Does body size predict dates of species description among North American and Australian reptiles and amphibians?

Which factors determine whether a species is obvious to collectors? For some taxa, species of small body size tend to be described later than large-bodied species, perhaps because large animals are more obvious or easily captured. Thus it has been proposed that current estimates of species numbers within taxa may be biased, as they may not include small species. However, the trend for recently described species to be small-bodied has only been observed in a few higher taxa, and may not be general. Herein, we examine the relationships between body size and date of description for the entire herpetofaunas of North America and Australia (snakes, lizards, turtles, frogs and salamanders). We found that body size is generally a poor predictor of description date in herpetofaunal taxa. Even for most taxa that did exhibit a negative relationship between these variables, recently described species could not be distinguished from a random draw from overall species pools. We interpret our results in the light of the history of exploration of these continents and the biology of reptiles and amphibians.