268.

Southern Yellow Bat

Lasiurus ega

French: Lasiure jaune / German: Sidliche Haarschwanzfledermaus / Spanish: Lasiuro amarillo

Taxonomy. Nycticejus ega P. Gervais in Castelnau, 1836,

“Ega, ville du Brasil,” Amazonas, Brazil.

Recent molecular studies based on mtDNA and nDNA showed genetic differences between North American and South American populations of L. ega, suggest ing they are distinct species. Nevertheless, any taxonomic change was discarded, and broader analysis of subspecies is needed. Lasiurus ega 1s in the Yellow Bat group. Four subspecies recognized.

Subspecies and Distribution. L.e.egaP.Gervais,1856—EoftheAndesinColombia,Venezuela,Peru,andBolivia,Guyana,Suriname,andN&CBrazil;alsoonTrinidadI.

L.e.argentinusThomas,1901—SBoliviaandNEBrazilStoParaguay,W&SUruguay,andECArgentina.

L.e.fuscatusThomas,1901—WColombiaandWEcuador.

L. e. panamensis Thomas, 1901 — from SE Texas S along the Gulf coast to S Mexico and through Central America to N Colombia and NW Venezuela.

Descriptive notes. Head-body ¢.57- 5-77 mm, tail 43-68 mm, ear 14-20 mm, hindfoot 6-11- 5 mm, forearm 40- 5-52 mm; weight 13-20 g. Dorsal hairs are bicolored, with dark or brown bases, orange to pale yellowish tips, and inconspicuous to heavy blackish wash. Ventral hairs are bicolored, with dark or brown bases and olivaceous to yellowish tips, and lighter than dorsum. Dorsal and ventral hairs are not frosted. Ventral hairs reach membranes next to body, extending along forearm to fifth finger. Ears are small, rounded, and fringed with yellow hairs at internal base. Tragus is broad and reaches slightly more than 50% the ear length. Face is blackish. Muzzle is short and broad. Wing membranes are naked and light brown, with whitish edges. Uropatagium is partially furred, with hairs reaching only one-half ofits length and contrasting or not with dorsalfur. Calcar has slight keel and reaches almost entire extent of free margin of uropatagium. Skull is short and broad. Rostrum slopes in front and almost aligns to braincase. Braincase is high and rounded; auditory bullae are well developed; zygomatic arches are slender; basisphenoid pits are distinct, long, and narrow. I* is close to C'!, unicuspid and pointed; P? is usually absent; M' and M* lack hypocone; M? is reduced; lower incisors are tricuspid and almost perpendicular to jaws; and lower molars have developed cusps. Dental formulais11/3,C1/1,P 1-2/2, M 3/3 (x2) = 30-32. Chromosomal complement has 2n = 28 and FN = 46, with seven pairs of large metacentric and submetacentric autosomes, three pairs of medium metacentric autosomes, three pairs of small acrocentric autosomes, medium submetacentric X-chromosome, and small acrocentric Y-chromosome.

Habitat. Variety of xeric to moist habitats including tropical dry forests, subtropical and tropical moist forests, elfin forests, savannas, pastures, dense forests, and banana and palm groves, often over streams, rivers, ponds, swimming pools, and along roads, from sea level up to elevations of ¢. 1860 m.

Food and Feeding. The Southern Yellow Bat seems to have rapid and maneuverable flight, commonly capturing insects over water. Its diet varies across its wide distribution. In Mexico, it seems to prey mainly on Coleoptera and then other prey; in Paraguay, stomachs contained Diptera, Lepidoptera, Coleoptera, and Heteroptera; and in Brazil, stomachs contained Lepidoptera and Coleoptera .

Breeding. The Southern Yellow Bat is monoestrous. In Paraguay, mating begins in May (autumn), and ovulation takes place c.3 months later. After 3-3-5-months gestation, parturition occurs in late November and early December (spring or early summer), and seems to be earlier in areas near to the equator. Lactation seemsto last at least 60 days. Pregnant females were captured in late April in Guatemala, November in Brazil, and mid-November in Argentina. Lactating females were captured in June in Mexico and May in Costa Rica and Honduras. Parturition was observed in spring in Uruguay and late January in Argentina. Pregnant females bear 1-4 embryos (typically three).

Activity patterns. Southern Yellow Bats are crepuscular/nocturnal. They are probably more active during the first five hours of the night, being mostly captured from right before dusk until close to midnight. Roosting sites are mainly in dead palm leaves but also building crevices and holes, banana leaves, abandoned parrot nests ( Psittacidae), and caves. Echolocation calls are c.9 milliseconds, with narrowband and single harmonic, and sweep from c¢.51-5 kHz to ¢.29 kHz. Predators include owls and rufousbrowed peppershrikes (Cyclarhis gujanensis).

Movements, Home range and Social organization. The Southern Yellow Bat is solitary, but up to 20 individuals occurred in the same roost. Migration movements are unknown, but it has been observed c. 145 km offshore in Brazil and 335 km offshore in Argentina. The season when the second observation occurred and direction of flight (northward) suggested that migratory movements toward the equator might occur. In Minas Gerais, Brazil, it cohabits caves with Common Vampire Bats (Desmodus rotundus) in Mexico, it shared a roost with Sinaloan Mastiff Bats (Molossus sinaloae); and in Texas, it roosted with the Northern Yellow Bat ( Lasiurus intermedius).

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Southern Yellow Bat is widely distributed, locally common, and presumably has large population. It occurs in protected areas, and no major threats are known.

Bibliography. Alvarez-Castafieda & Gonzalez-Ruiz (2018), Baird et al. (2015), Barquez & Diaz (2016¢), Barquez et al. (1999), Bianconi & Pedro (2017), Bickham (1987), Collen (2012), Costa et al. (2016), Gardner & Handley (2008), Handley (1960), Kurta & Lehr (1995), Mikula et al. (2016), Morales et al. (2014d), Novaes, Garbino et al. (2018), Simmons (2005).