarsus, considered to be endemic to Atlantic Forest occurring in simpatry in two localities of the Cerrado. Such results indicates that long term trapping effort are necessary to a better definition of species taxonomy, distribution patterns along time and comprehensive understanding how anthropic environmental changes can be interfering in their evolutionary history.

Survey of Small Mammals (Rodentia and Didelphimorphia) in a Cerrado Reserve: Central Espinhaço Mountain Range, Brazil

“…A high but not significant correlation indicates a high probability of this correlation occurring by chance or being influenced by a small sample size. Bonvicino et al 2002, Geise & Astúa 2009, Pereira & Geise 2009, Paglia et al 2012, Nogueira et al 2015, Patton et al 2015. A similar pattern represented by species shared with Atlantic Forest, Caatinga and Cerrado was observed in other studies carried on the Espinhaço Range (see Pereira & Geise 2007, 2009, Câmara & Oliveira 2012, Braga et al 2016 which is a contact zone between the Cerrado and Atlantic Forest to the south and a transition zone between the Cerrado, Atlantic Forest and Caatinga in the northern (Giulietti et al 1997).…”

“…However, despite the limited information on the diversity of mammals across this Oecol. Aust., 21(2): 147-155, 2017 mosaic landscapes (Lessa et al 2008), recent researches revealed the occurrence of species considered to be restricted to the Atlantic Forest (Geise & Astúa 2009, Loss et al 2015 and even the description of a new genus of Sigmodontinae rodent (Pardiñas et al 2014). The Parque Estadual do Rio Preto (PERP), one of the few Cerrado protected areas in the Central Espinhaço, harbors a great diversity of small mammals (Lessa & Paula 2014) and was highlighted in 2005 as one of the 52 priority sites for mammal conservation in Minas Gerais state (Drumond et al 2005).…”

Conservation units in the core area of the Cerrado domain: an overview on the small nonvolant mammals (Rodentia and Didelphimorphia)

“…Gerais (Geise & Astúa, 2009), and Mato Grosso (Garcia et al, 2010). Cryptonanus agricolai specimen showed 2n = 14 and FNa = 24 ( Figure 3I), similar to the karyotype reported for this genus (Voss et al, 2005).…”

Small mammals in the diet of Barn Owls (Tyto furcata) in an urban area in Rio de Janeiro state, Brazil, with a new record of the dwarf mouse opossum (Cryptonanus)

“…The presence of H. brasiliensis and N. lasiurus among the food items thus suggests the owls are sporadically hunting in rural areas with abandoned or less managed pastures near the nesting site. Despite the noteworthy records of native species, most native small mammals found in nearby restingas and coastal forests (Geise and Astúa, 2009;Pessôa et al, 2010) and already documented in owl pellets (Lemos et al, 2015) were not present in the diet items analyzed herein. The diet sample of small mammals reported here is thus representative of an urban area with low species richness and high dominance of the invasive Mus musculus.…”