126 Joseph Travis 



40. Tail musculature distinctly bicolored; fins without stripe; larger specimens have 



prominent black edging around a clear or speckled fin Rana heckscheri 



Tail musculature distinctly striped; stripe or row of dots (formed by pigment 

 around the lateral line pores) present on dorsal fin; no black edging on tail 



fins Rana virgatipes 



41. A-2 gap ratio greater than 0.50; body and tail patterned with distinct black dots; 



belly light green, white, or yellow in life Rana catesbeiana 



A-2 gap ratio less than 0.50; body and tail lacking distinct black dots; belly of 

 larger individuals is cream or white in life Rana clamitans 



NOTES ON FIELD IDENTIFICATION 



Many animals can be diagnosed to genus or species in the field with 

 the use of a hand lens. Small tadpoles are always difficult to identify, 

 but the following notes should allow larger individuals to be placed into 

 one of five principal groups. 



Hylidae: body square in dorsal view, eyes lateral; nostrils small com- 

 pared to eyes; dextral anus; oral disc not emarginate; 

 never black in color, but can range from bluish to brown. 



Rana: body oval or round in dorsal view, eyes dorsal or dorsolateral; 

 nostrils small compared to eyes; dextral anus; oral disc 

 emarginate; color diagnostically unreliable. 



Bufo: body round or oval in dorsal view, eyes dorsal and with a "cross- 

 eyed" aspect; nostrils large, and head appears to have a 

 "snout"; median anus; oral disc emarginate; color may be 

 dark or light (Bufo quercicus). 



Scaphiopus holbrooki: body round or oval in dorsal view, eyes close- 

 set and dorsal; head wide relative to body width; entire 

 body moves from side to side while swimming; median 

 anus; oral disc not emarginate; color black. 



Gastrophryne carolinensis: body round in dorsal view, distinctly de- 

 pressed; eyes wide-set and lateral; median anus; no oral 

 disc; color dark, although larger individuals have mottled 

 venters and a stripe on the tail musculature. 



ACKNOWLEDGMENTS.— Many people helped collect tadpoles, 

 but I owe a particular debt of gratitude to Mr. Jack Longino, Mr. Peter 

 Morin, and Dr. Henry Wilbur. Professor Joseph Bailey allowed me to 

 use the Duke Vertebrate Collection, and Alvin Braswell, North Carolina 

 State Museum of Natural History, graciously provided specimens of 

 preserved tadpoles. Professor Henry Wilbur generously provided me 

 with the time, funding, and encouragement to construct this key and to 

 refine it from 1977 to 1980 while I was at Duke University. Drs. Ronald 



