Fossil Bats 109 



ian free-tailed bats occur throughout Florida, and according to Layne 

 (1974) the species is the most successful bat in southern Florida, where 

 it has been recorded as far south as Dade and Collier counties. 



Fossil record. — Tadarida brasiliensis is known from three other 

 fossil sites in eastern North America, two in Florida (Reddick IA and 

 Nichol's Hammock) and the other in Mammoth Cave, Kentucky (out- 

 side the present range of the species). There are numerous Pleistocene 

 records of T. brasiliensis from the southwestern United States and the 

 West Indies. 



Description and comparisons. — The mandible referred to T. brasil- 

 iensis is distinguishable from Eumops by its considerably smaller size 

 and from Pipistrellus by its considerably larger size. The fossil differs 

 from Lasiurus, Eptesicus, Nycticeius, Myotis, and Plecotus in the 

 reduced coronoid process, shallow masseteric fossa, small compressed 

 incisors, double-rooted p3, and larger ni3 relative to m2. Myotis and 

 Plecotus both have the same number of premolar alveoli as Tadarida, 

 but they possess single-rooted P2 and p3, while Tadarida lacks p2 and 

 has a double-rooted p3. Based on the above combination of characters, 

 the fossil mandible is readily identified as T. brasiliensis (see measure- 

 ments, Table 1). 



Although poorly preserved and lacking the lesser tuberosity, the 

 proximal humerus here referred to T brasiliensis is identifiable. Based 

 on its small size and elliptical humeral head, the humerus can be distin- 

 guished from that of all Florida bats except the two small species of 

 Lasiurus and Tadarida. The humerus is identified as T brasiliensis by 

 its broader and shorter pectoral ridge and greater distal extension of the 

 medial ridge. 



Discussion. — Only two fossils of T. brasiliensis, probably represent- 

 ing a single individual, have been identified from Vero. The Brazilian 

 free-tailed bat is rare as a fossil in Florida, having been recorded from 

 only three sites based on less than ten specimens. At the present time, T. 

 brasiliensis in Florida roosts almost exclusively in man-made structures, 

 such as in houses and under bridges (Jennings 1958). Although it has 

 been observed in small numbers in several caves in Marion County, 

 Florida (R. Franz, pers. comm.), these probably do not represent roost- 

 ing colonies. In marked contrast to the southwest, where T. brasiliensis 

 inhabits caves in colonies sometimes numbering into the millions, it is 

 not known to roost in caves in the southeastern United States. Appar- 

 ently, the warm humid atmosphere of Florida caves offers an unsuitable 

 environment for roosting colonies (Jennings 1958). Tadarida brasiliensis 

 in Florida has also been observed roosting under the dead fronds of 

 palm trees in Lee and Charlotte counties in southwestern Florida, and 

 in hollow mangrove trees in the Tampa Bay area (Jennings 1958). Palm 



