411.

Atacama Myotis

Myotis atacamensis

French: Murin dAtacama / German: Atacama-Mausohr / Spanish: Ratonero de Atacama

Other common names: Atacaman Myotis

Taxonomy. Vespertilio atacamensis Lataste, 1892,

San Pedro de “ Atacama,” Antofagasta, Chile.

Subgenus Pizonyx; albescens species group. Myotis atacamensis was considered a subspecies of M. chiloensis, but studies based on morphology and molecular data indicate clear distinction between the two.

Monotypic.

Distribution. From CW Peru to CWChile.

Descriptive notes. Head-body c.41 45 mm, tail 31-40 mm, ear 13-14 mm, hindfoot 5-8 mm, forearm 30-8-34:- 1 mm: weight 3-4 g. Fur is long and silky (dorsal fur 7-9 mm; ventral fur 6-7 mm). Ventral and dorsal hairs are strongly bicolored, ventral hairs are black on bases and whitish on tips, and dorsal hairs are black on bases and light ocherous buff on tips. Teeth are small. Ears are medium-sized, extending forward halfway from eye to nostril. Membranes are mummy brown; plagiopatagiumis attached to foot at toes by a broad band of membrane; and fringe ofhairs along trailing edge of uropatagium is present. Skull is small (greatest length ofskull 12:6-13- 8 mm); occipital regionis rounded; forehead slopes steeply, with inflated braincase; rostrum is narrow and short; sagittal and lambdoidal crests are generally absent or, when present, are very low. P? is aligned in tooth row and visible in labial view. Bacula are small and slight in width from proximalto distal end, and average measurements are: 0-50 mm long, 0-20 mm deep, and 0-27 mm wide. Wing morphology and echolocation are typical of aerial insectivore that uses cluttered spaces.

Habitat. Arid and semiarid scrublands and thorn and sclerophyll forests from sea level up to elevations of ¢. 3475 m.

Food and Feeding. The Atacama Myotis feeds exclusively on insects captured in flight in open habitats and over watercourses.

Breeding. Atacama Myotis seems to reproduce in September-December, with females giving birth to one young per pregnancy.

Activity patterns. In semiarid highlands, foraging activity of the Atacama Myotis begins one hour before dusk and lasts for c.3 hours. Tree cavities, crevices in rocky outcrops, caves, abandoned mines, and other human buildings (e.g. house roof,attic and drainage pipeline) are used as roosts. Mean call components are start frequency of 67 kHz, end frequency of 47-7 kHz, peak frequency of 52 kHz, duration of 3-3 milliseconds, and interval between pulses of 134-9 milliseconds.

Movements, Home range and Social organization. Colonies of Atacama Myotis can have more than 30 individuals.

Status and Conservation. Classified as Endangered on The IUCNRed List. Although the Atacama Myotisis still reasonably widespread,it is very dependent on specific habitats that have become severely fragmented. Surveys along coastal deserts of Peru and Chile found only a few populations that were disjunct from each other. Area of occupancyis less than 200 km *. With predicted loss of habitat, population of the Atacama Myotisis expected to decline more than 30% in the next three generations.

Bibliography. Galaz & Yanez (2006), Galaz et al. (2009), Iriarte (2008), LaVal (1973b), Ossa et al. (2017), Rodriguez-San Pedro, Allendes, Castillo et al. (2014), Rodriguez-San Pedro, Allendes & Ossa (2016), Stadelman et al. (2007), Vargas-Rodriguez et al. (2016).