Vespertilionidae Author Don E. Wilson Author Russell A. Mittermeier text 2019 2019-10-31 Lynx Edicions Barcelona Handbook of the Mammals of the World – Volume 9 Bats 716 981 book chapter 56755 10.5281/zenodo.6397752 45351c32-25dd-422c-bdb2-00e73deb4943 978-84-16728-19-0 6397752 170. Humboldt’s Big-eared Brown Bat Histiotus humboldti French: Sérotine de Humboldt / German: Humboldt-GroRohrfledermaus / Spanish: Histiotus de Humboldt Taxonomy. Histiotus humboldti Handley, 1996 , “Los Venados, 4 km NNW Caracas, 10°32’N , 66°54'W , 1498 m , Distrito Federal, Venezuela .” Histiotus is phylogenetically nested within Eptesicus closely related to the New World species and some authors have included Histiotus as a subgenus of Eptesicus . Histiotus 1s recognized here as a distinct genus because of its distinct morphology, however, leaving Eptesicus paraphyletic, which may result in the splitting of Eptesicus into multiple genera. Venezuelan specimens previously reported as “ Histiotus sp. A ” by C. O. Handley, Jr. in 1976 and “ Histiotus sp. ” by A. L. Gardner in 1990 correspond to H. humboldti . It has a disjunct distribution that is probably related to a relictual wider distribution. Monotypic. Distribution. N, W & S Venezuela , NC & SW Colombia , and C Ecuador . Descriptive notes. Head-body ¢.54-59 mm, tail 47-56 mm, ear 28-32 mm, hindfoot 8-11 mm, forearm 44-49 mm; weight 9-12 g. Dorsal hairs are bicolored, with blackish bases and bright tan to brown tips; ventral hairs have fuscous bases and buff tips. Ears are very large; anterior lobe is wide, forming point at its fold; tragus is relatively short and broad. Skull is fragile; braincase and postorbital constriction region are notably inflated; rostrum is short, narrow, and shallow; zygomatic arches have strongly developed postorbital process; facial profile is sharply dished; and pterygoid processes are thin and delicate. Teeth are small and delicate, with low cusps; lower molar tooth row is relatively short. Dental formula for all species of Histiotusis12/3,C1/1,P1/2,M 3/3 (x2) = 32. Habitat. Montane regions below cloud forests and paramos and lower montane humid forests, secondary growth moist evergreen forests, scrubby tepuyan vegetation in open areas, sub-Andean woodlands, and eucalypt plantations at elevations of 1500-3000 m. Food and Feeding. Humboldt’s Big-eared Brown Bat is insectivorous. Breeding. Pregnant Humboldt’s Big-eared Brown Bats were captured between late January and early February in Colombia . Activity patterns. No information. Movements, Home range and Social organization. No information. Status and Conservation. Classified as Data Deficient on The IUCN Red List. Humboldt’s Big-eared Brown Bat is uncommon to rare in its fragmented distribution. Bibliography. Gardner (1990), Handley (1976, 1996), Handley & Gardner (2008), Rodriguez-Posada (2010), Romero (2018b), Simmons (2005), Velazco & Aguirre (2016b).