Bats of Texas

Accounts of Species

Accounts of Species 76 family mormoopidae across the forehead. Mormoops is readily recognized by its distinctive facial ornamentations , sharply upturned rostrum, and tail. Numerous tubercles and folds cover the rostrum and lips, and the ears are shaped and connected in such a way that the animal’s mouth, when opened, functions as an orifice at the bottom of this funnel-shaped group of structures . The tail protrudes dorsally from the interfemoral membrane with approximately 1.3 cm not attached to this membrane and lying above it. The long forearm is strongly curved. The skull is markedly shortened, and the cranium is high and domed. Dental formula: I 2/2, C 1/1, Pm 2/3, M 3/3 × 2 = 34. Average external measurements are as follows: total length, 90 mm; tail, 26 mm; hind foot, 10 mm; ear, 13 mm; length of forearm , 54 mm. Weight: 13–19 g. Distribution. In Texas this bat is known from the Chihuahuan Desert region (Trans-Pecos), southern edge of the Edwards Plateau, and Gulf Coastal Plains. It typically is found in lowland areas (below 3,000 m in elevation; Rezsutek and Cameron 1993), especially desert scrub and riverine habitats, as at Big Bend Ranch, although it also has been captured in the mountainous country of the Apache, Chisos, Chinati, Davis, and Elephant mountains and in the Sierra Vieja range. It is a common winter (November 1 to March 15) resident of caves along the extreme southern edge of the Edwards Plateau, where it apparently reaches its northern distributional limits in the United States. However, its occurrence at specific localities is highly variable and unpredictable. Family Mormoopidae Ten species of New World bats make up the family Mormoopidae, which includes the mustached, naked-backed, and ghostfaced bats, which are variously distributed from the southern United States through Mexico, Central America, and South America to southern Brazil. Characterized by fleshy appendages on the snout and chin and a short tail protruding dorsally from the interfemoral membrane, these bats are abundant in the tropics as well as semiarid and subtropical environments. The only species of this family to occur in the United States is the ghost-faced bat, Mormoops megalophylla, which has been recorded in Texas and Arizona. Mormoops megalophylla Peters, 1864 Ghost-Faced Bat Etymology. The generic name Mormoops comes from Greek mythology, the first part of which, mormo, means “ghost,” “bugbear,” “hobgoblin,” or “she-monster,” a female vampirelike creature or spirit that bit children (Rezsutek and Cameron 1993). The second part, ops, translates as “face.” The specific name also is Greek, from the words megas and phyllon, and means “big or great leaf” (Stangl et al. 1993). Subspecies. Texas specimens are referable to the subspecies M. m. megalophylla Peters, 1864, as indicated by the most recent taxonomic revision of the species (Smith 1972). Description. This is a relatively large (forearm = 51–59 mm) bat with reddishbrown to dark brown pelage. The fur becomes increasingly reddish with age. The ears are large and rounded and join ghost-faced bat 77 sonal migration between the 2 regions, although such movements have yet to be substantiated. Life History. Ghost-faced bats typically roost in caves, tunnels, and mine shafts, but they also have been found in old buildings. In addition to the caves listed earlier, these bats have been taken in a railroad tunnel near Comstock in Val Verde County. Specimens also have been captured in January and February in the junior high school at Edinburg in Hidalgo County. Students found them hanging from the rough plaster ceiling in one of the halls. Although they may congregate in large numbers at a roosting site (as many as 500,000 individuals; Barbour and Davis 1969), these bats do not form the Mormoops has been collected or observed at Frio Cave (Uvalde County), Webb Cave (Kinney County), Valdina Farms Sinkhole (Medina County), Sorcerer’s Cave (Terrell County), and Haby, Ney, and Rattlesnake Caves (Bexar County) in January, February, March, May, September, November, and December , indicating that it uses the Edwards Plateau caves as a winter retreat (Eads et al. 1957a). Many apparently suitable caves near those just listed are not used, although they are occupied by bats often associated with Mormoops (Raun and Baker 1958). In contrast to the winter records from the Edwards Plateau, those from the Trans-Pecos are from the warmer months of the year (March 16 to October 31). This...