Ruschi’s rat  (Abrawayaomys ruschii)

Classified as Least Concern (LC) on the IUCN Red List (1).

Discovered as recently as 1979, only a few specimens of the enigmatic Ruschi’s rat have ever been captured (3). The upperparts of this medium-sized rat are greyish-yellow, becoming darker on head, and fading to pale yellowish-white on the underparts (2) (3). The fur is composed of fine, soft hairs interspersed with long, thick, bristles, which are banded grey and black (4). The ears are large and mostly bare, while the tail is sparsely covered with short, inconspicuous bristles, except at the tip where they become dense and long, forming a pale tuft (2).

Although Ruschi’s rat has only been found at a small number of localities, these records indicate a wide distribution, ranging from the state of Espirito Santo, south along the east coast of Brazil to Santa Catarina, and west to Misiones province in Argentina (1).

Ruschi’s rat is found in the hugely biodiverse Atlantic Forest region, where it inhabits moist, tropical primary forest, secondary forest and stands of bamboo (1).

Owing to a lack of study, very little is known about the biology of Ruschi’s rat (1) (2) (4).

Although Ruschi’s rat was previously classified as Endangered on the 1996 IUCN Red List, because of more recent findings indicating a relatively large distribution, its status was revised to Least Concern in 2008. While the main threat to this species is habitat loss resulting from deforestation, it is believed that there are still large areas of forest cover capable of supporting populations, and therefore Rushi’s rat is unlikely to be undergoing a significant decline. Nevertheless without detailed surveys, the true status of this species remains unknown (1).

While there are currently no specific conservation measures for Ruschi’s rat, it is known to occur within a number of protected areas, including the Parque Rio Doce in Brazil, and the Iguazu National Park in Argentina (1).

To learn more about conservation measures being employed in the habitat of Ruschi’s rat, visit:

• Conservation International – Biodiversity Hotspots:
  www.biodiversityhotspots.org/xp/hotspots/atlantic_forest
• WWF:
  www.panda.org/about_wwf/where_we_work/ecoregions/atlantic_forests.cfm
• The Nature Conservancy:
  http://www.nature.org/wherewework/southamerica/brazil/work/art5080.html

• Atlantic Forest: a highly biodiverse region found along the east coast of South America, comprising several different vegetation types, including high-altitude grassland, and lowland and montane forest.
• Secondary forest: forest that has re-grown after a major disturbance, such as fire or timber harvest, but has not yet reached the mature state of primary forest.

1. IUCN Red List (October, 2008)
   http://www.iucnredlist.org
2. Bonvicino, C.R., Oliveira, J.A. and D’Andrea, P. S. (2008) Guia dos Roedores do Brasil, com chaves para gêneros baseadas em caracteres externos. Centro Pan-Americano de Febre Aftosa - OPAS/OMS, Rio de Janeiro.
3. Nowak, R.M. (1999) Walkers Mammals of the World. Sixth edition. The Johns Hopkins University Press, Baltimore and London.
4. Pereira, L.G., Geise, L., Cunha, A.A. and Cerqueira, R. (2008) Abrawayaomys ruschii Cunha & Cruz, 1979 (Rodentia, Cricetidae) no Estado do Rio de Janeiro, Brasil. Papéis Avulsos de Zoologia, 48: 33 - 40.