Noctilio albiventris Desmarest, 1818

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 : 42-44

Noctilio albiventris Desmarest

MATERIAL: 1 male (AMNH *267089); see table 9 for measurements.

IDENTIFICATION: Husson (1962, 1978), Davis (1976b), and Brosset and Charles­Dominique (1990) provided descriptions and measurements of Noctilio albiventris . Davis (1976b) recognized four subspecies in his revision: N. a. minor (southern Mexico to northwestern Venezuela), N. a. affinis (western Amazonia, northern Venezuela and the coastal Guianas), N. a. albiventris (southeastern Venezuela and southern Guyana to eastern Brazil), and N. albiventris cabrerai (southwestern Brazil, Paraguay, and northern Argentina).

According to Davis (1976b), the coastal Guianan form, N. a. affinis, is substantially larger than the nominate subspecies. Although some overlap in size was reported in length of the maxillary toothrow in both sexes and in forearm length of females (op. cit.), nonoverlapping measurements were given for forearm length in males (56.3–60.3 mm in N. a. albiventris , 61.5–70.0 mm in N. a. affinis). Unfortunately, the geographic samples closest to Paracou that Davis personally examined were from coastal Guyana (representing affinis) and near the mouth of the Amazon (representing albiventris ), leaving a wide hiatus with no representative specimens

examined (i.e., Surinam, French Guiana, and the Brazilian State of Amapa´). Based on the measurements of a Surinamese specimen reported by Husson (1962), however, Davis extended the presumed range of affinis to include the entire coastal region of the Guianas. Based on Davis’ (1976b) map (reproduced by Hood and Pitocchelli [1983] without the dots indicating collecting localities), specimens from French Guiana would presumably represent N. a. affinis.

Contrary to that expectation, our specimen from Paracou and another reported from nearby Sinnamary ( Brosset and Charles­Dominique, 1990) are morphologically intermediate to affinis and albiventris as those taxa were described by Davis (1976b). Maxillary toothrow lengths of both French Guianan specimens fall in the zone of overlap between the low end of the range of variation reported for N. a. affinis and the high end of the range of variation reported for N. a. albiventris . The forearm measurement of the female reported by Brosset and Charles­ Dominique (1990) similarly falls in the zone of subspecific overlap, while the forearm measurement of our male (table 9) fits within the gap that Davis reported between the ranges of variation of affinis and albiventris males.

Although Davis (1976b: fig. 5) mapped a discontinuity between the geographic distributions of N. a. affinus and N. a. albiventris extending across the Brazilian state of Amapa´, there is no reason to believe that this is anything but an artifact of inadequate collecting. Rainforest habitats are distributed more­or­less continuously across the eastern Guianas to the Amazon, and we suspect that Noctilio albiventris is present throughout the area. Based on the morphologically intermediate material now available from French Guiana and on the likelihood that other intergrades will be found with future collecting in Amapa´, we see no merit in continuing to recognize a subspecific distinction between the coastal Guianan and interior Amazonian populations of this species.

FIELD OBSERVATIONS: Our single specimen of Noctilio albiventris was mistnetted 1 m above the surface of a roadside puddle adjacent to well­drained primary forest.