108 Gary S. Morgan 



is wider in Nycticeius as a result of the better developed medial ridge. 

 The distal half of the posterior surface of the humeral shaft is distinctly 

 flattened in Nycticeius and the fossils, but is round in cross-section in 

 the other two species. On the distal end of the humerus, the lateral edge 

 of the articular surface (lateral epicondyle of the capitulum) extends 

 lateral to the edge of the shaft in Myotis and Pipistrellus, but is in line 

 with the shaft in the fossils and Nycticeius. Nycticeius and the fossils 

 possess a prominent notch immediately proximal to the lateral edge of 

 the capitulum that extends around the lateral edge almost to the ante- 

 rior surface of the humeral shaft. This notch is not as well developed in 

 the other two species. Finally, in Nycticeius there is a well developed, 

 rounded tubercule on the lateral edge of the shaft just proximal to the 

 notch, which is absent in P. subflavus and M. austroriparius. The region 

 medial to the medial epicondyle (trochlea) is relatively large in Myotis, 

 somewhat smaller in Pipistrellus, and very reduced in the fossils and 

 Nycticeius. Therefore, although the humeri in these three species are 

 superficially very similar, a number of characters can be used to separ- 

 ate them, and the fossils are clearly referable to N. humeralis (see mea- 

 surements on humeri in Table 2). 



Discussion. — Nycticeius humeralis is the most abundant fossil bat 

 in the Vero site, with 17 identifiable elements representing a minimum 

 of seven individuals. Evening bats roost primarily in buildings, hollow 

 trees, and under the loose bark of trees. They seem to show a preference 

 for cypress trees and are the common bat in Florida near cypress stands 

 (Jennings 1958). Like the species of Lasiurus, N. humeralis is not known 

 to enter caves, thus explaining the absence of this species from other 

 Pleistocene sites in Florida that have produced bat fossils. Apparently, 

 TV. humeralis is not as subject to raptor predation as is Lasiurus, since 

 species of the latter genus do on occasion appear in cave fossil deposits. 

 Identification of fossil cypress, Taxodium distichum, from Stratum 3 

 (Berry 1917) supports Weigel's statement (1962:42) that there was a 

 cypress pond in the vicinity of the Vero site. The presence of cypress 

 trees and the preference of Nycticeius humeralis for roosting in cypress 

 offer an explanation for the abundance of evening bat fossils at Vero. 



Family Molossidae Gill 



Tadarida brasiliensis (I. Geoffroy St. -Hilaire, 1824) 



Referred material— Stratum 3-V7219, proximal end of left humer- 

 us; Stratum unknown-V7218, nearly complete left mandible with m 2 -m 3 . 



Recent distribution. — Tadarida brasiliensis is found primarily in 

 the southern and western United States and then southward through 

 Middle America, the West Indies, and much of South America. Brazil- 



