to the Sixth Edition
Since the first edition of this book was published in 1975, subsequent editions and printings have noted the growth in taxonomic knowledge of the Australian herpetofauna from the 664 species recognised in 1975 through 703 species (1979), 830 (1983), 865 (1986), 951 (1992), 990 (1994), 1004 (1996) to the 1050 species listed in this 2000 printing.
This unprecedented growth has resulted largely from the factors identified in the first edition preface (reprinted on the next page): the exploration of previously remote areas, increased awareness of the biological and ecological importance of our herpetofauna, and the application of new methods in discriminating biological species.
The format of earlier editions was radically revised in 1992 to include many more photographs, including a much greater use of colour. Moreover it placed the illustrations adjacent to the relevant text, and the keys are now accompanied by some hundreds of explanatory line drawings. I hope that these changes have made the book more reliable and more friendly to use, and that ultimately they will enhance its primary objective: the accurate identification of Australia's rich fauna of frogs and reptiles.
Probably the most persistent response from users of earlier editions has been the request to explain the use of different zoological names, in different books, for what is apparently the same animal, and for advice as to which of two or more names is “correct".
A corollary of the rapid growth in the naming of new species is that few of them have been subject to rigorous assessment by other herpetologists using a variety of discrimination techniques. Consequently a number of them may well be shown in the future to represent no more than variations within a single biological species, just as many of what we currently regard as well-defined species will be shown to represent two or more morphologically similar but reproductively isolated species.
Does this matter? Not at all; indeed, this is the very essence of taxonomic research in which new species are proposed, on the evidence available, so that others later may apply objective tests of their validity.
Elsewhere (p.25) I have stressed the importance of distinguishing between species and the names that we apply to them. Remember also that whereas most biologists believe that species are natural entities that can be objectively defined with adequate data and tools, genera and higher classifications are intrinsically subjective. Thus different classifications simply represent different interpretations, by different specialists, of the evolutionary or cladistic relationships of particular groups of organisms.
Despite occasional claims to the contrary, there is no "correct" classification, only classifications that are perceived by someone to best fit the available data. Hence, taxonomic opinions vary, and where my use of names or interpretation of relationships differs from that of other published views, I have attempted to at least indicate what those alternative opinions are.
The users of biological names (and of the biological classifications which they express) should always bear this last statement in mind, because they will then understand, and hopefully be more tolerant of, the frustratingly frequent scientific name changes and alternative classifications that continue to plague Australian herpetology.
As in the 1996 reprint, the only changes to the main text have been the correction of typographic and other errors, and the replacement of 44 maps. However, the Appendix has been updated to include changes and published additions available as at 31 May, 1999.
To further assist the reader in monitoring changes between editions, new taxonomies and name changes listed in the Appendix have been fully incorporated in the List of Currently Recognised Species of Australian Reptiles and Amphibians (p.7), which now represents an updated classification of Australian frogs and reptiles. As a consequence the names listed will not always coincide with those used in the body of the text. However, in both this list and the Index, all references to a particular !axon are cross-referenced, so that recent taxonomic changes will be as clear as possible to the book's users. For the general reader, the great majority of species remain unaffected.