Artibeus (Artibeus) obscurus (Schinz)

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 : 102-104

Artibeus (Artibeus) obscurus (Schinz)

VOUCHER MATERIAL: 27 females (AMNH *266271, *266273, *266279, *266281, *266287, *267997, *268000, *268501, *268516, *268518, *268520, 268522, *268523, *268524, *268525, *268526, *268527; MNHN *1995.1160, *1995.1161, *1995.1162, *1995.1163, *1995.1164, *1995.1165, *1995.1166, *1995.1167, *1995.1168, *1995.1169) and 10 males (AMNH *266272, *266286, *266288, *267208, *267210, *268517, 268519; MNHN *1995.1170, *1995.1171, *1995.1172); see table 38 for measurements.

IDENTIFICATION: We follow Handley (1989) in using the name Artibeus obscurus instead of A. fuliginosus for the smallest and darkest member of the subgenus Artibeus found throughout the wet South American lowlands east of the Andes. Artibeus obscurus is best identified by reference to Handley (1987, 1989), Lim and Wilson (1993), and Marques­ Aguiar (1994). Additional descriptions and comparative measurements can also be found (under the name A. fuliginosus ) in Swanepoel and Genoways (1979), Koepcke and Kraft (1984), and Brosset and Charles­Dominique (1990). No subspecies are currently recognized (Handley, 1987, 1989; Marques­ Aguiar, 1994).

Although our voucher material generally agrees with previous qualitative descriptions of Artibeus obscurus , three of our specimens lack M3 completely, a polymorphism noted by Handley (1989) and Marques­Aguiar (1994), but not by Handley (1987) or Lim and Wilson (1993). Measurements of the Paracou series likewise fall within the known range of variation for this species with the exception of our largest specimens, which have slightly longer forearms than previously reported.

FIELD OBSERVATIONS: We recorded 117 captures (probably including some recaptures) of Artibeus obscurus at Paracou, of which 104 were in ground­level mistnets, 7 were in elevated mistnets, and 6 were at roosts. Of the 104 ground­level mistnet captures, 42 were in well­drained primary forest, 37 were in swampy primary forest, 19 were in creekside primary forest, 4 were in manmade clearings, 1 was in closed­canopy secondary growth, and 1 was over a roadside puddle. Of the seven elevated mistnet captures, five were made between 7 and 20 m above a narrow dirt road, one was 10 m above a treefall in well­drained primary forest, and one was 5–8 m above the ground in the subcanopy of swampy primary forest.

We found three roosting groups of Artibeus obscurus under exfoliating pieces of bark 6–7 m above the ground on the trunks of grignon trees, Ocotea rubra (Lauraceae) , in well­drained primary forest (fig. 40). One of these groups consisted of an adult female with a nursing juvenile; another consisted of an adult female, a nursing juvenile, and an escaped adult of unknown sex; and the third was a solitary near­term pregnant female. We also found a solitary adult male Artibeus obscurus roosting beneath an unmodified leaf of Phenakospermum guyannense (Strelitziaceae) about 4 m above the ground at the edge of a clearing in secondary vegetation.