HMW 6 – Species accounts: Plains Viscacha (Lagostomus maximus)

Subfamily LAGOSTOMINAE

Genus LAGOSTOMUS
Brookes, 1828

1. Plains Viscacha Lagostomus maximus

French: Viscache des plaines / German: Viscacha / Spanish: Vizcacha de llanura

Other common names: Argentine Plains Viscacha

Taxonomy. Dipus maximus Desmarest, 1817, type locality not given. Restricted by A. Cabrera in 1961 to southern Corrientes Province, Argentina.

Three subspecies recognized.

Subspecies and Distribution.

L. m. maximus Desmarest, 1817 – C Argentina.

L. m. inmollis Thomas, 1910 – SE Bolivia, S & W Paraguay, and NC Argentina.

L. m. petilidens Hollister, 1914 – S Argentina (S Buenos Aires, La Pampa, and Río Negro provinces).

Descriptive notes. Head–body 531–615 mm (males) and 395–562 mm (females), tail 154–205 mm (males) and 135–173 mm (females; measurements to tip of longest hair on tail), ear 50–65 mm (males) and 52–59 mm (females), hindfoot 118–136 mm (males) and 104–118 mm (females); weight 5–8·8 kg (males) and 3·5–5 kg (females). Mean weights of adult Plains Viscachas in semiarid grasslands of San Luis Province, Argentina, are lower: 5·9 kg (males) and 3·4 kg (females). The Plains Viscacha looks like an enormous chinchilla with a massive head, males in particular. It is among the most sexually dimorphic rodents. Head is remarkable by its rather large eyes, dark and coarse vibrissae (absent in females), and external nasal folds (to prevent earth entering nostrils). Both sexes have striking white markings on cheeks (more contrasted in males), above eyes, and at bases of moderately furred ears. Furred tail is short, proportionally much shorter than on other chinchillids. Hair is longest dorsally. Hindfeet are long and well developed, having three fingers with strong claws (digits one and five are missing); forefeet are shorter, with four long fingers with small thick claws for digging; specialized humeri also reflect digging ability. Front fingers have small terminal toe pads and strong hairs like combs. General color varies from silver-gray to brown-gray, with some sky-blue, and is darker on dorsum and whitish on venter and inside legs. Skull of the Plains Viscacha is flat, with broad frontals that bear triangular-shaped postorbital processes and heavy parasagittal ridging for muscle attachment. Rostrum appears robust, but nasals are relatively long and narrow. Jugal is deep and thick, extending upward to meet expanded lacrimal, and has moderately developed post-orbital process. Floor of large infraorbital foramen has deep groove bordered by lateral flange for nerve passage. Tympanic portion of bulla is expanded ventrally; mastoid portion is not inflated and, while visible when viewed from behind, is not visible on dorsal surface of cranium. Paroccipital processes are long, vertical, and extend well below and free from contact with small bullae. Incisive foramina are short, occupying less than one-half the length of diastema. Palate is strongly constricted anteriorly. Dental formula of the Plains Viscacha is I 1/1, C 0/0, P 1/1, M 3/3 (×2) = 20, with constantly growing teeth. Upper incisors are distinctly proodont, with weakly pigmented enamel, and are covered with faint longitudinal grooves. Each maxillary cheek tooth has only two straight and rather thick laminae, except M3 that has three, with the last plate essentially lacking a posteriorly directed heel. All mandibular teeth have two laminae. Mandible is thick and stout, with a reduced angular process that flares laterally, a low but conspicuous coronoid process, and well-developed ridge lateral to condyle for attachment of posterior masseter muscle. Chromosome number is 56, with 110 chromosomal arms. Molecular genetic distance (mtDNA sequences of cytochrome-b gene) between the Plains Viscacha and all species of Chinchillinae is very large at 18·2% (16·2–19·7%).

Habitat. Lowland habitats of dry thornscrub in Bolivia, Paraguay, and north-central Argentina; subtropical, humid grasslands in north-eastern Argentina; semiarid grasslands of central Argentina; and desert scrub in its south-western distribution. Annual precipitation in habitats occupied by Plains Viscachas varies from more than 1000 mm in north-eastern Argentina to less than 300 mm in west-central Argentina; predictability also varies annually.

Food and Feeding. The Plains Viscacha is strictly herbivorous; it eats a wide variety of plant species, mainly grasses in central Argentina, but also 27 herbaceous species, eleven shrub species, and occasionally seeds, fruits, and barks in dry scrub habitats. By intense and selective grazing and clipping, Plains Viscachas alter species composition, cover, and vegetation structure around their burrows, called vizcacheras, usually increasing amount of bare ground. Groups of up to 30 individuals may forage together. Adult males forage with females and young in winter but alone during the rest of the year. Between foraging bouts, individuals return to their natal vizcachera. On nights with no wind, feeding may last until after sunrise. Individuals spend more time feeding and less time at vizcacheras in winter than in other seasons, reversing the pattern in other seasons. Female Plains Viscachas nurse young inside vizcacheras for 2–3 months in spring, spending large amounts of time between foraging bouts during summer. Coprophagy has been observed.

Breeding. The Plains Viscacha reproduces seasonally, with most females breeding in austral autumn and young born in spring. Females have a vaginal closure membrane and a copulatory plug. Estrous cycle lasts c.40 days, hyper-ovulating 200–800 ova, followed by delayed implantation of up to five blastocysts in each uterine horn. Gestation is c.154 days, and young at birth are large and precocial. Average litter size is c.1·9 young. Lactation from two lateral pairs of thoracic mammae lasts 2–3 months. Females first conceive at a mean age of 214 days and give birth at c.368 days. Males reach sexual maturity at 12–16 months and exhibit a well-defined seasonal reproductive cycle. Testicular and epididymal masses and serum testosterone peak during mating in autumn when 91% of males are fertile. Males have a filiform penis and no sacculus urethralis—a trait that is unique among hystricomorph rodents. Gonadal activity decreases in winter. Longevity is estimated at 7–8 years.

Activity patterns. The Plains Viscacha is nocturnal and active throughout the year, emerging from burrows shortly before dusk. Groups of up to 30 individuals forage together. Adult males forage with females and young in winter but alone during the rest of the year. Seasonal changes in activity budgets of males are associated with increases in conflicts among males, vigilance for intruding males, and territorial displays. Females remain their natal home ranges, but males typically disperse although they may continue to reside in their natal home ranges when environmental conditions are poor. Groups frequently coalesce and change membership during the night. Complete turnover of adult males is typical every year, with resident males replaced by immigrants from other colonies. Residents repeatedly chase intruders. Fights occur occasionally, with bipedal wrestling, biting of hindquarters and throat, rolling, and kicking. Aggression among neighbors is rare. Grooming was observed among all sex and age classes within a group and consisted of nibbling on face, neck, and back and rubbing cheeks. Mutual grooming is common. Plains Viscachas—most frequently adult males—emit loud, two-syllable “pi-chung,” anti-predator calls, which are interspersed with whinnies, grunts, squeaks, and foot stamping. These calls are similar to those used in response to male intruders. During aggressive encounters, tail is arched, and hairs are erected. Adult Plains Viscachas collect bones, stones, and sticks and pile them at entrances of vizcacheras. Adult males urinate on sticks and rub their cheeks on them; females do not show these behaviors. Tail is used as a third leg when an individual sits on its haunches. Plains Viscachas dig with their forefeet, and soil is pushed out with the nose or kicked backward by hindlegs.

Movements, Home range and Social organization. The Plains Viscacha is colonial and builds a communal vizcachera, where 1–3 adult males, 2–4 times as many females, and young live together throughout the year. Number of burrows is 18–93, with satellite burrows scattered among them. Satellite burrows are seldom used except to escape high-risk situations in winter; they serve as residences and display sites for adult males during the breeding season from spring to autumn. An individual Plains Viscacha generally enters its own vizcachera rather than a satellite or another principal vizcachera, unless there is extreme danger. All individuals from a single vizcachera share a common home range, averaging 1·3 ha in central Argentina, with a minimal overlap between adjacent vizcacheras. Principal vizcacheras and their associated satellites are aggregated in patches called “vizcacherales.” Individuals may forage at considerable distances beyond boundaries of home ranges. A. C. Llanos and J. A. Crespo in 1952 reported that Plains Viscachas forage up to 400 m from their vizcacheras. Boundaries are not defended, but all members of a group will defend their vizcacheras from intruders of either sex or age class. They also have frequent cooperative behaviors such as grooming and anti-predator calls. A call may be repeated continually for several minutes, is contagious among males at neighboring vizcacheras, and results in a general run to their home burrow. The Plains Viscacha is a good and speedy runner (up to 40 km/h) and can jump up to 3 m. When startled by a minor threat, adult females and occasionally juveniles give a single syllable “wank.” A group responds by looking around but does not run for cover. When under severe stress, individuals emit a “scream” that results in conspecifics running to that individual. Members of a group have access to all burrows in vizcacheras, and all members use a communal dust bath. There are no clear dominance hierarchies among males or females. Two or more resident adult males often sit in close proximity to each other near a burrow entrance, occupy the same underground chamber even during the mating season, and forage together. Males disperse, but when environmental conditions are poor, they may remain in their natal vizcachera up to 27 months. During a population decline in semiarid scrub in La Pampa Province, adult females and juveniles abandoned their resident vizcachera when number of individuals became very low and moved as a group to the closest vizcachera. Predators of Plains Viscachas include the Puma (Puma concolor), Geoffroy’s Cat (Leopardus geoffroyi), the Crab-eating Fox (Cerdocyon thous), the Pampas Fox (Lycalopex gymnocercus), the Lesser Grison (Galictis cuja), the great horned owl (Bubo virginianus), the crowned solitary eagle (Harpyhaliaetus coronatus), and the boa constrictor (Boa constrictor).

Status and Conservation. Classified as Least Concern on The IUCN Red List. With increases in cattle grazing, overall distribution of the Plains Viscacha has increased, although many local populations have been eliminated because they damage pastures and provide meat and pelts to local farmers and hunters. More than 370,000 skins of Plains Viscachas were exported in 1976–1979 through Buenos Aires, Argentina.

Bibliography. Barquez et al. (2006), Branch (1993a, 1993b, 1993c), Branch et al. (1993, 1994), Cabrera (1961), Cabrera & Yepes (1960), Canevari & Vaccaro (2007), Diaz & Ojeda (2000), George & Weir (1974), Jackson et al. (1996), Llanos & Crespo (1952), Morgan & Álvarez (2013), Muñoz-Pedreros & Gil (2009), Parera (2002), Redford & Eisenberg (1992), Spotorno & Patton (2015), Spotorno et al. (2004), Walker (1968), Weir (1974), Wiegmann (1835), Woods & Kilpatrick (2005).

 

Subfamily CHINCHILLINAE

Genus CHINCHILLA
Bennett, 1829

2. Chilean Chinchilla Chinchilla lanigera

French: Chinchilla à longue queue / German: Langschwanz-Chinchilla / Spanish: Chinchilla de cola larga

Other common names: Coastal Chinchilla, Common Chinchilla, Long-tailed Chinchilla

Taxonomy. Chinchilla lanigera Bennett, 1829, “Coquimbo, Chile.”

This species is monotypic.

Distribution. N Chile (Coquimbo and Atacama regions), extant wild populations are restricted to Las Chinchillas National Reserve, 24 km N Aucó, and surrounding areas (Quebrada Curico and Quebrada El Cuyano), and the new colony recently reported in La Higuera, c.100 km N Coquimbo; it was also reported in the Atacama region during the first part of the 20th century, particularly around Vallenar.

Descriptive notes. Head–body 220–240 mm, tail 140–170 mm, ear 45–48 mm, hindfoot 54–58 mm; weight 369–493 g (wild males), c.600 g (domestic males), 379–450 g (wild females), and c.800 g (domestic females). Chilean Chinchillas have round and long ears (more than 45 mm), covered by tiny hair, and long tails (more than 130 mm). Hair is 20–40 mm long, with gray, white, and black bands; it is silky, extremely soft, and firmly adhered to skin; thus, it is commercially valuable. Fifty to 75 hairs emerge from a single skin pore. Wool hairs (5–11 mm in diameter) are grouped in two lateral clusters. A single guard hair (10–15 mm in diameter) is located at the center of each cluster. Vibrissae are abundant, strong, and long (100–130 mm) and emerge from single follicles. Each group of hairs has one erector pili muscle. Guard hairs have their own sebaceous glands, whereas 3–4 other glands serve all hairs of a lateral group. Solitary hairs are found as vibrissae or on the tail as pinnae. Follicular layering is found only in vibrissae. Color of upper parts is bluish or silver gray, and under parts are yellowish white. Tail has long, coarse, gray and black hair on its dorsal surface; they are 30–40 mm near body, 50–60 mm near tail tip, and form a bristly tuft of 50 mm. Skull of the Chilean Chinchilla has very expanded auditory bullae that protrude over upper plane; it is relatively broad, with little or no ridging. Infraorbital canal is very large, without a distinct groove for nerve passage. Lacrimal canal has a large opening on rostrum side. Paroccipital process is short and attached to bulla. Jugal approaches lacrimal. Pituitary is 3·5 mg/100 g of body weight in males and 4 mg/100 g in females. Auditory bullae have three large vesicular protuberances; superior protuberance is nearly hemispherical, posterior is oblong, and inferior is pyriform. Mean total volume of middle ear is 1·5 ml. Tympanic membrane is nearly parallel to medial wall of external meatus and anchored to bony annulus; tympanic flat area is 55·6 mm2, but when its conical form is considered, average area increases 9% to a mean of 60·4 mm2. Forelimbs are much smaller in size than hindlimbs. Tibia is longer than femur, and fibula is virtually nonexistent. Short forefeet have five digits, and narrow hindfeet have three digits and a rudimentary digit with stiff bristles surrounding a small, flat claw. Other claws present but very short. Females have two pairs of thoracic and one pair of inguinal mammae, although the latter are not visible in wild females. Area around mammae is devoid of hair during lactation. Teeth are hypsodont and ever growing (rootless). Upper tooth rows are convergent anteriorly and crowns of cheekteeth are flat, consisting of a series of transverse plates. Dental formula of the Chilean Chinchilla is I 1/1, C 0/0, P 1/1, M 3/3 (×2) = 20. Incisors grow 50–75 mm/year. Enamel is usually dark yellow in healthy individuals; some inner radial enamel occurs close to dentin-enamel junction and in portio externa. Lower jaw has no ridge or groove on lateral surface; angular process is elongated and not deflected. Condyle is small and longitudinal, and glenoid cavity is superficial, permitting motion in anterior-posterior direction. Vertebral formula is 7 cervical, 13 thoracic, 6 lumbar, 2 sacral, and 23 caudal (51 vertebrae), with 13 pair of ribs. Radius and ulna, although distinct, are so closely applied to each other at their carpal extremity that they appear anchylosed for one-half of their length. Interarticular cartilage between clavicle and sternum is c.6 mm. Masseter is divided in three portions. Gluteus medius is enlarged. Temporalis is reduced and undifferentiated. Internal carotid artery is absent, and brain is supplied by vertebral-basilar artery system alone, whereas external carotid artery system has assumed entire stapedial area of supply by means of three anastomoses; internal ophthalmic artery is closed. Arterial irrigation of testicles and epididymis proceeds from testicular arteries that emerge from renal arteries, and accesorial sexual glands and ductus deferens irrigation are from external iliac artery. Lungs are asymmetric, with three lobes in left and four in right; lower lobe is the largest and deeply bifid in the right lung. Trachea is transversely oval, with rings dorsally imperfect. Oral cavity is small and narrow. Oropharynx communicates with pharynx through palatal ostium. Stomach is pyriform and 6 mm; its greatest breadth on left is 44 mm and in middle 25 mm. Esophagus enters near middle of cavity, and pyloric portion forms an upward curve, on which beginning of duodenum makes a sudden turn. Liver has four lobes, two large and two small, with cystic and lobulus spigelii deeply cleft. Spleen is 25 mm, with a breadth of 22 mm at its lower extremity. Chromosome number is 64, with 128 chromosome arms. Molecular genetic distance (mtDNA sequences of cytochrome-b gene) between the Chilean Chinchilla and the Short-tailed Chinchilla is significant: 5·9% (4·9–6·2%).

Habitat. Steep and dry equatorial-facing slopes, with refuges in rock crevices and boulder piles. The Chilean Chinchilla coexists with a diverse assemblage of rodents such as Bennett’s Chinchilla Rat (Abrocoma bennettii), the Olive Soft-haired Mouse (Abrothrix olivacea), the Long-haired Soft-haired Mouse (A. longipilis), the Common Degu (Octodon degus), and Darwin’s Leaf- eared Mouse (Phyllotis darwini). The Atacama colony is located 44 km from the coast, in the middle of a very arid hill and surrounded by extensive dunes of the Atacama Desert. Vegetation includes Eriosyce aurata (Cactaceae), Gymnophyton flexuosum (Apiaceae), Heliotropium sclerocarpum (Boraginaceae), Nolana sp. (Solanaceae), and Tetragonia microcarpa (Aizoaceae).

Food and Feeding. The diet of the Chilean Chinchilla in the Las Chinchillas National Reserve included the succulent bromeliad Puya berteroniana, but the main plant species eaten was the perennial graminoid Nassella chilensis and secondarily the fern Adiantum chilense, Bridgesia incisifolia (Sapindaceae), Heliotropium stenophyllum (Boraginaceae), and Lobelia polyphylla (Campanulaceae). The Atacama colonies eat E. aurata cactus, which is probably the main source of water and food, with 87% of cacti gnawed on by rodents.

Breeding. Information about reproduction in wild populations of Chilean Chinchillas is very limited, but births apparently occur during austral winter in May–November. In captive individuals, gestation is 105–118 days, with litter sizes of 1–6 young but usually 2–3 young. Lactation normally lasts 6–8 weeks, and minimal period of suckling necessary for survival is 25 days. Sexual maturity of both sexes occurs at c.8 months but may occur as early as 5·5 months. Domestic females have a long estrous cycle (38·1 days ± 0·7 SD, range 16–69 days). A postpartum estrus usually occurs at 57·4 days ± 2·6 SD, whether or not the litter is lost. Vaginal closure membrane of anestrous female may open and close in c.12 hours, but it usually takes 2–4 days. Ovulation in captivity is usually spontaneous. Copulatory plug is usually visible after mating. Single-cell zygotes have been found in fallopian tubes 1–2 days postcoitum (after mating). Fertilization is difficult to detect because some eggs show no traces of polar bodies, sperm, or pronuclei, although some show a single polar body and sperm in the zona pellucida, or a single polar body and second maturation spindle at 2·5 days postcoitum. Polyspermy has not been observed. Preimplantation blastocysts have been detected at 3·5 days postcoitum. Implantation occurs at 5·5 days postcoitum, and it is completely interstitial. Amniotic cavity is formed at 15 days postcoitum, allantois at 25 days, and chorioallantoic placenta at 30 days. Fetal reabsorption occurs frequently and may take place at any stage of pregnancy. Reabsorption occurs even in late stages when skeletal tissue of fetus has formed. Neither placental nor fetal tissue can be recognized in the necrotic mass, but a central blood-filled cavity is typical. Parturition usually occurs in early morning, and the female eats the placenta.

Activity patterns. The Chilean Chinchilla is nocturnal, but it is sometimes crepuscular. In the Atacama region, one individual was seen at midday between large cracked rocks.

Movements, Home range and Social organization. The Chilean Chinchilla is a social and colonial species. There are c.700 individuals in Aucó, with densities of 4·4–72·9 ind/km2 in the Quebrada El Cobre. Some colonies have been identified outside the Aucó reserve in the areas of Quebrada Curico and Quebrada El Cuyano, with 17·5–82·6 ind/km2 and 12·3–58·3 ind/km2, respectively. Isolated colonies form a metapopulation, with frequent local extinctions and colonization of suitable habitat patches. In the Atacama region, the population seems to be small, with densities of 24·7–115·4 ind/km2. Main predators of Chilean Chinchillas in the Coquimbo region are the Culpeo (Pseudalopex culpaeus) and the South American Gray Fox (Lycalopex griseus). The Magellanic horned owl (Bubo magellanicus) is also a predator of the Chilean Chinchilla.

Status and Conservation. CITES Appendix I (wild populations). Classified as Critically Endangered on The IUCN Red List. The Chilean Chinchilla is also classified as critically endangered by the Evolutionary Distinct & Globally Endangered Program of the Zoological Society of London. It is considered extinct in the Antofagasta and Atacama regions of Chile and endangered in northern and central Chile because of drastic past and ongoing population declines, estimated to be more than 90% during the past three generations (15 years). The Chilean Chinchilla occurs in only a small part of the original distribution; it was once widespread in the hills and low mountains between 26° S and 35° S latitude, and is still pressured by illegal hunting and reduced habitat quality. A conservation plan was formulated for the Chilean Chinchilla by CONAF (the National Wildlife Service of Chile) in 2004; the main goal of this conservation plan is to develop scientific research and management of the wild populations in situ and ex situ and to develop a program of education.

Bibliography. Albert (1900, 1901), Bernal & Silva (2003), Bidlingmaier (1937), Cabrera (1960, 1961), Cabrera & Yepes (1960), Cofré & Marquet (1999), Cortés et al. (2003), Espejo et al. (2004), Glade (1988), Grau (1986), Iriarte & Jaksic (1986), Jiménez (1996), Lagos et al. (2012), Miller et al. (1983), Muñoz-Pedreros & Gil (2009), Parera (2002), Redford & Eisenberg (1992), Spotorno & Patton (2015), Spotorno et al. (2004), Tamayo & Frassinetti (1980), Tirado et al. (2012), Valladares (2002), Valladares, Espinosa et al. (2012), Valladares, Zuleta & Spotorno (2014), Woods & Kilpatrick (2005).

3. Short-tailed Chinchilla Chinchilla chinchilla

French: Chinchilla à 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 (Potosí) and Argentina (Jujuy, Catamarca, and Salta).

Descriptive notes. Head–body 300–380 mm, tail up to 100 mm, ear less than 32 mm, hindfoot c.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. Forefoot is 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 process is 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 (×2) = 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 (59·1% 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 c.128 days. The Short-tailed Chinchilla can be sexually mature as early as 5·5 months, but average is closer to c.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 of sterility. 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 km2 in two countries, with a local abundance of 63·1 ind/km2, and it is mentioned in other lists “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 may still be possible to find wild populations in the southern department of Potosí. In Argentina, it is listed as critically endangered. In Chile, the Short-tailed Chinchilla is now considered extinct in the Tarapacá 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), Chacon (1892), Chebez & Oliveras (2008), Cofré & Marquet (1999), Cortés 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), Muñoz-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).

 

Genus LAGIDIUM
Meyen, 1833

4. Ecuadorean Mountain Viscacha Lagidium ahuacaense

French: Viscache d’Équateur / German: Ecuador-Bergviscacha / Spanish: Vizcacha del Ahuaca

Other common names: Ecuadorean Viscacha, Viscacha of Ahuaca

Taxonomy. Lagidium ahuacaense Ledesma et al., 2009, “Cerro El Ahuaca, Parroquia Cariamarga, Canton Calvas, Loja Province, Ecuador (04° 18’ 2” S, 79° 32’ 47” W).”

This species is monotypic.

Distribution. Only known from the type locality in Loja Province, S Ecuador.

Descriptive notes. Head–body 403 mm, tail 400 mm, ear 60 mm, hindfoot 85 mm; weight 2 kg. The Ecuadorean Mountain Viscacha is medium-sized chinchillid, with the longest tail of species of Lagidium. Greatest lengths of skull, basilar, nasal, palatilar, and diastema were significantly larger than those of the Common Mountain Viscacha (L. viscacia). These characteristics make skulls of Ecuadorean Mountain Viscachas appear flatter and more elongated than skulls of the Common Mountain Viscachas. Several measurements, such as least interorbital breadth, breadth of rostrum, and skull height, differ among Ecuadorean Mountain Viscachas, Common Mountain Viscachas, and Wolffsohn’s Mountain Viscachas (L. wolffsohni). Fur color of dorsal area of the Ecuadorean Mountain Viscacha is brown-gray and venter yellowish gray. Ears are blackish, with cream-colored fringes. Hands and feet have black hair, and palms and soles are naked and blackish in color. Dorsally, tail has long coarse maroon hair, with some cream coloration; bottom of tail has short, blackish-brown hair. Tip of tail is covered with long hairs. Vibrissae are mostly black. Body pelage is wooly and grayish brown, with long tail having coarse hair. Anterior dorsal pelage is shorter than posterior pelage. Dorsal fur is grayish, with buffy and black tints. Medial dorsal area has a black longitudinal stripe. Mean lengths of dorsal hair are variable: 24 mm in anterior region of body and 45 mm in posterior region. Dorsal cover hair has a gray basal band; pelage of head resembles dorsal hair but shorter. Mystacial vibrissae are thick and long (18–147 mm) and primarily dark brown, with a few scattered white hairs. Superciliary vibrissae are scarce, up to 71 mm in length, thick, and dark brown. Holotype has one thick, dark-brown, 54-mm genal vibrissa. Skin inside and outside of ears is black, with abundant hairs on upper basal area; rest of outside of ears is covered with fine brown hair, bordered by white hairs, with inside of ear sparsely covered with fine white hair. Hair in mentonian region, flanks of body, sides of throat, and ventral region are creamy white, with a gray basal band and cream-colored white distal band. Fur of inguinal region is ocher, with bands similar to those of ventral region. Length of ventral hair is 15–24 mm in anterior region, 17–31 mm in central region, and 21–31 mm in posterior region. Forefeet are substantially shorter than hindfeet (3·6 mm vs. 8·5 mm). The Ecuadorean Mountain Viscacha has four digits on its forefeet and hindfeet, each with a small and slightly curved claw of 4–6·5 mm. Tips of fingers are large, spherical, and fleshy. Hands and feet have three black pads with small cream-colored spots. First interdigital pad of hand is spherical and smaller than the other two pads; medial pad on foot is larger than the others; thenar and hypothenar are long. Skull is elongated and compact, with long axis slightly curved and a depression in the supraorbital region. Zygomatic arch is relatively broad. Nasal bones are slightly concave at proximal region and curved and inflated toward distal region. Lacrimal capsule is well developed. Frontal bones are constricted in middle region (16·5 mm). Zygomatic process is broad in posterior region. Tympanic bulla is small (15·6 mm) and rounded at base, with external auditory meatus (ear canal) point directed toward the superior regioning up. Post-glenoid foramen is large and cone-shaped. In ventral view, foramen magnum is protuberant (maximum diameter 11·2 mm). Incisive foramina are long and narrow, with a central crease that forms two indentations. Palate is narrow in anterior region and broader in posterior region; it is extended to near M3. Pterigoid crest extends to posterior region of M2. Posterior margin of palate is indented and W-shaped. Mesopterygoid fossa is deep. Oval foramen is large (4·9 mm diameter), located at the posterior region and positioned lateral to pterygoid fossa. Structure of mandible is robust, with a blunt coronoid process. Rear mandible of symphysis located at same level as procingulum of P4. Condyle mandibles are long. Dental rows of the Ecuadorean Mountain Viscacha converge in the anterior region. Dental formula is I 1/1, C 0/0, P 1/1, M 3/3 (×2) = 20. Incisors look whitish, large, and elongated. Anterior surfaces of teeth have grooves. Grooves of upper incisors are yellowish. Lower incisors are distinctively beveled. Upper dental row is 19·9 mm. Molars show low crowns and continuous growth. Molars have a flat crown, with two transverse lamellae of enamel diagonally oriented. P4 is slightly larger than other teeth. Posterior lamella of M1 and M2 angled and curved, with posterior lamellae of M3 forming a straight right angle. Lower dental row is 18·1 mm and converges in the anterior region, similar to upper row. Each molar shows two transverse lamellae of enamel. Cingulum of P4 on labial side has two prominent depressions. In labial region of M1–M3, posterior lamellae more pronounced than those of the anterior region. Lingual region of M1–M3 has a concave cingulum in anterior lamella region; posterior region is convex. Molecular genetic distance (mtDNA sequences of cytochrome-b gene) between the Ecuadorean Mountain Viscacha and other species of Lagidium sampled is significantly large: 9·7% (range 9·3–10·1%).

Habitat. Cerro Ahuaca, a granite inselberg (isolated rocky peak) 2 km from Cariamanga, Loja Province, where the species inhabits the entire peak at elevations of 2000–2480 m. It covers c.120 ha and features extensive rocky areas, ranging from almost unbroken to moderately structured. Rock faces are inclined from c.40° to more than 90°. Large boulders are quite common, especially on lower, gentler slopes. Local climate is distinctly seasonal, with wet season typically in January–April. Precipitation and temperature in Cariamanga average 1264 mm/year and 17·8°C, respectively. Vegetation is now dry montane scrub and heavily deforested, particularly in recent decades. Today, a belt of secondary scrub and forest on lower and middle slopes buffers the mountaintop against surrounding pastures and crop fields. Vegetation at the summit of the inselberg is influenced by fire and cattle grazing and is dominated by Poaceae, especially Melinis minutiflora. This naturalized grass is promoted by repeated fire. Other characteristic plants include Agave americana and Furcraea andina (both Agavaceae), Tillandsia lymanii and Puya sp. (both Bromeliaceae), Armatocereus rupicola and Opuntia sp. (both Cactaceae), and Streptosolen jamesonii (Solanaceae).

Food and Feeding. The diet of the Ecuadorean Mountain Viscacha is poorly understood. Feces and traces of herbivory were present at the base of a rock face at 2310 m, bordering a scrubby cattle pasture, rich in rocky debris.

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. A group of at least two adult and one juvenile Ecuadorean Mountain Viscachas was observed in July 2005. Individuals were resting in close vicinity to a den entrance, a deep rock crevice on a c.80° cliff at 2450 m. They were shy and did not move farther than c.2 m from their den during several hours of observation. Moderate amounts of fecal pellets were found scattered on top of rocks and boulders and in entrances to dens around the summit.

Status and Conservation. The Ecuadorean Mountain Viscacha has not been assessed on The IUCN Red List. Those at Cerro Ahuaca are unknown to local people in Cariamanga, and thus, they are not hunted. Nevertheless, this population faces other threats. Fire is the major threat, widely used to establish and maintain crop fields and pasture at the summit and periphery of the inselberg. This population may have no more than a few dozen individuals, and no other populations are known.

Bibliography. Ledesma et al. (2009), Pacheco (2002), Werner et al. (2006), Woods & Kilpatrick (2005).

 

5. Common Mountain Viscacha Lagidium viscacia

French: Viscache de montagne / German: Eigentliches Bergviscacha / Spanish: Vizcacha de montaña

Other common names: Mountain Viscacha; Northern Mountain Viscacha (Peru and northern Chile), Southern Mountain Viscacha/Southern Viscacha (Bolivia, Chile, and Argentina)

Taxonomy. Lepus viscacia Molina, 1782, type locality not given. Restricted by W. H. Osgood in 1943 to “Chilean Andes; cordillera of Santiago.”

Some authors consider populations in Peru and northern Chile as a valid species (the “Northern Mountain Viscacha,” L. peruanum), but this taxon is not accepted here; taxonomic revision is urgently needed. Monotypic.

Distribution. Andes in C & S Peru, S & W Bolivia, N & C Chile, and NW & W Argentina as far S as 42° S in Chubut.

Descriptive notes. Head–body 295–464 mm, tail 215–376 mm, ear 61–82 mm, hind foot 82–113 mm; weight 0·75–2·1 kg. The Common Mountain Viscacha looks like a large chinchilla but with much longer ears (larger than 65 mm on average). Tail is shorter than head–body length and usually curved dorsally. Head is rounded, short, and massive; ears are always erect. Mouth vibrissae are dark, rigid, and extremely long (150 mm) and always down directed. Fur is dense and soft, covering entire body, except naked, black plantar pads; it is comprised of dense tufts that contain a dozen or so individual hairs; sparse guard hair have slender shafts and stout tips. There is no seasonal molting pattern in adult Common Mountain Viscachas, so molting is likely continuous. Dorsal color is highly variable within and among populations within its ample distribution, but it is typically buff to dark gray; there is a striking dark dorsal stripe whose color is independent of that of the body. Venter is always paler than back, gray washed with buffy yellow. Buff or orange fur usually covers rump and upper thighs, and there may be axillary and inguinal patches of white. Dorsal surface of feet is pale, not black. Hindfeet are narrow with four digits; the fifth digit is extremely short. Forefeet have four digits. All digits terminate in short, curved claws dwarfed by enlarged toe pads. Coarse and pale hair forms a crest along the top of tail and is sharply demarcated from shorter, finer, dark hair along the bottom. Tip of tail is black or orange. Skull is narrow, with long rostrum. Interorbital region is broad (interorbital breadth larger than 16·8 mm), with weakly developed post-orbital processes of frontals that tend to be depressed between orbits. Braincase of the Common Mountain Viscacha is elevated, flat, and rounded, with no sagittal ridge and only poorly developed parietal ridging. Bullae are enlarged, with mastoid portion barely visible. Interparietal is wider than long. Jugal is broad and in contact anteriorly with lacrimal. Floor of infraorbital foramen is smooth, lacking a canal indicative of a nerve passage. Incisive foramina are long and narrow and occupy only c.60% of diastema length. Anterior palate is greatly restricted between premolars. Mandible has elongated and narrowed angular processes and weakly developed ridge lateral to reduced coronoid process for muscle attachment. Each cheek tooth has three, distinctly curved rather than straight laminae, particularly so in M3. In the maxilla, third plate of each tooth is shorter than the other two, with that of M3 forming a posteriorly pointed heel. In mandible, first plate of each tooth is reduced relative to median and posterior plates. Many different specific and subspecific names have been proposed for specimens collected in the wide geographical distribution of the Common Mountain Viscacha, but no general assessment of variation and no consistent geographical patterns have been systematically established and evaluated. Furthermore, molecular genetic distances (mtDNA sequences of cytochrome-b gene) among three geographical populations of the Common Mountain Viscacha are rather intermediate in amount of variation (4·9–7·8%) and geographically incongruent. Therefore, it is highly likely that eventual geographical units can and should be formally recognized. Nevertheless, it was not possible to do so because even the question as to whether this single species is composite or not remains an open issue. As a consequence, recent reviewers made no effort to delineate intraspecific taxa. Chromosome number is 64, with 126 chromosomal arms (specimens referred to L. peruanum).

Habitat. Among rocks, rocky crevices, boulder piles, and vertical cliffs in dry and semi-dry areas in the high plateau of the Andes, also in pre-puna habitats, high-elevation cold desert, and Patagonian steppes. The species ranges from 700 m in Río Negro Province, Argentina, to 4800 m in the Andes. The Common Mountain Viscacha is a poor digger with only small claws, so dens are within natural crevices or under boulder piles. Rare self-dug burrows, typically found under boulders in loose gravel or soil, probably require multiple individuals and perhaps multiple generations to construct. Presence of Common Mountain Viscachas is readily detected by distinctive and numerous fecal pellets that can be found throughout the colony, on top of rocks, or in sheltered crannies; these accumulations became solid masses preserving many organic materials, often called “rat-packs” in the literature.

Food and Feeding. The Common Mountain Viscacha is herbivorous, specializing on green leaves, flowers, fruits, stems, and bark rather than dried plant materials; it eats a wide variety of plants depending on its local environment. It does not accumulate and storage green vegetation for future use but actively forages daily. Individuals descend from their bounder-field or rocky-cliff colonies to feed on green vegetation. In southern Peru, sparse vegetative cover is mostly bunch grasses (Stipa and Festuca) and short shrubs (predominantly species of aster such as Lepidophyllum, Baccharis, and Senecio). In highlands of northern Chile, Common Mountain Viscachas ate ten plant species during winter and seven during summer. Stipa bomanii was most common in diets: 20·9% in winter and 30·1% in summer. Other plants eaten only in winter were Nicotiana longibracteata, Solanaceae (12·1%) and Parastrephia quadrangularis, Asteraceae (9·4%); in turn, Festuca orthophylla (19·9%) was eaten only during summer. Twenty-two plant species (mainly grasses) made up nearly 66% of diets of Common Mountain Viscachas in north-western Patagonia in all seasons. Other species in diets were shrubs (19·7%), forbs (11%), and less than 1% of mosses, lichens, and trees. Grasses such as F. pallescens, Poa sp., and Stipa sp. were commonly eaten; there were preferences for Poa sp. and Stipa sp. and the shrub Schinus patagonicus (Anacardiaceae) in summer. Diets did not vary much seasonally but did vary relative to phenology.

Breeding. In southern Peru and northern Chile, reproductive seasons of Common Mountain Viscachas begin in late October and extends through the wet austral summer (locally called the “Bolivian winter”), with pregnant females observed in October–December and July–August. Females seem to be polyestrous, breeding after they reach c.1 kg; thus, they can have their first estrus in the year they are born. Males reach breeding condition at the same body mass or at c.7 months of age; they are capable of breeding at all seasons thereafter and for the remainder of their life. A large vaginal plug is formed in the female tract following copulation. Ovulation occurs near the time of copulation and is almost always from the right ovary, with implantation nearly always in the right uterine horn. Gestation is c.3 months, with a single, precocial young born at c.225 g. A postpartum estrus and pregnancy are possible, and a single female may have 2–3 litters/year. Lactation from a single pair of mammae lasts c.1 month, but young are fully furred with open eyes at birth and can probably eat plant food immediately. Life expectancy is 2–3 years for both sexes.

Activity patterns. The Common Mountain Viscacha is an agile, quadrupedal bounder, like a rabbit, with propulsion provided by its long hindfeet and hindlimbs and balanced with its long tail. Pearson describes its “reckless, carefree bounds from rock to rock, or ledge to ledge” and long strides of up to 2 m, which makes its capture very difficult. It tends to use latrine areas where multiple generations produce fecal piles or rat-packs. Presence of Common Mountain Viscachas is also evident by occasional tufts of fur lodged in plants or among rocks, bushes stripped of bark, and presence of beaten pathways between outcrops within the larger home range of a colony. Individuals are very vigilant and vocalize warnings with a series of very high-pitched whistles. Both sexes whistle, and all individuals within the group will respond to calls of a single individual.

Movements, Home range and Social organization. The Common Mountain Viscacha is highly gregarious, living in colonies of 4–75 individuals, with an overall density of 0·16 ind/ha because of highly clumped distributions of occupied boulder fields. Each colony has smaller groups of usually 2–5 individuals; these groups appear to be families, although their composition does not remain constant throughout the year. Each group contains a mature male and a female (presumably parents) and 1–3 young of different ages. Oldest male offspring may be sexually mature but still live with their family group. There is no defense of individual or group territories, and entrances of different burrows may be only a few meters apart within the same colony. Individuals occupy the same burrow for long periods. Common Mountain Viscachas are diurnal, up by sunrise, often spending initial daylight hours perched on sentinel boulders where they groom their fur and soak up heat from the morning sun. In the evening, they typically feed until dark, or shortly thereafter, before returning to their shared burrows. Groups and individuals are wary, and all individuals pay attention to sharp alarm whistles of a single individual. They appear to rely most heavily on vision as the dominant sense, but different whistles may be given for aerial and terrestrial predators. Peruvian predators detected by O. P. Pearson in 1948 included the Culpeo (Pseudalopex culpaeus), the Lesser Grison (Galictis cuja), the Puma (Puma concolor), the Andean Mountain Cat (Leopardus jacobitus), and various avian raptors such as the black-chested buzzard-eagle (Geranoaetus melanoleucus). In northern Chile, remains of the Common Mountain Viscacha were found in feces of the Colocolo (Leopardus colocolo) and the Andean Mountain Cat. In central Chile and Argentina, the main predator is the Culpeo. The Common Mountain Viscacha overlaps with grazing or browsing artiodactyls, such as the Vicuna (Vicugna vicugna), the Guanaco (Lama guanicoe), huemuls (Hippocamelus sp.), and several species of small rodents, predominantly the sigmodontine genera Auliscomys, Chroeomys, Chinchillula, Phyllotis, and Punomys. Common Mountain Viscachas typically host roundworms, tapeworms (Cittotaenia), and ectoparasites (e.g. lice genera Gryopus and Philandesia). Use of communal dust baths, which protect insulated properties of fur, and bristle-like combs on hind toes help dislodge troublesome parasites.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The “Northern Mountain Viscacha” (L. peruanum) is treated by IUCN as a distinct species and classified as Least Concern. The Common Mountain Viscacha is locally abundant at many sites; however, it has become rare or extinct in many places where it was historically numerous, particularly near towns or regions with heavy human activities. It has been locally hunted for its meat and skin since pre-Columbian times. In Chile, hunting laws have protected the Common Mountain Viscacha since 1929, and it is classified as vulnerable or in critical danger in some regions of northern Chile. In Argentina, it is classified as vulnerable. In La Paz, Bolivia, local populations currently survive in small, isolated dry patches; one occupied patch decreased 74% in area between 1999 and 2007. If a proposed urban expansion plan for La Paz is approved, c.75% of remaining habitat could be lost in a short time, compromising the future viability of the Common Mountain Viscacha in the area.

Bibliography. Anderson (1997), Barquez et al. (2006), Cabrera (1961), Cabrera & Yepes (1960), Canevari & Vaccaro (2007), Cortés et al. (2002), Crespo (1963), Dunnum et al. (2008), Eisenberg (1974), Galende & Raffaele (2012), George & Weir (1974), Glade (1988), Iriarte (2008), Kleiman (1974), Kleiman et al. (1979), Ledesma et al. (2009), Mann (1978), Morgan & Álvarez (2013), Muñoz-Pedreros & Gil (2009), Osgood (1943), Parera (2002), Pearson (1948, 1949), Redford & Eisenberg (1992), Spotorno & Patton (2015), Spotorno et al. (2004), Tarifa, Aparicio & Yeensens (2007), Tarifa, Fontúrbel et al. (2004), Thomas (1921a), Walker, E.P. (1968), Walker, R.S. et al. (2008), Weir (1974), Weir & Rowlands (1974), Woods & Kilpatrick (2005).

 

6. Wolffsohn’s Mountain Viscacha Lagidium wolffsohni

French: Viscache de Wolffsohn / German: Südliches Bergviscacha / Spanish: Vizcacha de Wolffsohn

Other common names: Wolffsohn’s Viscacha

Taxonomy. Viscaccia wolffsohni Thomas, 1907, “Sierra de los Baguales y de las Vizcachas, lat. 50° 50’ S., long. 72° 20’ W., on the boundary between Chili [= Chile] and Argentina.”

As treated here, this species includes L. boxi as a synonym. Monotypic.

Distribution. SW Argentina and adjacent Chile, known from the Sierra de los Baguales on both sides of the border between Argentina (Santa Cruz Province) and Chile (Magallanes Region) and nearby from Perito Moreno and Los Glaciares national parks in Argentina; it has been also reported in a single locality in Aysén Region, Chile.

Descriptive notes. Head–body 470–475 mm, tail 305–306 mm, ear 62–70 mm, hindfoot 107–113 mm; weight c.2 kg. In many ways, Wolffsohn’s Mountain Viscacha is a larger version of the Common Mountain Viscacha (L. viscacia) but with long fur strongly suffused with orange, short ears, and very bushy tail. Its appearance looks even larger because of the very long and rich fur with woolly hair exceeding 35 mm. General color of head and body is brownish gray, but clay-colored woolly hair gives an overall darker tone to fur. Dark dorsal stripe is barely apparent. Lower cheeks, throat, chest, and belly color are richer and redder, almost tawny. Clear white spots are present on each axilla and each side of inguinal region. Ears are comparatively short, thickly and shortly haired; outside surfaces are black but inner surfaces are clothed with whitish hairs and with a marked line of creamy-tipped hairs running across their bases. Forelimbs are yellowish to tips of toes; hindlimbs are duller, more brownish clay colored. Hindfeet are large and heavy. Tail is finer than in any other viscacha, immensely bushy with hairs forming dorsal crest more than 150 mm. Color of upper crested side is mixed black and buff or ocher-buff; underside of tail is black, finely grizzled with glossy ocher-buff. Skull is comparatively large and heavy, with expanded nasals, short incisive foramina, and less swollen bullae than other species of Lagidium. Molecular genetic distance (mtDNA sequences of cytochrome-b gene) between Wolffsohn’s Mountain Viscacha and the Common Mountain Viscacha is rather large: 7·9% (7·7–8·6%). Chromosome number is 64, with 126 chromosomal arms (in specimens referred to L. boxi).

Habitat. Rocky outcrops in mountainous areas up to elevations of c.4000 m.

Food and Feeding. The Wolffsohn’s Mountain Viscacha is herbivorous, with a diet of tender buds, roots, seeds, and fruits; it also eats hard and coriaceous plants in the genus Festuca (Poaceae). It drinks very little water.

Breeding. There is no specific information available for this species, but a litter of one young has been reported for Wolffsohn’s Mountain Viscacha.

Activity patterns. The Wolffsohn’s Mountain Viscacha is diurnal and gregarious. It lives in caves and rocks 5–10 m apart. In the open, individuals sit erect while sunbathing in the morning. They often take dust baths and give deep whistles when threatened, alerting the colony and producing general running of individuals.

Movements, Home range and Social organization. There is no specific information available for this species, but Wolffsohn’s Mountain Viscacha is reported to occur at elevations of 800–4500 m. It is found in rocky outcrops in mountain areas.

Status and Conservation. Classified as Data Deficient on The IUCN Red List. R. A. Ojeda classified Wolffsohn’s Mountain Viscacha in “danger” category in 2000. It occurs in a few protected areas such as the Perito Moreno and Los Glaciares national parks in Argentina, and Lago Jeineimeni and Tamango national reserves in Chile; c.50% of its known distribution is included in protected areas.

Bibliography. Barquez et al. (2006), Cabrera (1961), Cabrera & Yepes (1960), Canevari & Vaccaro (2007), Crespo (1963), Iriarte (2008), Ledesma et al. (2009), Mann (1978), Muñoz-Pedreros & Gil (2009), Ojeda (2012), Osgood (1943), Parera (2002), Redford & Eisenberg (1992), Spotorno & Patton (2015), Spotorno et al. (2004), Thomas (1907).