Cormura brevirostris (Wagner)

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 : 24-28

Cormura brevirostris (Wagner)

VOUCHER MATERIAL: 17 females (AMNH *266009, *267070, 267076, *267078, *267389, *267391, *267823, *267824, *267825, *267826, *267828; MNHN *1995.823, *1995.824, *1995.825, *1995.826, *1995.833, *1995.834) and 18 males (AMNH *265994, *266002, *266003, *267069, *267071, *267074, *267075, 267079, *267390, *267394, *267822, *267827; MNHN *1995.827, *1995.828, 1995.829, *1995.830, *1995.831, *1995.832); see table 1 for measurements.

IDENTIFICATION: Cormura brevirostris can be distinguished easily from other emballonurids by the unique location of the antebrachial wing sac (Sanborn, 1937: fig. 37; Jones and Hood, 1993: fig. 1). Craniodental characters and measurements of C. brevirostris from the Guianas and other parts of South America were discussed by Sanborn (1937), Husson (1962, 1978), Brosset and Charles­ Dominique (1990), and Jones and Hood (1993). Husson (1962) provided a revised description of Cormura and a detailed discussion of Myopteryx pullus , which he and all subsequent authors have considered to be a junior synonym of C. brevirostris . No subspecies are currently recognized ( Jones and Hood, 1993; Koopman, 1994).

Our specimens from Paracou conform to previous descriptions of Cormura brevirostris and fall within the range of size variation previously documented in Surinam and French Guiana.

FIELD OBSERVATIONS: We recorded 42 captures (possibly including some recaptures) of Cormura brevirostris at Paracou: 7 in ground­level mistnets, 12 in elevated mistnets, and 23 at roosts. Of the seven groundlevel mistnet captures, one was in welldrained primary forest, three were in creekside primary forest, two were in a treefall opening in creekside primary forest, and one was in a manmade clearing. Eight elevatednet captures were between 10 and 21 m above a narrow dirt road, and four were made between 10 and 38 m over a treefall gap in well­drained primary forest.

We encountered 10 different roosting groups of Cormura brevirostris at eight unique roost sites (one site was revisited twice). Five roost sites were on the dark undersides of fallen trees (e.g., fig. 14), but one roosting group was found clinging to an unmodified leaf of Phenakospermum guyannensis (fig. 15), another occupied a shallow cavity in the base of a living tree suspended by its roots over a stream, and another was found under a concrete bridge. In addition to the bridge roost, two natural roosts (both in primary forest) were over small streams, but five others (four in primary forest and one in secondary forest) were far from water.

The 10 roosting groups of Cormura brevirostris we found at Paracou (table 2) consisted of two to five individuals, with a modal group size of three. Whereas three roosts each contained two adult males, we never found more than one adult female per roost. In all eight roosting groups that we were able to observe closely before the bats were disturbed, the animals were clustered together in a compact mass; in four groups we were able to see that the individuals were actually touching one another back­to­belly. Although three species of Peropteryx ( P. kappleri , P. leucoptera , and P. macrotis ) previously or subsequently occupied some of the same roosts where we captured C. brevirostris , we never found more than one of these (or any other emballonurid species) sharing the same roost simultaneously.