Furipterus horrens (F. Cuvier)

Simmons, Nancy B. & Voss, Robert S., 1998, The mammals of Paracou, French Guiana, a Neotropical lowland rainforest fauna. Part 1, Bats, Bulletin of the American Museum of Natural History 237, pp. 1-219 : 129

Furipterus horrens (F. Cuvier)

VOUCHER MATERIAL: 9 females (AMNH *265975, *265979, 265980, *267213, *267214, *268572, 268573; MNHN *1995.870, *1995.871) and 4 males (AMNH *267212, *267507; MNHN *1995.872, 1995.873); see table 49 for measurements.

IDENTIFICATION: Husson (1962, 1978) provided a detailed description and measurements of Furipterus horrens , and additional morphometric data were published by Brosset and Charles­Dominique (1990). No subspecies are recognized (Koopman, 1994).

Although our voucher material does not differ in any respect from Husson’s (1962, 1978) careful qualitative description of Furipterus horrens , measurements of the Paracou series document a greater range of size variation than that previously reported from the Guianas. Our measurement data (table 49) additionally suggest that the species may be sexually dimorphic (females averaging slightly larger than males in most dimensions), an observation that tends to corroborate Uieda et al.’ s (1980) report of sexual dimorphism in a northeastern Brazilian population. In her otherwise excellent external descriptions of Furipterus horrens, Emmons stated that the thumb has ‘‘no claw’’ (1990: 82) or ‘‘almost no claw’’ (1997: 91). The thumb, small and enclosed in the wing membrane, bears a tiny but distinct claw in all the specimens we examined. FIELD OBSERVATIONS: We collected 13

specimens of Furipterus horrens at Paracou, of which 12 were taken at roosts and 1 was shot as it flew back and forth along a regular beat about a meter above the ground in welldrained primary forest at night. The nine roosting groups we found consisted of one to two individuals, either solitary adults (of both sexes) or lactating females with nursing juveniles. In no case did we find more than one adult occupying a roost. All of the roosts we found were in or under fallen trees in various stages of decomposition. One roost was a small cavity in the broken end of a rotting log (fig. 52), but most were on the undersides of trunks or in dark chambers between buttresses (fig. 17). Four roosts were in well­drained primary forest, one was in swampy primary forest, two were in primary forest of unrecorded character, one was in selectively logged forest, and one was in closed­canopy secondary growth. Small, dark, solitary bats that flew away unidentified from refugia in or under woody debris on many occasions throughout the course of our fieldwork at Paracou were probably F. horrens . Although we never caught this species in mistnets, our impression was that roosts of F. horrens could be found by careful searching almost anywhere in the forest.