Systematics of the Bufo woodhousii complex (Anura: Bufonidae): Advertisement call variation

To determine whether Bufo fowleri, Bufo woodhousii woodhousii, and Bufo woodhousii australis are diagnosable taxa, we examined variation in advertisement calls and body size across the range of the Bufo woodhousii complex. Calls were recorded and toads measured in six regions consisting of California, Arizona, Utah, Texas, Nebraska and Iowa, and New Jersey. Pulse rate and call duration, but not frequency, were significantly related to temperature. Dominant frequency was the only call variable of the three analyzed that correlated with snout-vent length. When adjusted for temperature and size effects, calls of B. fowleri had a shorter duration and higher dominant frequency than the other two members of the B. woodhousii complex. Discriminant analysis using call variables and body size provided clear separation of B. fowleri from B. w. woodhousii and B. w. australis. Univariate and multivariate analyses revealed that toads from southern California were most similar to toads from south-central Arizona currently recognized as B. w. australis. We conclude that B. fowleri should be recognized as a species. Continued recognition of B. w. australis and B. w. woodhousii as western forms of the B. woodhousii complex is reasonable.