Anaxyrus—Nearctic Toads // Incilius—Middle American Toads
The common name of the family sometimes is given as Common Toads, which fits well since various members occur from low desert to high mountains and many have fairly large populations.
Until recently, all members of the family in our region were assigned to the genus Bufo. Nomenclature has been changing rapidly; when this page first went up, the Center for North American Herpetology, our standard for herpetological taxonomy, recognized two genera (Anaxyrus and Ollotis) within our region, with the genus Bufo having been limited to the eastern hemisphere (Frost et al. 2006). Now, our species that had been placed in the genus Ollotis have been assigned to the genus Incilius (Frost et al. 2009).
Bever (2005) conducted extensive research on the utility of the bufonid ilium, an element frequently used for identification of fossil taxa. The beginning of his discussion and conclusions section is quoted below (Bever 2005):
My data indicate that characters traditionally used to identify fossil ilia of North American Bufo exhibit too much intraspecific variation and are too widely distributed among species to be useful in species-level identifications. No discrete characters or non-overlapping continuous characters were found that unambiguously identify any of the 27 extant species and nine species groups examined in this study.
Although Bever shows that some taxa may be discriminated from some other taxa (e.g., on size), there appears to be no known character or suite of characters that will separate any of the 27 extant species studied from all other North American species. This being the case, specific identifications given here are suspect.
Literature. Bever 2005; Frost et al. 2006; Frost et al. 2009.
Last Update: 30 Dec 2009