100 Gary S. Morgan 



postcranial material, even though limb elements are often quite abund- 

 ant in sites where bat fossils occur. In fact, two of the bat species identi- 

 fied from Vero are based only on postcranial material. The classic study 

 of Miller (1907) used characters of the humerus, in addition to more 

 conventional cranial and dental characters, to diagnose many of the 

 higher taxonomic groups of bats. In her work on the fossil bats from 

 the Miocene Thomas Farm Site in northern Florida, Lawrence (1943) 

 discussed the taxonomic importance of the humerus in bats, demon- 

 strating that almost all Recent genera of North American vespertilionids 

 could be distinguished using characters of the proximal and distal ends 

 of the humerus. The radius, especially the proximal end, is useful in 

 distinguishing between certain groups of bats, although it lacks the large 

 number of diagnostic characters found in the humerus. Terminology for 

 various structures on the humerus and proximal end of the radius fol- 

 lows Vaughan (1959) and Smith (1972). Miller (1907) and Lawrence 

 (1943) used the terms trochiter and trochin for the greater and lesser 

 tuberosity of the humerus, respectively. However, since these structures 

 are homologous with the greater and lesser tuberosity of other mam- 

 mals, the latter terms will be used in this paper. Dental terminology is 

 standard for mammals (Szalay 1969). Site names followed by Roman 

 numerals refer to fossil sites listed in the Florida State Museum verte- 

 brate paleontology locality files. Cranial and dental measurements were 

 taken with a Gaertner measuring microscope accurate to 0.01 mm. 

 Postcranial measurements were taken with dial calipers accurate to 0.10 

 mm. 



All recent comparative material is from the Mammal Collection of 

 the Florida State Museum, University of Florida (UF). The Vero fossils 

 are from the Florida Geological Survey Collection, formerly housed in 

 Tallahassee and now merged with the Florida State Museum Fossil Ver- 

 tebrate Collection in Gainesville (UF/FGS, catalogue number preceded 

 byV). 



SYSTEMATIC PALEONTOLOGY 



Order Chiroptera Blumenbach 



Family Vespertilionidae Gray 



Eptesicus fuscus (Palisot de Beauvois, 1796) 



Referred material— Stratum 2-V7200, partial left mandible with 

 m 3 ; Stratum unknown-V7201, complete edentulous left mandible. 



Recent distribution.— Eptesicus fuscus is one of the most wide- 

 spread bats in the New World. It occurs throughout the United States, 

 southern Canada, Greater Antilles, Bahamas, Middle America, and 

 northern South America. In Florida, the big brown bat has been 



