Vampyressa thyone, Thomas, 1909

Don E. Wilson & Russell A. Mittermeier, 2019, Phyllostomidae, Handbook of the Mammals of the World – Volume 9 Bats, Barcelona: Lynx Edicions, pp. 444-583 : 559

160.

Northern Little Yellow-eared Bat

Vampyressa thyone

French: Vampyresse thyoné / German: Nordliche Kleine Gelbohrfledermaus / Spanish: Vampiresa de Thyone

Taxonomy. Vampyressa thyone Thomas, 1909 ,

“Chimbo, near Guayaquil [Bolivar], Ecuador. Alt. 1000° [= 305 m].”

Vampyressa thyone was associated with V. minuta by G. S. Miller, Jr. in 1912 (from Panama) and V. venilla by O. Thomas in 1924 (from northern Peru); however, it more commonly has been treated as a synonym or subspecies of V. pusilla . B. K. Lim and collaborators in 2003 confirmed that it is a distinct species. Monotypic.

Distribution. From S Mexico (Veracruz, Oaxaca, Tabasco, and Chiapas) through Central America (except dry Pacific slope and Yucatan Peninsula) to W Colombia, Venezuela, Guyana, French Guiana, and W Ecuador, and through the Amazon Basin of Colombia, Venezuela, N & W Brazil, Ecuador, Peru, and Bolivia.

Descriptive notes. Head-body 43-52 mm (tailless), ear 11-15 mm, hindfoot 7-10 mm, forearm 29-34 mm; weight 6-10 g. The Northern Little Yellow-eared Bat is very small, among the smallest in the family. Dorsal pelage is pale brown; hairs are tricolored, with brown bases, central portion creamy-white, and paler tips. There is no median back stripe. Facial stripes are indistinct, most often looking like small paler spots above and below eyes. Tragus, entire base of ear, and upper edges of ears are yellow; noseleafis mostly brown, with yellow edges. Uropatagium is short, with light fringe of yellowish hairs along middle posterior border. Legs and feet are sparsely haired. Forearms, fingers, and thumbs are brown. Skull has short, broad rostrum, and postorbital processes are weakly developed. I? are elongated and roughly evenly bilobate, converging distally but not in contact at tips, and more than twice as high as I*. Upper molars are broader than long; lower incisors are small, completely filling space between canines, and their cutting edges are faintly trilobate. P® is one-half or less the size of P*, and the latteris triangular, with well-developed cingulum. M, is quadrate-shaped, with large protoconid and small hypoconid. M, has large metaconid and blade-like entoconid of about the same length as metaconid. M, is absent. Dental formula is I 2 /2, C 1/1, P 2/2, M 2/2 (x2) = 28. There are three chromosomal complements: 2n = 18 and FN = 20 in Honduras and Nicaragua; 2n = 23/24 and FN = 22 in Colombia and 2n = 22/23 and FN = 22 in northern Peru, with a sex-chromosome system XXXXXX.Y, with the Y-chromosome translocated to the autosomes.

Habitat. Mostly well-preserved humid forests and also disturbed secondary forests, rarely croplands, modified habitats, and dry habitats at elevations up to 1500 m (most commonly below 800 m).

Food and Feeding. Fruits in diets of Northern Little Yellow-eared Bats include a high proportion of Ficus spp. ( Moraceae ) and other small fruits; it qualifies as a fig specialist in Panama. Samples from Costa Rica showed a cultivated fruit-bearing tree as a source of food. Most stomach contents had fruit pulp.

Breeding. Northern Little Yellow-eared Bats reproduce twice a year, with young born late in dry season and middle of wet season. Pregnant and lactating females have been recorded year-round, suggesting bimodal polyestry.

Activity patterns. Greatest activity of Northern Little Yellow-eared Bats occurs during the first two hours after sunset, but they can be active throughout the night. They are usually caught in nets set across streams, preferring to fly in forest subcanopies rather than understories. Known roosting sites include bushes and tree branches. They make tents from Philodendron and other aroids. Availability of suitable leaves to build tents could determine distribution and local abundance.

Movements, Home range and Social organization. Roosting groups of Little Yelloweared Bats are composed of one to five individuals.

Status and Conservation. Classified as Least Concern on The IUCN Red List. Although the Northern Little Yellow-eared Bat is not locally common, its distribution is very wide, diminishing potential threats to its overall population.

Bibliography. Arroyo-Cabrales (2008b), Baker et al. (1973), Bonaccorso (1979), Davis & Dixon (1976), Gardner (1977a, 1977b), Gomes et al. (2016), Miller (1912), Lewis & Wilson (1987), Lim, B.K., Pedro & Passos (2003), Reid (2009), Thomas (1924a), Timm (1984), Wilson (1979).

Figures

143. Guadeloupean Big-eyed Bat (Charoderma tmprovisum), 144. Little Big-eyed Bat (Charoderma trinitatum), 145. Salvin’s Big-eyed Bat (Chiroderma salvini), 146. Hairy Big-eyed Bat (Chiroderma villosum), 147. Brazilian Big-eyed Bat (Chiroderma doriae), 148. Vizotto’s Big-eyed Bat (Chiroderma vizottoi), 149. Bidentate Yellow-eared Bat (Vampyriscus bidens), 150. Brock’s Yellow-eared Bat (Vampyriscus brocki), 151. Striped Yellow-eared Bat (Vampyriscus nymphaea), 152. Baker’s Tent-making Bat (Uroderma bakeri), 153. Common Tent-making Bat (Uroderma bilobatum), 154. Pacific Tent-making Bat (Uroderma convexum), 155. Davis’s Tent-making Bat (Uroderma dauvisi), 156. Brown Tent-making Bat (Uroderma magnirostrum), 157. Kalko’s Yellow-eared Bat (Vampyressa elisabethae), 158. Melissa’s Yellow-eared Bat (Vampyressa melissa), 159. Quechuan Yellow-eared Bat (Vampyressa sinchi), 160. Northern Little Yellow-eared Bat (Vampyressa thyone), 161. Southern Little Yellow-eared Bat (Vampyressa pusilla), 162. MacConnell’s Bat (Mesophylla macconnelli), 163. Caracciolo’s Stripe-faced Bat (Vampyrodes caraccioli), 164. Great Stripe-faced Bat (Vampyrodes major)

Distribution. From S Mexico (Veracruz, Oaxaca, Tabasco, and Chiapas) through Central America (except dry Pacific slope and Yucatan Peninsula) to W Colombia , Venezuela , Guyana , French Guiana , and W Ecuador , and through the Amazon Basin of Colombia , Venezuela , N & W Brazil , Ecuador , Peru , and Bolivia .