20.

Furtive Tuco-tuco

Ctenomys occultus

French: Tuco-tuco furtif / German: Heimliche Kammratte / Spanish: Tuco tuco furtivo

Taxonomy. Ctenomys occultus Thomas, 1920,

“Monteagudo, about 80 km. S.E. of Tucuman City,” San Miguel de Tucuman, Departamento Simoca, Tucuman, Argentina, 27°31’ §, 65°17° W, 296 m.

Based on biogeography, C. occultus belongs to the Chacoan group, but based on mtDNA, it belongs to tucumanusspecies group. Chromosomal complement is 2n = 20 and FN = 40, and sperm is simple asymmetric. Monotypic.

Distribution. N Argentina, known only from the Tucuman Province.

Descriptive notes. Head—body 138-151 mm. No specific data are available for body weight. The Furtive Tuco-tuco is small. Pelage is generally warm brown. Upper surfaces are glossy cinnamon-brown,slightly darkening on crown. Under surfaces are washed pale and drab, and chin and throat are even paler. Skull has small bullae and sharpedged ledges projecting over orbital fossae. Incisors are proodont.

Habitat. Dry Chaco region. The Furtive Tuco-tuco is common along roads in southern Tucuman Province.

Food and Feeding. There is no information available for this species.

Breeding. There is no information available for this species.

Activity patterns. There is no information available for this species.

Movements, Home range and Social organization. There is no information available for this species.

Status and Conservation. Classified as Endangered on The IUCN Red List. Extent of occurrence of the Furtive Tuco-tuco is less than 5000 km?, its distribution is severely fragmented, and there is continuing decline in extent and quality ofits habitat. Its original distribution is under severe pressure from habitat loss and degradation to agricultural expansion, mainly to sugar cane and soy. Most habitat loss has occurred in the past six years.

Bibliography. Bidau (2006, 2015), Contreras & Bidau (1999), Barquez et al. (1991), Medina et al. (2007), Ortells (1995), Parada et al. (2011), Reig & Kiblisky (1968), Rossi et al. (1995).