106 Gary S. Morgan 



humeri of these two species are broadly overlapping in size (see mea- 

 surements, Table 2). Examination of a series of humeri of Recent L. 

 borealis and L. seminolus from Alachua County, Florida revealed no 

 reliable morphological characters that would distinguish them. These 

 species are also very similar in external and cranial morphology. They 

 can, however, be separated by pelage color and the presence of a lach- 

 rymal ridge in L. borealis. Unfortunately, fossils cannot be definitely 

 assigned to one species or the other without a skull. 



Lasiurus borealis occurs primarily in the northern half of the Flor- 

 ida peninsula, having been recorded as far south as Hardee County, 

 although it is not common south of Pasco County. Lasiurus seminolus 

 occurs sympatrically with L. borealis throughout most of north Florida; 

 however, the Seminole bat is more widely distributed in the southern 

 half of the peninsula and is the only small Lasiurus presently found on 

 the east coast of Florida as far south as Indian River County. Because 

 the mammalian fauna from Stratum 3 at Vero closely approximates the 

 Recent fauna of that vicinity, these fossils are tentatively referred to L. 

 seminolus. 



Discussion. — Like L. intermedius, L. seminolus roosts primarily in 

 clumps of Spanish moss hanging from trees. Although L. borealis is not 

 necessarily associated with Spanish moss, it too roosts almost exclu- 

 sively in trees. The tree-roosting habits of these two small species 

 undoubtedly account for their rarity in the fossil record. The occurrence 

 of L. borealis or L. seminolus in the Reddick site is probably a result of 

 Barn Owl predation, while the presence of L. seminolus at Vero is most 

 likely related to their preference for feeding near water. Although only 

 four fossils referable to L. seminolus were identified from Vero, three of 

 these were proximal ends of right humeri representing a minimum of 

 three individuals. 



The proximal half of a right humerus (V7205), identified as Myotis 

 sp. by Weigel (1962:32) and later referred to M. austroriparius by Webb 

 (1974:14), is actually referable to Lasiurus cf. seminolus. The fossil 

 differs from Myotis and agrees with the smaller species of Lasiurus in its 

 larger size, elliptical humeral head oriented at a 45° angle to the shaft, 

 and the reduced lesser tuberosity. The left humerus (V7204) referred to 

 Lasiurus sp. by Weigel (1962:32) and later to L. borealis by Webb 

 (1974:14) is a right humerus instead. I could not locate the left femur 

 from Stratum 3 identified as Lasiurus sp. by Weigel. 



Nycticeius humeralis (Rafinesque, 1818) 

 Referred material— Stratum 2-V7228, nearly complete right 

 mandible with m 2 -m 3 ; V721 1, nearly complete right humerus; Stratum 3- 

 V7229, partial edentulous right mandible; V7209, complete right humer- 



