Fossil Bats 99 



Weills and Ayers. According to Weigel, the beds appeared to be dis- 

 turbed at Locality 1. A small creek flowed through this locality, appar- 

 ently cutting through Strata 2 and 3 and mixing fossils from these beds 

 with more recent artifacts and human bone. In six other stratigraphic 

 sections at Vero, Weigel found no extinct vertebrates in Stratum 3 and 

 no evidence of stream channel fills or other reworked deposits. 



Owing to the presence of human remains at Vero, the age of the 

 various strata there has raised much controversy. Weigel (1962:8-9) gave 

 five radiocarbon dates for Stratum 2, ranging in age from 3,550 years 

 before present (ybp) to greater than 30,000 ybp. Based on a radiocarbon 

 date from the top of Stratum 2, Weigel (1962) hypothesized that now 

 extinct vertebrates may have persisted in Florida until 3,500 years ago. 

 In retrospect, it appears clear that this date is erroneous, as recent stud- 

 ies based on extensive series of radiocarbon dates (Meltzer and Mead 

 1983) suggest that no members of the extinct Pleistocene megafauna 

 survived in North America beyond 10,000 ybp. Although no radiocar- 

 bon dates are available from Stratum 3, the absence of extinct Pleisto- 

 cene megafauna and the predominance of species found in the imme- 

 diate vicinity at the present time, indicate that this part of the fauna is 

 Holocene in age. Holocene faunas are uncommon in Florida, or at least 

 they have rarely been recognized and studied. The late Pleistocene and 

 early Holocene Devil's Den fauna (Martin and Webb 1974), and the 

 Nichol's Hammock fauna (Hirschfeld 1968) of unknown but probably 

 late Holocene age, are the best known. In this paper, vertebrate fossils 

 from Stratum 2 are regarded as late Wisconsinan (late Pleistocene, 

 Rancholabrean), while fossils from Stratum 3, in particular the ex- 

 tremely rich microvertebrate sample from Weigel's Site 3a, are consi- 

 dered Holocene. Only four bat fossils were recovered from Stratum 2 in 

 Weigel's excavations, the mandible he referred to Eptesicus sp. and 

 three specimens of Nycticeius humeralis. All six species identified from 

 Vero are present in Stratum 3, where the great majority of the bat 

 remains occur. 



METHODS AND MATERIALS 



Skulls and postcranial skeletons of all 1 1 species of Recent bats 

 native to Florida were available for comparison with the fossil material 

 from Vero. Where possible, specimens from localities in southern Flor- 

 ida were used for comparisons. Only one maxillary fragment is present 

 among the Vero chiropteran fossils, while mandibles are slightly more 

 common. The most important mandibular characters used in differen- 

 tiating the various species were overall size, number and form of the 

 premolars, morphology of the molars, length of the ramus, shape of the 

 coronoid process, and development of the masseteric fossa. Very few 

 previous studies of bats from Florida Pleistocene localities have included 



