Micronycteris megalotis

12. Litde Big-eared Bat Micronycteris megalotis French: Micronyctere oreillard / German: Kleine GroRohrblattnase / Spanish: Micronicterio comin de Gray Other common names: Brazilian Big-eared Bat Taxonomy. Phyllophora megalotis J. E. Gray, 1842, “Brazils.” Restricted by A. Cabrera in 1958 to Perequé, Sao Paulo, Brazil. J. KE. ‘Gray in 1866 first used the current name, M. megalotis. Later, G. S. Miller in 1898 described the subspecies mexicana and macrotis. C. C. Sanborn in 1949 extended and revised the genus, restricting megalotis to subgenus Micronycteris and considering three subspecies: megalotis, mexicana, and macrotis. N. B. Simmons in 1996 suggested that mexicana is not a subspecies of megalotis but a subspecies of microtis, recognizing the latter as a species distinct from megalotis. Under that view, M. megalotis was confined to South America and M. macrotis (sensu stricto) from Brazil to western Nicaragua. B. K. Lim and collaborators in 1999 based on skull morphology, B. F. S. Simoes in 2012 based on morphologic and morphometric data from Brazil, and C. A. Porter and collaborators in 2007 based on phylogenetic analyses did not support the occurrence of a cladogesic event separating these two species. Moreover, some authors suggested that M. megalotis (including microtis) comprised a cryptic complex, whose morphological diversity required proper assessment. These authors refrained from making any definitive changes in taxonomy of M. megalotis, pending additional studies and resolution of species boundaries. Thus, M. microtis, formerly classified as a subspecies of M. megalotis, is here considered as a full species. Monotypic. Distribution. N South America from Colombia to SE Peru, N Bolivia, and SE Brazil; also on the Lesser Antilles (Margarita, Grenada, Trinidad, and Tobago Is). Descriptive notes. Head-body 38-59 mm, tail 10-16 mm, ear 17-1-23 mm, hindfoot 7-4-10 mm, forearm 31-5-36-4 mm; weight 5:5-6-3 g. The Little Big-eared Bat is a small species of Micronycteris. Greatest lengths of skulls are 17:5-20-2 mm. Dorsum is brown; one-quarter to one-half of hair bases are pale to white on anterior part of back, whereas hairs on posterior part of back have pale bases comprising one-third to onehalf of each hair. Venter is brown, although color can vary geographically and within populations. Dorsal and ventral hair lengths are 8-11 mm. Forearm is naked. Wings are short and wide, and they are attached to bases of feet. Calcar is longer than foot. Tail reaches center of uropatagium and only tip protrudes freely. Uropatagium and tail are naked. Ears are large, rounded, and connected by transverse band that extends overhead with shallow notch at middle of upper margin of band; transverse bands of females and young males are much reduced. Hair lengths on outside of medial onethird of ear pinna are 5-8 mm, longer than in other species of Micronycteris; although there is variation among populations, fur length can help distinguish similar species where they occur in sympatry. Some adult male Little Big-eared Bats have a developed triangular cutaneous fossa behind interauricular band. Noseleaf is small and pointed. Skull is small and slender, rostrum is narrow, and braincase is large, swollen, and elevated above rostrum. Sagittal crest is weak, and mastoid breadth is less than zygomatic breadth. Teeth are robust. I' is large and chisel-shaped, and I? is small. Lower incisors are short, forming continuous row between canines. P* and P* are subequal in length, P,, P,, and P, are about the same size, and in some cases,P, is slightly larger than either P, or P,. Little Big-eared Bats and Common Big-eared Bats (M. microtis) have identical chromosomal complement of 2n = 40 and FN = 68. Habitat. Various habitats such as evergreen and deciduous forests, primary and secondary forests, swamps, clearings, pastures lands, and urban areas up to elevations slightly above 3000 m. Food and Feeding. The Little Big-eared Bat is a gleaning insectivore. Detailed studies on natural history and feeding habits of supposedly Little Big-eared Bat were conducted in Central America and Mexico, but these studies certainly refer to the Common Big-eared Bat. Given the close relationship between these two species,it is expected that feeding habits of both species are very similar. As other insectivorous bats, feeding habitats of the Little Big-eared Bat likely depend on local conditions, such as relative abundance of insects; thus, predation behavior is opportunistic. Studies on the Little Big-eared Bat in South America, certainly referring to this species in its current classification, showed that species of Lepidoptera and Coleoptera were the two primary food sources, depending on habitat. In Ecuador, lepidopterans dominated remains in a roost in a disturbed habitat (pasture lands), but coleopterans were dominant in remains in a roost at the base of a tree in a primary forest. In Atlantic Forest in Brazil, Little Big-eared Bats preferred species of Coleoptera to Lepidoptera. Grasshoppers, crickets, katydids (Orthoptera), cicadas (Homoptera), dragonflies (Odonata), and cockroaches (Blattodea) are also common in diets of congeners ofthe Little Big-eared Bat, and some of these groups represent nearly 50% of diets of Common Big-eared Bats in Central America. Although no information regarding prey-seeking strategies of the Little Big-eared Bat is available,literature suggests that most of these insect groups, either diurnal or nocturnal, are noisy and move along the ground or among foliage, and perhaps sounds made by them attract Little Big-eared Bats. Evidence also suggests that the Little Big-eared Bat uses echolocation to find prey. Fruits are important in diets of Little Big-eared Bats; they are known to feed on fruits of banana, guava, Syzygium jambos (Myrtaceae), Cecropia sp. (Urticaceae), Eriobotrya japonica (Rosaceae), and Solanum paniculatum (Solanaceae) in Brazil. In Trinidad, they plucked small ripe guavas from a tree while hovering in the air and carry them to a nearby tree to eat. Breeding. In Colombia, Venezuela, and Trinidad and Tobago, pregnant Little Bigeared Bats have been reported in February-April and June. Lactation has been noted in May-June. In Peru, Bolivia, and Brazil, pregnant females have been recorded in February-August and lactating females in June, August, and November. The Little Big-eared Bat might have two reproductive cycles each year, both associated with rainy seasons, but births in Peru were noted in dry and rainy seasons. Activity patterns. Little Big-eared Bats are nocturnal. On bright moonlight nights, they remain in roosts until the moon goes down and will leave roosts c.15 minutes before it is too dark for an observer to see it. Observations suggest that day roosts are also used as feeding roosts. Little Big-eared Bats are slow flying, highly maneuverable, foliage gleaners and capable of hovering. Relative broad wings could produce lift with slower motion. Little Big-eared Bats usually roost under fallen trees; in hollow trees, cavities in standing trees, smaller cavities in branches or roots, small caverns, culverts, crevices in rocks, termite nests; and under bridges, tunnels, and buildings. In hollow trees, they prefer to roost near openings and might also prefer places with someillumination. Movements, Home range and Social organization. In South America, Little Big-eared Bats roost with Silky Short-tailed Bats (Carollia brevicaudum), Seba’s Short-tailed Bats (C. perspicillata), Little Big-eyed Bats (Chiroderma trinitatum), Common Vampire Bats (Desmodus rotundus), White-winged Vampire Bats (Diaemus youngii), Miller's Longtongued Bats (Glossophaga longirostris), Pallas’s Long-tongued Bats (G. soricina), Hairy Bigeared Bats (Micronycteris hirsuta), Tiny Big-eared Bats (M. minuta), Greater Spear-nosed Bats (Phyllostomus hastatus), ¥ringe-lipped Bats (Trachops cirrhosus), Parnell’s Common Mustached Bats (Pleronotus parnellii), Common Black Myotis (Myotis nigricans), Trinidadian Funnel-eared Bats (Natalus tumidirostris), Lesser Dog-like Bats (Peropteryx macrotis), Greater Sac-winged Bats (Saccopteryx bilineata), and Lesser Sac-winged Bats (S. leptura). Roosting groups of Little Big-eared Bats rarely exceed twelve individuals of both sexes. Observations suggested that they regularly foraged in small familiar areas. Status and Conservation. Classified as Least Concern on The IUCN Red List. Bibliography. Alonso-Mejia & Medellin (1991), Andersen (1906a), Belwood (1988a, 1988b), Brosset & Charles-Dominique (1991), Brosset et al. (1996), Cabrera (1958), Carter et al. (1981), Gardner (1977b), Graham (1988), Gray (1842, 1866c), Hartman (1963), Hershkovitz (1949), Lasso & Jarrin-Valladares (2005), LaVal & LaVal (1980b), Lim, B.K. et al. (1999), Miller (1898a), Morales-Martinez (2017), Nogueira, Peracchi & Moratelli (2007), Porter et al. (2007), Rengifo et al. (2013), Sanborn (1949a), Simmons (1996), Simmons & Voss (1998), Simoes (2012), Voss etal. (2016), Wilson (1979).

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