Thyroptera tricolor Spix, 1823

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 : 130-134

Thyroptera tricolor Spix

VOUCHER MATERIAL: 16 females (AMNH *266348, *266356, *266358, 266359, *266364, *267215, *267216, *267217, *267218, *268576; MNHN *1995.874, *1995.875, *1995.876, *1995.877, 1995.878, *1995.879) and 12 males (AMNH *266352, 266355, 266357, *266361, *266363, 266365, *268574, 268577; MNHN 1995.880, *1995.881, 1995.882, 1995.883); see table 50 for measurements.

IDENTIFICATION: We consulted the descriptions and measurements of Thypotera tricol­ or provided by Husson (1962, 1978), Brosset and Charles­Dominique (1990), and Pine (1993) to confirm the identification of our material. Although three subspecies were recognized by Wilson and Findley (1977) and Koopman (1994), the morphological justification for a trinomial classification is not clear. Furthermore, Pine (1993) suggested that some published observations of geographic variation within T. tricolor may have been based on material that was not correctly identified to species. Pending a thorough review of the problem, it currently seems pointless to employ subspecific nomenclature.

Our material from Paracou conforms with published descriptions of Thyroptera tricolor in all respects. Although Pine (1993) noted some variation in the number of lappets on the calcar in some populations of this species, all of our specimens have two lappets on the calcar. The free portion of the tail is relatively long in all our fluid­preserved material, which conforms to Pine’s (1993) ob­ servations. We note, however, that the free portion of the tail appears quite short in our skins, an artifact that resulted from pinning the specimens to dry with the uropatagium maximally extended.

The size range documented by our vouch­ er specimens (table 50) is somewhat greater than that previously reported from Surinamese and French Guianan populations of Thyroptera tricolor by Husson (1962, 1978) and Brosset and Charles­Dominique (1990). In addition, the Paracou measurement data suggest some slight sexual dimorphism, with females exceeding males in average body weight and total length.

FIELD OBSERVATIONS: We recorded 40 captures (possibly including some recaptures) of Thyroptera tricolor at Paracou, of which 3 were in ground­level mistnets, 1 was in an elevated net, and 36 were at roosts. One ground­level mistnet capture was in welldrained primary forest, one was in swampy primary forest, and one was in a manmade clearing. Our single elevated mistnet capture was made at 7–8 m above the ground in the subcanopy of swampy primary forest.

We found 12 roosting groups of Thyroptera tricolor , all of them in foliage (table 51). Most (nine) roosts were in the erect, halfunrolled new leaves of heliconias, Heliconia sp. ( Heliconiaceae ) (fig. 53), or Phenakospermum guyannense (Strelitziaceae) , but three roosting groups occupied scrolled dead leaves hanging from large Phenakospermum plants (fig. 54). Of the five Heliconia roosts we found, one was in well­drained primary forest, two were in swampy primary forest, and two were in creekside primary forest. Five Phenakospermum roosts were in secondary vegetation (especially along the margins of a small savanna enclave) and two were in wet glades surrounded by swampy primary forest. All of the leaves that we found used by T. tricolor as roosts were shaded; none was in direct sunlight. The number of bats per roost varied from one to six with a well­defined mode of four. We did not record more than a single adult male in any roost.