Chinchilla chinchilla (Lichtenstein, 1829)

Don E. Wilson, Thomas E. Lacher, Jr & Russell A. Mittermeier, 2016, Chinchillidae, Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I, Barcelona: Lynx Edicions, pp. 462-481 : 478-479

3.

Short-tailed Chinchilla

Chinchilla chinchilla

French: Chinchilla a queue courte / German: Kurzschwanz-Chinchilla / Spanish: Chinchilla de cola corta

Other common names: Highland Chinchilla

Taxonomy. Eriomys chinchilla Lichtenstein, 1830 ,

type locality not given. Identified by H. Prell in 1934 as “Peru.” In contrast, G.

M. Allen in 1942 stated that Lichtenstein (1830) “implied that the specimen came from Chile, not Peru.”

This species has been commonly referred to as C. brevicaudata , but H. Lichtenstein’s earlier name chinchilla has priority. Monotypic.

Distribution. N Chile, actual identified colonies are restricted to highlands of Antofagasta (23° S) to Atacama region (27° S). According to recent reports, relict populations may still persist in the border regions of Bolivia (Potosi) and Argentina (Jujuy, Catamarca, and Salta).

Descriptive notes. Head-body 300-380 mm,tail up to 100 mm, ear less than 32 mm, hindfoot ¢.120 mm; weight 500-850 g, males rarely weight more than 600 g. The Short-tailed Chinchilla is among the smallest chinchillid rodents; condylobasal length (most from Abra Pampa, Jujuy, Argentina) is 60-8 mm, greatest width of skull across zygomatic arches is 35-4 mm, interorbital width is 1-2 mm, mastoid width is 33-5 mm, and upper molar tooth row is 13-7 mm. Extremely dense silky pelage of long soft hair up to 35 mm is considered one of the most valuable furs in the world. General color of dorsum is bluish, pearl, or brownish gray, and each hair usually has a black tip. Venter is clear, yellowish white. Furry tail is covered with coarse hair on dorsal surface. Head is broad, with vestigial cheek pouches; pinnae are rounded, with a cover of tiny hair. Skull of the Short-tailed Chinchilla has greatly expanded auditory bullae, with mean bullar width of 13-1 mm, bullar height of 24-5 mm, and greatest width of skull across parietals including external bullae of 31-9 mm. Forefootis short, with five digits and stiff bristles surrounding weak claws. Hindfoot has one rudimentary and three normal digits. Relatively broad head has greatest width of skull across zygomatic arches (mean of head 36-5 mm, skull 34-2 mm). Mandible lacks a masseteric crest. Canal of large lacrimals opens on side of rostrum. Short paraoccipital processis attached to auditory bulla. As in the Chilean Chinchilla (C. lanigera ), each auditory bulla of the Short-tailed Chinchilla is extremely inflated, having three large vesicular protuberances. Dental formula of hypsodont teeth is I 1/1, C 0/0, P 1/1, M 3/3 (x2) = 20. Occlusal surface has three closely packed lamellar plates. Laminae of cheekteeth are widened and fused, with enamel of each crest strengthened on anterior side but weakened on posterior side in uppers, with reverse on lowers. Enamel of delicate incisors is usually dark yellow. Well-developed hindlimb is longer than forelimb. Means lengths of limb bones (in mm) are humerus, 35-5; radius, 39; ulna, 48-7; femur, 58-2; and tibia, 68-2. Vertebral formula is 7 cervical, 13 thoracic, 6 lumbar, 2 sacral, and 20 caudal (48 vertebrae). The Short-tailed Chinchilla has longer dorsal hair than the Chilean Chinchilla , up to 35 mm. Hair on dorsum are blue-gray at root, with a distal broad white tinge and dark gray at tip, producing a silvery gray tint suffused with black. Venter, inner surfaces of limbs, and feet are whitish. Tail has two dark bands on upper surface. Chromosome number is 64, with 128 chromosome arms. Molecular genetic distance (mtDNA sequences of cytochrome-b gene) between the Short-tailed Chinchilla and all species of Lagidium studied is rather large: 12:6% (12-13-6%).

Habitat. Associated with Adesmia horrida, A. caespitosa, A. erinacea ( Fabaceae ), Baccharis tola, B. incarum ( Asteraceae ), Chuquira gaulicina, Cristaria andicola ( Malvaceae ), Fabiana bryoides ( Solanaceae ), Parastrephia lepydophylla, P. quadrangularis ( Asteraceae ), and Stipa chrysophylla ( Poaceae ) in the Antofagasta region, Chile. Colonies of Short-tailed Chinchillas are sympatric with the Ashy Chinchilla Rat ( Abrocoma cinerea), Andean Soft-haired Mouse (Abrothrix andinus dolichonyx), Yellow-rumped Leaf-eared Mouse (Phyllotis xanthopygus), and the Guanaco (Lama guanicoe). Colonies in the Atacama region, Chile, used areas with streams and boulders and medium-sized caves, with sparse scrubby vegetation of Stipa frigida and Senecio volckmannii (both Asteraceae ). The Yellow-rumped Leaf-eared Mouse and Andean Soft-haired Mouse also occur in these areas. Remains of a jaw and feces were found at a northern site in Santa Rosa Lagoon in the northern area of Nevado Tres Cruces National Park. Principal predator identified at the three colonies studied was the Culpeo (Pseudalopex culpaeus).

Food and Feeding. The diet of the Short-tailed Chinchilla is known only from the Morro Negro site near the Llullaillaco Volcano, where it feeds mainly on S. chrysophylla (591% of diet) and secondarily consumes other plant such as A. erinacea, C. andicola, and other shrubs ( Solanaceae ) and herbs ( Malvaceae ).

Breeding. The Short-tailed Chinchilla produces 2-3 litters/year. In optimal conditions, wild females can produce a litter in October, January, and April. Gestation in Bolivia and north-western Argentina is ¢.128 days. The Short-tailed Chinchilla can be sexually mature as early as 5-5 months, but average is closer to ¢.8 months. Semi-precocial neonates weigh c.35 g, have open eyes,are fully furred, and are able to creep under their mother’s body for warmth while she dries them. Females have one pair of inguinal and two pairs of lateral thoracic mammae. Neonates can eat plant food, which creates a smooth transition during weaning at c.6 weeks. Experimental breeding in captivity is difficult, resulting in high percentages ofsterility. Some crosses between the Chilean Chinchilla and the Short-tailed Chinchilla have been produced during captive breeding.

Activity patterns. The Short-tailed Chinchilla is crepuscular and nocturnal, occasionally resting at the surface of rocks and basking in the sun for long periods during the day.

Movements, Home range and Social organization. Little is known about the ecology, population biology, home range, or movements of the Short-tailed Chinchilla . It lives in colonies of one territorial male and indeterminate numbers of females and juveniles, which usually are expulsed later by the male.

Status and Conservation. CITES Appendix I (wild populations). Classified as Critically Endangered on The IUCN Red List. Historically, the Short-tailed Chinchilla was distributed from southern Peru and south-western Bolivia, to north-western Argentina and northern Chile; however,it has been recorded only in Chile in the last 50 years. Based on the 1999 Priority Conservation Index of H. L. Cofré and P. A. Marquet, the Short-tailed Chinchilla was cataloged as endangered because it has a geographical distribution of 85,000 km? in two countries, with a local abundance of 63-1 ind/km?, and it is mentioned in otherlists “rare” or “undetermined or inadequately known.” There are still doubts in the literature about its distribution, given that it is now restricted to three known colonies. It is also classified as critically endangered by the Evolutionary Distinct & Globally Endangered Program of the Zoological Society of London. The Short-tailed Chinchilla was considered extinct in Peru and Bolivia, but today it is considered as critically endangered in Bolivia because it maystill be possible to find wild populations in the southern department of Potosi. In Argentina,it is listed as critically endangered. In Chile, the Short-tailed Chinchilla is now considered extinct in the Tarapaca region and endangered in the Antofagasta and Atacama regions.

Bibliography. Allen (1942), Anderson (1997), Bernal & Silva (2003), Bidlingmaier (1937), Brass (1911), Cabrera (1960, 1961), Cabrera & Yepes (1960), Chacédn (1892), Chebez & Oliveras (2008), Cofré & Marquet (1999), Cor tés et al. (2003), D'Elia & Ojeda (2008), Dennler (1939), Diaz & Ojeda (2000), Glade (1988), Grau (1986), Iriarte & Jaksic (1986), Jiménez (1996), Lagos et al. (2012), Miller et al. (1983), Munoz-Pedreros & Gil (2009), Ostojic et al. (2002), Parera (2002), Prell (1934), Redford & Eisenberg (1992), Spotorno & Patton (2015), Spotorno, Valladares et al. (2004), Spotorno, Zuleta et al. (1998), Tamayo & Frassinetti (1980), Tarifa (2009), Tirado et al. (2012), Valladares (2002), Valladares, Espinosa et al. (2012), Valladares, Zuleta & Spotorno (2014), Walle (1914), Waterhouse (1848), Woods & Kilpatrick (2005).

Figures

1. Plains Viscacha (Lagostomus maximus), 2. Chilean Chinchilla (Chinchilla lanigera), 3. Short-tailed Chinchilla (Chinchilla chinchilla), 4. Ecuadorean Mountain Viscacha (Lagidium ahuacaense), 5. Common Mountain Viscacha (Lagidium viscacia), 6. Wolffsohn’s Mountain Viscacha (Lagidium wolffsohni)

Distribution. N Chile, actual identified colonies are restricted to highlands of Antofagasta (23° S) to Atacama region (27° S). According to recent reports, relict populations may still persist in the border regions of Bolivia (Potosi) and Argentina (Jujuy, Catamarca, and Salta).