492.

Escalera’s Myotis

Myotis escalerai

French: Murin d'Escalera / German: Iberische Fransenfledermaus / Spanish: Ratonero ibérico

Other common names: Iberian Natterer's Bat, Iberian Natterer's Myotis

Taxonomy. Myotis escalerai Cabrera, 1904,

Valencia, Spain.

Subgenus Myotis; myotis species group. See M. nattereri . Monotypic.

Distribution. Iberian Peninsula N to the French Pyrenees and Balearic Is.

Descriptive notes. Head-body 42-50 mm, tail 42-50 mm, ear 15- 1-18 mm, hindfoot 6-7-10, forearm 37- 1-42 mm; weight 4.5-6- 3 g. Escalera’s Myotis is extremely similar to Natterer’s Myotis (M. natterer), the Cryptic Myotis (M. crypticus), and the Zenati Myotis (M. zenatius). Its dorsum is brownish to grayish, and venteris pale grayish to whitish. Young are much darker than adults. Edge of uropatagium hasdistinct line of bristles, typical of the nattereri species complex. It is clearly different from the Cryptic Myotis because it has noticeably line of hair pointing inward and another line of hair, shorter, pointing outward. Wings are clearly attached to metatarsus, a characteristic that differentiates it from sympatric Cryptic Myotis whose wing membrane starts at base of the foot. Calcaris clearly S-shaped. It has a naked face, pinkish (especially area surrounding eyes), with long muzzle and relatively long ears that surpass tip of nose when flattened horizontally, which are also foldable due to multiple folds presentin the outside edge. Skull is small and delicate with high braincase and strongly concave forehead regions; there are no sagittal or occipital crests. P* is more than one-half height and about three-quarters crown area of P? and is within tooth row; lower molars are myotodont. Chromosomal complement has 2n = 44 and FNa = 50 (Spain).

Habitat. Wide variety of habitats from dry areas (e.g. Ebro Basin) to montane deciduous and coniferous forests, oak woodlands, parks, and orchards (e.g. olive and almond trees), usually at lower elevations but up to ¢. 1400 m.

Food and Feeding. Escalera’s Myotis probably has similar foraging behavior and feeding preferences to Natterer’s Myotis and is able to glean prey from surfaces of leaves and directly from the ground with its tail membrane. It can be seen foraging close to vegetation, branches, and leaves searching for potential prey.

Breeding. Maternity colonies of Escalera’s Myotis can contain from tens to 800 females and young. Temperature in summer roosts is 17-21°C. Mating activities take place in autumn (September—November) during swarming period when numbers of males increase significantly in cave-rich areas. Young are usually born in May. Young are completely independent at less than two months old in July and leave maternity colonies. Escalera’s Myotis readily switch roosts.

Activity patterns. Escalera’s Myotis is cave dwelling and can be found in natural and artificial caves, mines, tunnels, and other undergroundsites, generally hidden in cracks and crevices. There are isolated reports of roosts in tree holes or even bridges. Echolocation calls are very similar to those from Natterer’s Myotis, with short and highly modulated pulses,starting at 120-140 kHz and ending at 15-20 kHz (broad frequency range of ¢.130 kHz). Discrimination of its calls from other species of Myotis is difficult and controversial.

Movements, Home range and Social organization. Escalera’s Myotisis considered sedentary. It will share roosts with other species such as the Long-fingered Myotis (M. capaccicnii) and Geoffroy’s Myotis ( M. emarginatus).

Status and Conservation. Classified as Least Concern on The IUCN Red List. Disturbance, vandalism, and destruction of caves are major threats to Escalera’s Myotis and can affect large colonies. Two ofthe largest colonies of Escalera’s Myotis have recently disappeared due to inappropriate fencing. It might be more common than expected, especially in the most humid and coldest regions in its distribution.

Bibliography. Cabrera (1904), Coraman et al. (2019), Evin et al. (2009), Ibanez et al. (2006), Juste etal. (2019), Puechmaille, Allegrini et al. (2012), Ruedi et al. (2019), Salicini et al. (2013).