175.

Thomas’s Big-eared Brown Bat

Histiotus laephotis

French: Sérotine de Bolivie / German: Thomas-GroRohrfledermaus / Spanish: Histiotus de Thomas

Taxonomy. Histiotus laephotis Thomas, 1916,

“Caiza,” Bolivia.

Since its description, status of H. laephotis has been confusing. It has been previously considered a full species and later a subspecies of H. montanus and H. macrotus . It is now considered a distinct species by most authors based on morphological and ecological evidence. It is frequently mistaken with H. macrotus and H. montanus, therefore, accurate data in literature are scarce. Monotypic.

Distribution. S Peru, Bolivia, N Chile, E slope of Andes in NW Argentina, W & C Paraguay, and S Brazil (Santa Catarina).

Descriptive notes. Head-body ¢.57-68 mm, tail 43-59-2 mm, ear 27-39-5 mm, hindfoot 7-12 mm, forearm 44-50-1 mm; weight 9-14 g. Dorsal hairs of Thomas’s Big-eared Brown Bat are yellowish to dark brown and slightly bicolored, with variable contrast between bases and tips. Ventral hairs are bicolored, with blackish bases and yellowish tips. Ears are pale brown or yellowish, very large, and connected by conspicuous membrane; tragus is wide and long, reaching one-half the ear length. Wings are thin and naked, pale gray or brown, and slightly transparent. Muzzle is inflated and has sparse hairs. Skull is robust; sagittal and lambdoidal crests are practically absent; zygomatic arches have strongly developed postorbital process ofjugal; palate is slightly concave centrally; caudal spine is well developed; and tympanic bullae are large and rounded.

Habitat. Forested areas at known elevations of 350-3686 m. Thomas's Big-eared Brown Bat has been captured in Atlantic rainforest, thorn forests, and pine forests.

Food and Feeding. No information.

Breeding. A lactating Thomas’s Big-eared Brown Bat was caught in November in Argentina.

Activity patterns. Roosts of Thomas's Big-eared Brown Bats were found in a wooded storage barn. Echolocation calls have QCF components. Calls sweep down from c.38 kHz to ¢.26 kHz, with duration of c.1-3 milliseconds. Interpulse interval averages 94 milliseconds, and peak frequency is ¢.30 kHz.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Least Concern on The [UCN Red List. Thomas's Big-eared Brown Bat is not abundant locally, and its habitatis in significant decline.

Bibliography. Acosta & Venegas (2006), Autino et al. (1999), Barquez & Diaz (2001, 2008a), Barquez etal. (1999), Handley & Gardner (2008), Lopez-Gonzélez et al. (1998), Miranda et al. (2007), Ossa et al. (2015), Simmons (2005), Thomas (1916b).