Pipanacoctomys aureus, Mares, Braun, Barquez & Diaz, 2000

Don E. Wilson, Thomas E. Lacher, Jr & Russell A. Mittermeier, 2016, Octodontidae, Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I, Barcelona: Lynx Edicions, pp. 536-541 : 538-539

3.

Golden Viscacha Rat

Pipanacoctomys aureus

French: Octodon doré / German: Goldene Viscacharatte / Spanish: Rata vizcacha dorada

Taxonomy. Pipanacoctomys aureus Mares et al., 2000 ,

“28 km S, 9-3 km W Andalgala; Departamento Poman, Catamarca Province, Argentina, 27° 50’ 03” 8° 66’ 15” 59” W; elevation 680 m,” Salar de Pipanaco, Saujil Department .

R. M. Barquez and colleagues in 2002 treated it as Tympanoctomys based on morphological characteristics, howeverit lacks of a formal description. C. A. Woods and C. W. Kilpatrick in 2005 and M. H. Gallardo and colleagues in 2007 have continued to recognize Pipanacoctomys as a valid genus. This last revision has been followed here. Morphological data suggest a sister taxon relationship with Salinoctomys and very close relationship with Tympanoctomys . Monotypic.

Distribution. NW Argentina , known only from the type locality in the Salar de Pipanaco, S Catamarca Province.

Descriptive notes. Head—body 166-178 mm,tail 127-145 mm, ear 19-22 mm, hindfoot 32-40 mm. The Golden Viscacha Rat is medium-sized to large-sized. It has large and inflated auditory bullae. Dorsal pelage is golden blond, and venteris white to pale cream. Tail is long (76-85% ofits head-body length), with well-developed terminal rufous brush. Whitish hairs cover forefeet and hindfeet. Buccal bristles are present but not as developed as in the Red Viscacha Rat ( 7. barrerae ). The Golden Viscacha Rat has a karyotype of 2n = 92, with 44-45 pairs of biarmed chromosomes and a biarmed X-chromosome and uniarmed Y-chromosome.

Habitat. Edge ofsalt pans associated with peri-saline shrublands of Heterostachys sp. , Atriplex lampa, and Suaeda divaricata (all Amaranthaceae ). The Golden Viscacha Rat lives in a restricted, narrow band of halophytic plants that lays between bare salt flats and more typical Monte Desert habitats of Prosopis (Fabaceae) , Larrea (Zygophyllaceae) , and other shrubs of the Monte. Complex burrow systems are shallow and have several openings.

Food and Feeding. The Golden Viscacha Rat is herbivorous and specializes on halophytic plants. It forages on Heterostachysritteriana, which has compressed leaves that form small , salt-filled balls. High salt content of these leaves cannot be reduced via mechanical means (as can leaves of Atriplex ) and buccal brushes of Pipanacoctomys seem to be less well developed than those of Tympanoctomys .

Breeding. Birth of a Golden Viscacha Rat was observed in October. Newborn was well haired, and eyes and ears were open within a few hours after birth.

Activity patterns. There is no specific information for this species, but the Golden Viscacha Rat is considered to be nocturnal.

Movements, Home range and Social organization. The Golden Viscacha Ratis ground dwelling, and apparently more than one individual can inhabit a single mound—different from the Red Viscacha Rat.

Status and Conservation. Classified as Critically Endangered on The IUCN Red List. Extent of occurrence of the Golden Viscacha Rat is less than 100 km?, and its area of occupancy is less than 10 km®. All individuals occurin a single location, and extent and quality of habitat continues to decline there. Major threat to the Golden Viscacha Rat is loss of habitat to expanding olive plantations.

Bibliography. Barquez et al. (2002), Gallardo et al. (2007), Mares, Braun et al. (2000), Mares, Morello & Goldstein (1985), Ojeda & Bidau (2013g), Woods & Kilpatrick (2005).

Figures

On following pages: 4. Chalchalero Viscacha Rat (Salinoctomys loschalchalerosorum); 5. Common Viscacha Rat (Octomys mimax); 6. Mountain Degu (Octodontomys gliroides); 7. Bridges's Degu (Octodon bridgesii); 8. Pacific Degu (Octodon pacificus); 9. Coastal Degu (Octodon lunatus); 10. Common Degu (Octodon degus); 11. Porter's Rock Rat (Aconaemys porteri); 12. Chilean Rock Rat (Aconaemys fuscus); 13. Sage’s Rock Rat (Aconaemys sage), 14. Coruro (Spalacopus cyanus).

Distribution. NW Argentina , known only from the type locality in the Salar de Pipanaco, S Catamarca Province.