388.

Red Myotis

Myotis ruber

French: Murin rouge / German: Rotes Mausohr / Spanish: Ratonero rojizo

Taxonomy. Vespertilio ruber E. Geoffroy Saint-Hilaire, 1806,

“ Paraguay.” Based on neotype selection,restricted by R. K. LaVal in 1973b to “Sapucay [Neembuct Department], Paraguay.”

Subgenus Pyzonix; ruber species group.

Monotypic.

Distribution. NE, SE & S Brazil, E Paraguay, NE Argentina, and Uruguay.

Descriptive notes. Head-body c¢.49 50 mm, tail 33-44 mm, ear 11-14 mm, hindfoot 7-10 mm, forearm 33-9-42.1 mm; weight 5-9 g. The Red Myotis is morphologically similar to its Neotropical congeners. Fur is medium long (dorsal fur 6-8 mm; ventral fur 4-7 mm) and woolly. Dorsal hairs are subtly bicolored, with russet bases (two-thirds total length) and only slightly lighter tips. Ventral hairs are bicolored, with dark brown bases (two-thirds total length), bright yellow-ochertips, and strong contrast between bases and tips. Ears are of medium length, extending forward halfway from eye to nostril. Membranes are cinnamon-brown; plagiopatagium is broadly attached to foot at bases of toes; claws are often reddish. Fringe of hairs along trailing edge of uropatagium is absent; fur is thick on basal one-third of dorsal uropatagium, extending one-third to one-half the distance from knee to ankle. Baculum is small, with poorly developed structural features; it is little more than a rod, flattened and laterally expanded at one end. Skull is robust and moderate in size (greatest skull lengths 14-6-15- 8 mm); parietal is inclined forward; posterior region of skull, formed by interparietal and supraoccipital bones, usually does not project beyond posterior border of occipital condyles; and sagittal and lambdoidal crests are present, ranging from medium to high. P? is generally aligned with other upper premolars. Chromosomal complement has 2n = 44 and FN = 50, with three large and one small metacentric and 17 acrocentric pairs of autosomes. Large X-and small Y-chromosomes are submetacentric.

Habitat. Highland rainforests and semideciduous forest relics (north-eastern Brazil), dense montane forest (south-eastern Brazil), ombrophilous Atlantic Forest (southern Brazil), semideciduous forest and grassland Pampa (Paraguay, Argentina, and Uruguay), agricultural landscapes, and urban forest fragments at elevations of 500— 1500 m. Records indicate that the Red Myotis has strong association with subtropical habitats and appears more common in primary forests.

Food and Feeding. Red Myotis forage in forested areas and over water. In southern Brazil, diets include various insects, particularly Coleoptera and Diptera, caught in flight.

Breeding. In southern Brazil, pregnant Red Myotis were recorded in June and August— November, with concentrated peak in the last two months. Reproduction seems to be polyestrous, with greater reproductive activity in summer.

Activity patterns. Red Myotis emerge just before sunset. Roosts include hollow trees, cracks in rocks, and human structures (e.g. house roofs). Echolocation calls have strongly FM initial component, terminating with short CF component. Mean call parameters are lowest frequency of 58 kHz, highest frequency of 65 kHz, and call duration of 5 milliseconds.

Movements, Home range and Social organization. A colony of Red Myotis roosted in a peri-urban shed in Uruguay with Small Big-eared Brown Bats ( Histiotus montanus) and Brazilian Free-tailed Bats (Tadarida brasiliensis).

Status and Conservation. Classified as Near Threatened on The IUCNRed List. The Red Myotis still seems reasonably widespread, but it is dependent on highly fragile habitat and is in significant decline due to habitat conversion by humans.

Bibliography. Acosta (1950), Arias-Aguilar et al. (2018), Barquez & Diaz (2008b), Barquez et al. (1999), Ber nardi et al. (2014), Geoffroy Saint-Hilaire (1806), LaVal (1973b), Lépez-Gonzélez et al. (2001), Lutz et al. (2012), Moratelli & Morielle-Versute (2007), Sbragia & Pess6a (2008), Sousa et al. (2004), Thomas (1902d), Weber et al. (2010), Wilson (2008b).