516.

Fossorial Giant Rat

Gyldenstolpia fronto

French: Akodon du Chaco / German: Gyldenstolpe-Riesenratte / Spanish: Rata gigante fosora

Other common names: Fossorial Kunsia

Taxonomy. Scapteromys fronto Winge, 1887, Pleistocene cave deposits (Lapa da Escrivania No. 5) near Lagoa Santa, Rio das Velhas, Minas Gerais, Brazil.

Gyldenstolpia fronto is the type species of the genus. Two subspecies were recognized based on subtle cranial and dental characteristics. Nominate subspecies fronto is known from only four fossils of Quaternary age recovered in two caves from the [Lagoa Santa area, Lapa da Escrivania Nr.

5, the type locality, and Lapa da Serra das Abelhas. The holotype and unique specimen of the subspecies chacoensis was collected in 1896, and there have been no new records since then. Monotypic.

Distribution. N Argentina, known only from a single locality in the NE Chaco Province.

Descriptive notes. Head-body 225 mm, tail 110 mm, ear c.20 mm (measured from dry skin), hindfoot 43 mm (measured from dry skin). No specific data are available for body weight. The Fossorial Giant Rat is large and probably heavy (c.150 g), with proportionately short tail. Pelage is coarse but not harsh, tawny mixed with dark brown on upperparts, covered with basally slaty-colored hairs, annulated buffy subterminally, and blackish tips; ears, muzzle and upperparts of forefeet and hindfeet are brown with a light buffy mixture; underparts are moderately well-defined from sides and are whitish or pale gray, lightly washed with buffy or yellowish and dark basal portions of hairs show through; and rhinarium is bordered with brown. Tail is ¢.50% orless of head— body length; its hairs are hispid, brown above, paler beneath, and shorter distally than proximally, with three hairs on each scale; keel hairs and pencil are absent; and scales are moderately enlarged and show through. Hindfootis stout and moderately long.

Habitat. Chacoan environment in and near freshwater.

Food and Feeding. No information.

Breeding. No information.

Activity patterns. No information.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Endangered on The IUCN Red List (as Kunsia fronto). Not recorded since 1896, it is highly likely that the Fossorial Gian Rat is now extinct.

Bibliography. Gyldenstolpe (1932a, 1932b), Hershkovitz (1966a), Pardinas & Bezerra (2015), Pardinas, D'Elia & Teta (2009), Pardinas, D'Elia, Teta & Patterson (2008), Reig (1972), Winge (1887).