Illinois Natural History Survey - University of Illinois

Anaxyrus fowleri (Hinckley, 1882) -- Fowler's Toad

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A_fowlClinton.JPG Anaxyrus_fowleri_ShelbyCo_2012dorsal.JPG A_fowlVenterClinton.JPG
Clinton Co., IL  photo by C.A. Phillips  Shelby Co., IL photo by A.R. Kuhns Clinton Co., IL  photo by C.A. Phillips

A_fowleri.jpgKey Characters: Three or more small warts in each dark dorsal spot; venter immaculate or with small dark blotch; cranial crests low and less massive than American toad.

Similar Species: American Toad has one or two warts in each dark dorsal spot and a darkly colored venter, Eastern Spadefoot has no cranial crest and has vertical pupils. See Key to Illinois Frogs & Toads for help with identification.

Subspecies: None recognized.

Description: Medium-sized (up to 8 cm SVL), gray to greenish gray toad with large dark back spots roughly in pairs flanking light mid-back stripe. Chest and belly white or gray; dark pigment, if any, limited to small spot on chest. Transverse cranial crest in broad contact with parotoid gland. Hybrids with Aamericanus have intermediate features.

Habitat: A wide variety of habitats where flooded fields, ditches, and other bodies of water are available for reproduction.

Natural History: Adults are active on the surface day and night. Diet consists of insects, earthworms, and other invertebrates. Breeding takes place from late April to late June. The male breeding call, a short "waaaa," is heard from shallows of ponds and lakes and flooded ditches. Eggs are laid in long strings. Eggs and tadpoles are similar to those of American toad. Embryos hatch in a week and transform from June through July.

Status: Occasionally hybridizes with American toad in lower Mississippi River valley. Common in southern half of state and along Illinois and Mississippi rivers (see distribution map, left).

Etymology: Anaxyruys- (Greek) a king or chief; fowleri - (New Latin) in honor of Samuel Fowler (1799-1844), doctor, legislator, and mineralogist. 

Original Description: Hinckley, M. H. 1882. On some differences in the mouth structure of tadpoles of the anourous batrachians found in Milton, Mass. Proceedings of the Boston Society of Natural History 21: 307–314.

Type Specimen: Not designated.

Type Locality: Milton, Mass

Original Name: Bufo fowleri

Nomenclatural History: Placed in synonymy of Bufo woodhousii by Smith, 1934:456 (Smith, H. M. 1934. The amphibians of Kansas. American Midland Naturalist 15: 377–516.), but resurrected to full species by Sanders, 1987:1-28 (Evolutionary Hybridization and Speciation in North American Indigenous Bufonids. Dallas, Texas: Privately printed).

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