INTRODUCTION 
Many amphibians and reptiles dispersed between North and 
South America along the Isthmus of Panama during the "Great 
American Biotic Interchange," after the Pliocene closure of the 
isthmian gap. The results of nterchanges before the gap formed 
are also in evidence today, but involve fewer species (Vanzolini 
and Heyer, 1990). Panama's herpetological significance goes 
beyond being a land bridge between continents, however. The 
country has distributional continuities with North, Middle and 
South America, and border to border from both directions. The 
country also has a significant number of endemics (14 percent of 
the amphibians; 7 percent of the reptiles; 10 percent overall). 
With an area of only 77,082 km 2 , about half (50.8%) the size of 
Florida, Panama has approximately 2.8 times more native 
amphibians and reptiles than Florida, 5.7 times expectation based 
on area alone. 
There is no published checklist and bibliography for just 
the herpetofauna of Panama. Partial lists are available: Dunn, 
1931a and b; Myers and Rand, 1969; Rand and Myers, 1990; and 
Smith, 1958. Peters and Orejas-Miranda (1970), Peters and Donoso- 
Barros (1970), and Vanzolini (1986) cover a much larger area for 
the snakes and lizards. Campbell and Lamar (1989) have done the 
same for the poisonous snakes, Iverson (1992) for turtles, King 
and Burke (1989) for turtles and crocodilians, Frost (1985) for 
amphibians, and Villa, Wilson, and Johnson (1988) for the 
herpetofauna of Middle America. 
The checklist documents 395 native species of amphibians and 
reptiles described from 1756 through 1992 (Table 1). This 
taxonomic effort can be divided into four periods based on four 
different average rates of species description. The average rate 
was second highest between 1756 and 1766 during the time of 
Linnaeus (2.9 described species a year for 32 species). The 
slowest period spanned from 1767 to 1849, with only 42 new 
species described (0.5 a year). The highest rate of discovery 
(3.8 species a year) occurred between 1850 and 1899, when 188 
species were described. The rate from 1900 through 1992 has 
dropped to 1.4 a year (133 species). The latter two rates are 
almost linear. Since the latest rate is not approaching an 
asymptote, it isn't possible to estimate total Panamanian 
amphibian and reptile diversity. With only about twenty percent 
of the country's primary forests relatively intact, many species 
undoubtedly are already extinct or on the verge of extinction. 
Panama's complete pre-European herpetofaunal diversity will 
probably never be known, even after unexploited material in 
museum collections is analyzed. 
Approximately two-thirds of the known native amphibians and 
reptiles of Panama were described before 1900 (10.4% prior to 
1800, 55.9% in the 1800's). Edward Drinker Cope (80 species) and 
Wilhelm C. H. Peters (29 species) alone described slightly over 
one-fourth of the known fauna from 1860 to 1899. Linnaeus 
described 31 native species, Boulenger 26, Dunn 28, Taylor 20, 
and Dumeril, Bibron, and Dumeril 16. Thus, only nine taxonomists 
described 58 percent of Panama's known herpetofauna. 
