Reptiles and Amphibians 



Overview 



Amphibians and reptiles 

 are important elements of 

 our national biological heritage and deserve 

 special attention. They are crucial to the natural 

 functioning of many ecological processes and 

 key components of important ecosystems. In 

 some areas certain species are economically 

 consequential; others are aesthetically pleasing 

 to many people, and as a group they represent 

 significant segments of the evolutionary history 

 of North America. Knowledge gained from past 

 study of amphibian development and metamor- 

 phosis has contributed immensely to our under- 

 standing of basic biological processes and has 

 directly benefited humans. 



The native herpetofauna of the continental 

 United States includes about 230 species of 

 amphibians (about 62% of which are salaman- 

 ders and 38% frogs) and some 277 species of 

 repfiles (about 19% turtles, 35% lizards, 45% 

 snakes, and less than 1% crocodilians). If the 

 list were expanded to include native species 

 from Puerto Rico and the U.S. Virgin Islands in 

 the Caribbean. Hawaii, the Trust Territory of the 

 Pacific Islands, and the U.S. Territories in the 

 Pacific, the amphibian list would increase by 

 about 20 native species (all frogs) and another 5 

 non-native frog species. If the reptile inventory 

 were expanded similarly, the list would increase 



by 2 turtles. 83 lizards, 1 8 snakes, and 1 croco- 

 dilian. Another 2 species of turtles, 17 lizards, 2 

 snakes, and 1 crocodilian have been introduced. 

 An updated summary of this information is 

 scheduled for publication later this year 

 (McDiamiid, unpublished data). 



Many U.S. reptile and amphibian checklists 

 and field guides have been written over the past 

 50 years. The data for such summaries come 

 from researchers working with various aspects 

 of the biology of amphibians and reptiles and 

 are found in many scientific publications. These 

 summary field guides give the impression that 

 the herpetofauna of the United States is well 

 known and well studied. When we realize how 

 little is known of the herpetofauna of compara- 

 ble areas in South America, such an assumption 

 is valid. A cursory review of U.S. data, howev- 

 er, provides a somewhat different view. Since 

 1978 the total herpetofaunal diversity of the 

 United States has increased by almost 12%, 

 from 454 to 507 species. Much of that increase, 

 though, has resulted from a new knowledge of 

 complex groups of species (e.g., eastern pletho- 

 dontid salamanders) through the application of 

 molecular techniques to gain a better under- 

 standing of the patterns of species formation 

 and of the phylogenetic (evolutionary) history 

 of certain groups. New species are still being 



Science Editor 



Roy W. McDiarmid 



National Biological 



Service 

 National Museum of 



Natiiral History 

 Washington, DC 20560 



