Balantiopteryx infusca, Thomas, 1897

Bonaccorso, Frank, 2019, Emballonuridae, Handbook of the Mammals of the World – Volume 9 Bats, Barcelona: Lynx Edicions, pp. 350-373 : 365

36 . Ecuadorian Sac-winged Bat

Balantiopteryx infusca

French: Emballonure d'Équateur / German: Ecuador-Sackflügelfledermaus / Spanish: Embalonuro de sacos ecuatoriano

Taxonomy. Saccopteryx infusca Thomas, 1897 ,

“ [Rio] Cachavi, [Departamento de Esmeraldas], N[orthern] . Ecuador.”

This species is monotypic.

Distribution. Endemic to a small area of the Chocó Region on Pacific slope of o ­ lombia and Ecuador, recorded from only four localities in SW Colombia (Rio Chanco, Valle del Cauca Department) and NW Ecuador (Esmeraldas and Imbabura provinces), and presumably in appropriate habitat between these localities.

Descriptive notes. Head—body 37-42 mm, tail 12—18 mm, ear 10—14 mm, hindfoot 7-12 mm, forearm 37-9-42-4 mm; weight 4—5 g. The Ecuadorian Sac-winged Bat shows sexual dimorphism in body size, with females slightly larger as measured by forearm length (males average 38-7 mm and females 40 mm). Dorsal fur is tricolored, with blackish brown distal tips, brown hair shafts, and pale grayish brown bases. Venter is paler, with bicolored hairs having brown tips and grayish brown bases. White, wiry hairs are scattered dorsally and ventrally on many specimens. Flight membranes are black. Upper one-third of dorsal surface of uropatagium is sparsely haired, especially along short tail. Lower face is naked. Ears are oval-shaped and extend slightly above crown; interior of pinna is heavily ribbed.

Habitat. Lowland and pre-montane rainforests at elevations of 150—1200 m.

Food and Feeding. Ecuadorian Sac-winged Bats feed on small insects caught in the air.

Breeding. Adult female Ecuadorian Sac-winged Bats examined in late December in Ecuador included four lactating, two post-lactating, and five reproductively inactive individuals.

Activity patterns. The Ecuadorian Sac-winged Bat roosts in twilight zones of caves and abandoned railroad tunnels.

Movements, Home range and Social organization. Ecuadorian Sac-winged Bats roost in association with other bat species including Greater Sac-winged Bats ( Saccopteryx bilineatd ). Roosting groups of up to 40 individuals have been observed. Nine individuals of mixed sex and age were captured in mist nets at each oftwo abandoned railroad tunnels.

Status and Conservation. Classified as Vulnerable on The IUCN Red List. The Ecuadorian Sac-winged Bat has a small distribution, and populations are believed to be declining. Extent of occurrence is c. 18,551 km2 encompassing three known locations in Ecuador and one in Colombia. Habitat has been reduced by deforestation from expanding agriculture and continues to decline in extent and quality. In Ecuador, habitat is highly fragmented and faces a high risk of destruction in the near future because of uncontrolled illegal logging.

Bibliography. Alberico eta/. (2000), Albuja (1999), Alvarez (2002, 2003), Hood & Gardner (2008), McCarthy et al. (2000), Tirira (2017).

Figures

On following pages: 22. New Guinea Sheath-tailed Bat (Emballonura furati); 23. Beccari's Sheath-tailed Bat (Emballonura beccarti); 24. Large-eared Sheath-tailed Bat (Emballonura dianae); 25. Seri'sSheath-tailed Bat (Emballonura sertii); 26. Pacific Sheath-tailed Bat (Emballonura semicaudata); 27. Western Sheath-tailed Bat (Paremballonura tiavato); 28. Peters's Sheath-tailed Bat (Paremballonura atrata); 29. African Sheath-tailed Bat (Coleura afra); 30. Seychelles Sheath-tailed Bat (Coleura seychellensis); 31. Madagascar Sheath-tailed Bat (Coleura kibomalandy); 32. Dark Sheath-tailed Bat (Mosia nigrescens); 33. Chestnut Sac-winged Bat (Cormura brevirostris); 34. Gray Sac-winged Bat (Balantiopteryx plicata); 35. Thomas's Sac-winged Bat (Balantiopteryx io); 36. Ecuadorian Sac-winged Bat (Balantiopteryx infusca).

Distribution. Endemic to a small area of the Chocó Region on Pacific slope of o ­ lombia and Ecuador, recorded from only four localities in SW Colombia (Rio Chanco, Valle del Cauca Department) and NW Ecuador (Esmeraldas and Imbabura provinces), and presumably in appropriate habitat between these localities.