Lagidium ahuacaense
Creators: name: Don E. Wilson
name: Thomas E. Lacher, Jr
name: Russell A. Mittermeier
Publisher: name: Lynx Edicions
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Rodentia
Chinchillidae
Lagidium
Lagidium ahuacaense

description: 4.
Ecuadorean Mountain Viscacha
Lagidium ahuacaense
French: Viscache d'Equateur / 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” wW).”
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. wviscacia). 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 oftail 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. Dorsalfur is grayish, with buffy and black tints. Medial dorsal area has a black longitudinalstripe. 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, 54mm genal vibrissa. Skin inside and outside of earsis black, with abundant hairs on upper basal area; rest of outside of earsis 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 creamcolored 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 M?. 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 formulaisI 1/1, C0/0,P 1/1, M 3/3 (x2) = 20. Incisors look whitish, large, and elongated. Anterior surfaces of teeth have grooves. Grooves of upper incisors are yellowish. Lowerincisors 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 ¢.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 bufters 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 ¢.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).
description: Published as part of Don E. Wilson, Thomas E. Lacher, Jr & Russell A. Mittermeier, 2016, Chinchillidae, pp. 462-481 in Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I, Barcelona :Lynx Edicions on pages 479-480, DOI: 10.5281/zenodo.6585600