Chrotopterus auritus (Peters)

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 : 57-59

Chrotopterus auritus (Peters)

VOUCHER MATERIAL: 3 females (AMNH *267131, *267852; MNHN *1995.986) and 2 males (AMNH *267130, *267444); see table 19 for measurements.

IDENTIFICATION: Descriptions and measurements of Chrotopterus auritus can be found in Thomas (1905b), Taddei (1975a), Swanepoel and Genoways (1979), Williams and Genoways (1980a), Hall (1981), and Medellín (1989). Three subspecies were recognized by Thomas (1905b), Cabrera (1958), and Jones and Carter (1976): C. a. auritus (Mexico south to Panama and adjacent parts of northern South America), C. a. australis (southern Brazil, Paraguay, northern Argentina), and C. a. guianae (Venezuela, the Guianas, northern Brazil). However, Handley (1966) expressed doubt that these taxa could be distinguished and Koopman (1994) did not use trinomial nomenclature for Chrotop­ terus. Although Williams and Genoways (1980a) identified their Surinamese material as C. a. guianae, they did not comment on the implied validity of a subspecific classification.

7 Unfortunately, this unique capture of Lonchophylla thomasi in an elevated net is unvouchered. It is possible that the animal in question was really Lionycteris spurrelli , which somewhat resembles Lonchophylla thomasi , is known to fly in the subcanopy, and has been collected at nearby Piste St.­Élie ( Brosset and Charles­Dominique, 1990).

Thomas (1905b) distinguished Chrotopte­ rus auritus auritus , C. a. australis, and C. a. guianae on the basis of skin and pelage characters alone; no craniodental or measurement differences were noted. Characters remarked by Thomas included: (1) color of the wingtip (dark in auritus , small white tip in australis, broad white tip in guianae); (2) color of the distal phalanges of digit III of wing (dark in australis, distalmost phalanx white in australis, two distal phalanges white in guianae); (3) color of the membranous edge between wing digits IV and V (dark in auritus and australis, trace of white along edge in guianae); (4) distinct metacarpal patch of woolly fur at the base of the thumb (present in australis, absent in guianae, not mentioned for auritus ); and (5) extension of body fur onto the flight membranes (fur extending onto the ventral surface of the wing membrane behind the elbow and onto the dorsal surface of the interfemoral membrane in australis, no fur extending onto membranes in guianae, not mentioned for auritus ).

Our Paracou specimens of Chrotopterus auritus correspond to previous qualitative and morphometric descriptions of the species. However, our material exhibits external character variation that does not conform with any of Thomas’ (1905b) subspecific diagnoses. For example, the Paracou specimens have a small white wingtip (supposedly characteristic of C. a. australis), the two dis­ tal phalanges of wing digit III are white (supposedly characteristic of C. a. guianae), the edge of the wing membrane between the fourth and fifth digits is dark in one specimen (supposedly characterisic of C. a. auritus and C. a. australis) and white (supposedly characteristic of C. a. guianae) in others, there is a distinct metacarpal patch of woolly fur at the base of the thumb (supposedly characteristic of C. a. australis), the body fur extends onto the ventral surface of the wing membrane behind the elbow (supposedly characteristic of C. a. australis), but the body fur does not extend onto the dorsal surface of the interfemoral membrane (supposedly characterisic of C. a. guianae). We therefore agree with Handley (1966) and Koopman (1994) that a subspecific classification of C. auritus is not currently useful.

FIELD OBSERVATIONS: All five of the Chrotopterus auritus we collected at Paracou were taken in ground­level mistnets; four were captured in well­drained primary forest and one in creekside primary forest. Three individuals were captured singly (on different nights), but an adult male and an adult female, presumably travelling together, were captured in the same net within seconds of one another on 22 July 1993.