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Amphibia    Anura    Bufonidae  
Dixie Valley Toad
Anaxyrus williamsi (Gordon, Simandle, and Tracy, 2017)
AH-naks-EE-rus — WIL-yamz-eye
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Amphibian Species of the World
Catalog of American Amphibians and Reptiles
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USGS Nonindigenous Aquatic Species Database

SSAR 9th Edition Comments:
 This isolated population was diagnosed with respect to other taxa and populations in the A. boreas group based on data from morphology and mitochondrial DNA. See comments under A. boreas. (Mendelson, Joseph R., III, Darrel R. Frost, Emily Moriarty Lemmon, and Maureen A. Donnelly. 2025. Anura – Frogs. Pages 1-9 in Kirsten E. Nicholson (Editor), Scientific and Standard English Names of Amphibians and Reptiles of North America North of Mexico, with Comments Regarding Confidence in Our Understanding, 9th Edition. Society for the Study of Amphibians and Reptiles, Lawrence, Kansas. 87 pp.)

(,   Museum Voucher) (,   Observation) (,   Literature Record), (,   Citizen Science), (  Fossil)
Open icons indicate questionable records, including those with coordinate uncertainty greater than 10,000 m (approximately 6 miles). Click a marker to view metadata.
Occurrences:; 14 Total; 8 Museum; 6 Other

The locality database contains 8,094,832 records, and geographic and taxonomic errors exist. Logged-in, registered users may report a potential issue directly from the marker popup.
Shaded range maps are based on curated specimens and provided gratis by CNAH. (Version: 2025.06.20.00.10.30)
Download map data (GeoJSON):
Polygon Range File Museum Literature Fossil Personal Observation Citizen Science

Province/State Distribution:
United States: Nevada

Taxonomic Etymology:
The name combines classical Greek roots with a patronym honoring an individual:
Anaxyrus — From Greek: ἀνάξ (anax) = “lord” or “king”; ταῦρος (tauros) = “bull” (though not directly present in the name, it's likely implied in reference to the former genus Bufo, meaning "toad"). While the exact reasoning is not fully clarified in the genus description, Anaxyrus is often interpreted to mean “lordly toad” or “king of toads,” reflecting its large size or distinctive presence among North American toads.
williamsi — A patronym, honoring Robert Williams, for his significant role in supporting amphibian conservation in Nevada and California. The Latinized suffix -i indicates it is named after a male individual.

First instance(s) of published English names:
No historic English names have been assigned to this taxon yet.


Selected References:
1959 Baldauf, Richard J. Morphological criteria and their use in showing bufonid phylogeny. Journal of Morphology 104(3):527-560.
1962 Tihen, Joseph A. A review of new world fossil bufonids. The American Midland Naturalist 68(1):1-50
2004 Pauly, Gregory B., David M. Hillis, and David C. Cannatella. The history of a Nearctic colonization: Molecular phylogenetics and biogeography of the Nearctic toads (Bufo). Evolution 58:2517-2535
2008 Pauly, Gregory B. Phylogenetic systematics, historical biogeography, and the evolution of vocalizations in Nearctic toads (Bufo). Dissertation. University of Texas, Austin. 165pp.
2017 Gordon, Michelle R., Eric T. Simandle, and C. Richard Tracy. A diamond in the rough desert shrublands of the Great Basin in the Western United States: A new cryptic toad species (Amphibia: Bufonidae: Bufo (Anaxyrus)) discovered in Northern Nevada. Zootaxa 4290(1):123–139
2023 Dodd, C. Kenneth. Frogs of the United States and Canada. Second Edition. John Hopkins University Press, Baltimore, Maryland. 1032pp.

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