Rhogeessa minutilla, G. S. Miller, 1897

Don E. Wilson & Russell A. Mittermeier, 2019, Vespertilionidae, Handbook of the Mammals of the World – Volume 9 Bats, Barcelona: Lynx Edicions, pp. 716-981 : 858

211.

Tiny Yellow Bat

Rhogeessa minutilla

French: Rhogeessa de Miller / German: Winzige Gelbfledermaus / Spanish: Rogesa de Miller

Other common names: Little Desert Bat

Taxonomy. Rhogeessa minutilla G. S. Miller, 1897 ,

“Margarita Island, Venezuela.”

Previously considered a race of R. parvula , based on external and skull morphology; returned to species level based on bacular, external and skull morphology. Race cautiva resembles nominate in coloration, but is larger in measurements and body mass (where it resembles R. tumida ); it has been speculated that it might be a separate species. Two subspecies recognized.

Subspecies and Distribution. R.m.minutillaG.S.Miller,1897—GuajiraPeninsulaofColombiaandVenezuelaStoCaquetaandCaucadepartmentsinWColombia,andelsewhereinVenezuelaNofMéridaState,includingMargaritaI.

R. m. cautiva Soriano, Naranjo & Farinas, 2004 — isolated population in xeric intermontane basin of rivers Chama and Nuestra Senora, Mérida State, NW Venezuela.

Descriptive notes. Head-body ¢. 42-43 mm, tail 28-34 mm, ear 11-14 mm, hindfoot 4-7 mm, forearm 25-5-29- 5 mm; weight 2:7-4- 3 g. Dorsal fur is bicolored, with light buff bases and cinnamon-buff to sedan-brown tips; ventral fur warm buff to light ocherous-buff to cinnamon-buff. Ears small and rounded; tragus long. Wing membranes blackish, thick, and strong; uropatagium naked. Skull small and delicate (greatest skull length 11:5-12- 5 mm); braincase small and rounded, elevated posteriorly; rostrum long and narrow; zygomatic arches slender and spread wide; interorbital region is relatively narrow. I” is simple; lower incisors bifid with obsolete outer lobes; lingual cingulum of C' has two small cusps, differing from congeners, which have smooth canines; I, has smaller cusps than I, and is about same size or slightly smaller than L.

Habitat. Coastal and insular regions, arid desert scrub, thorn forest, and xeric thornshrub forests; one capture in a mangrove swamp. Recorded from sea level up to 900 m.

Food and Feeding. Insectivorous, feeding mainly on small aerial insects that are captured in open areas. The species preys mainly on soft-bodied insects, which make up almost 90% ofits diet. Diptera , Hymenoptera , Lepidoptera , and Coleoptera correspond to 85% of the diet by frequency.

Breeding. The species is seasonally monoestrous, with single reproductive peak per year during rainy season. Pregnant females were captured from February to May, and lactating females from June to September. Juveniles were found from late June to September.

Activity patterns. Nocturnal, appearing immediately after sunset; most captures occur in first hour after sunset. The species has been found roosting in hollow columnar cacti.

Movements, Home range and Social organization. Generally forms small colonies.

Status and Conservation. Classified as Vulnerable on The IUCN Red List. Found in scattered locations across its range, but is locally common. Populations are decreasing, with a decline of more than 30% overthe last three generations. Its habitat is also declining. Part ofits range is included in protected areas. The greatest causes of habitat loss and population fragmentation are industrial, commercial, and residential develpoments along coastal and insular regions of Venezuela, and into the eastern Andes.

Bibliography. Allen (1902), Bickham & Ruedas (2008), Genoways & Baker (1996b), Goodwin (1958b), Goodwin & Greenhall (1961), LaVal (1973a), Linares (1998), Ruedas & Bickham (1992), Simmons (2005), Solari (2016e), Soriano et al. (2004), Sosa et al. (1996).

Figures

202. Canyon Bat (Parastrellus hesperus), 203. Tricolored Bat (Perimyotis subflavus), 204. Van Gelder’s Bat (Bauerus dubiaquercus), 205. Pallid Bat (Antrozous pallidus), 206. Black-winged Little Yellow Bat (Rhogeessa tumida), 207. Yucatan Yellow Bat (Rhogeessa aenea), 208. Bickham’s Yellow Bat (Rhogeessa bickhami), 209. Menchu’s Yellow Bat (Rhogeessa menchuae), 210. Ecuadorian Little Yellow Bat (Rhogeessa velilla), 211. Tiny Yellow Bat (Rhogeessa minutilla), 212. Genoways’s Yellow Bat (Rhogeessa genowaysi), 213. Thomas's Yellow Bat (Rhogeessa io), 214. Northern Little Yellow Bat (Rhogeessa parvula), 215. Least Yellow Bat (Rhogeessa mira), 216. Allen’s Yellow Bat (Rhogeessa alleni), 217. Slender Yellow Bat (Rhogeessa gracilis), 218. Husson’s Yellow Bat (Rhogeessa hussoni), 219. Western Barbastelle (Barbastella barbastellus), 220. Caspian Barbastelle (Barbastella caspica), 221. Arabian Barbastelle (Barbastella leucomelas), 222. Eastern Barbastelle (Barbastella darjelingensis), 223. Japanese Barbastelle (Barbastella pacifica), 224. Beijing Barbastelle (Barbastella beijingensis)

Subspecies and Distribution. R.m.minutillaG.S.Miller,1897—GuajiraPeninsulaofColombiaandVenezuelaStoCaquetaandCaucadepartmentsinWColombia,andelsewhereinVenezuelaNofMéridaState,includingMargaritaI. R. m. cautiva Soriano, Naranjo & Farinas, 2004 — isolated population in xeric intermontane basin of rivers Chama and Nuestra Senora, Mérida State, NW Venezuela .