The snout-vent length can reach 250 mm for females, with males slightly smaller, reaching 180 mm (Norman 1994). The head is short and broad, with distinct cephalic crests (Lutz 1934). The skull has broad frontoparietals whose lateral edges form distinct supraorbital crests, which then extend forward onto the nasal bones to form canthal and preorbital crests (Brandão et al. 2007). Both supraocular and retroocular crests are present, the supraocular crest forming an obtuse angle with the retroocular crest (Lutz 1934).
The snout is rounded in dorsal view and truncate in profile. A distinct tympanum is visible, slightly smaller than the eye itself. Behind the eyes are large bean-shaped parotoid glands (Lutz 1934). The pupil is large and slit-shaped (Norman 1994).
The body is globular, short and stout (Norman 1994). Limbs are short, and the hind legs are weak. A tibial gland, which secretes a milky bufotoxin, runs down each hind leg (Lutz 1934). Fingers/toes are fairly slender and the inside toes and fingers are bent outwards. There are no expanded discs. There is no webbing on the fingers, but there is very minimal webbing between the toes. The relative length of the digits is as follows: II>III>I>IV for fingers, and V>IV>III>I>II for toes. There are no tubercles on the fingers or toes. Males have nuptial pads on their thumbs (Norman 1994). The skin is rough, covered with blunt, spiny warts that are usually conical (Norman 1994). These abundant warts are light near the bottom and spotted with black on the top (Lutz 1934).
Dorsally, B. schneideri is brownish to yellowish (Norman 1994). The belly and throat are whitish and closely speckled with dark spots.
Along the middle of the back are chocolate brown transverse blotches or spots. The sides and the dorsum have whitish spots and reticulations, with fewer on the dorsum. Males may also have large black spots dorsally (Lutz 1934).
Tadpoles are 24.31 mm +/- 1.26 mm at stage 36 to 38.
The body is oval and depressed when viewed dorsally, and globular/depressed when viewed laterally. The snout is rounded in dorsal view and sloped in lateral view. Eyes are dorsal and directed laterally. Nares are large, oval-shaped and directed dorsolaterally, with a very small projection on the marginal rim. Nares length is greater than 1/2 the diameter of the eye. The spiracle is medial and laterally directed, with the opening located at two-thirds of the body length. The vent tube is short and medial, and fused with the ventral fin. The dorsal fin distinctly rises during the last third of the tail, and the ventral fin is low. The tadpole's oral disc is anteroventral and emarginated laterally. Papillae are small and triangular, with a row of submarginal papillae sometimes present. The tooth row formula is 2(2)/3(1), where A-1 and A-2 are equal in length and P-2 is slightly longer than P-3. The jaw sheaths are narrow, with triangular serration. The upper jaw is arc-shaped while the lower jaw is u-shaped (Rossa-Feres and Nomura 2006).
The tadpole body is gray (Cei 1980) while the tail is dark with translucent fins (Rossa-Feres and Nomura 2006).
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Argentina, Bolivia, Brazil, Paraguay, Uruguay
This species is known from North and Central Argentina (Missiones, Corrientes, Chaco, Entre Ríos, Formosa, Jujuy, Salta, Santiago del Estero, Cordoba, Santa Fe, and Tucumán), central Bolivia (Beni, Cochabamba, Chuquisaca, Santa Cruz, Tarija), and the Atlantic coast of Brazil (from Ceará to Río Grande do Sul), Paraguay, and Uruguay (Artigas, Salto, Paysandu, Río Negro, and Soriano). It has been found at elevations up to 2,000 m asl. It occurs in a wide variety of habitats, from open, urban areas to the Chaco, Cerrado, and Atlantic Forest regions (Stuart et al. 2008).
Life History, Abundance, Activity, and Special Behaviors
Bufo schneideri is nocturnal and terrestrial. It occasionally burrows in deep soil. It climbs on rocks and roots. Its dry, rough skin, burrowing habits, and activity at night all allow B. schneideri to live in drier regions of South America (Norman 1994).
It breeds from October to April, although the rainy season lasts only from October until March. Bufo schneideri is thus one of the few species in the genus Bufo which is able to breed during the dry season.
The advertisement call is a low resonant trill resembling the sounds of a stake being rapidly hammered. Males also give a slightly higher pitched release call if other males mount them, with the release call being a low "squeegeeing" noise, like a window being washed. Bufo schneideri vocalizes throughout the year, while most other species only vocalize and reproduce during the warm, rainy period (Norman 1994).
The female deposits her eggs in a pool of temporary or permanent open water without much vegetation (Stuart et al. 2008). Eggs are laid in long strands in the bottom of the water. The clutch is large (well over 2,000 eggs) and the eggs may occur in double rows (Caldwell et al. 2007). The eggs hatch as tadpoles. Bufo schneideri tadpoles eat planktonic algae, unlike other bottom-dwelling tadpoles that consume periphytic algae. At night, the tadpoles have been seen swimming upside down just below the water's surface (Rossa-Feres et al. 2004).
Snakes and other predators eat Bufo schneideri. It can puff up with air to avoid being swallowed by snakes, and its brownish color works as camouflage. The bufotoxin it secretes can cause nausea, vomiting, and even paralysis and death in potential predators (Norman 1994).
The species is fairly abundant (Stuart et al. 2008).
Trends and Threats
This species is generally common and increasing, although its range appears to be contracting in northern Cordoba and Jujuy, Argentina. There are no known threats to this species, except for elimination by apiculturists where it occurs near areas of beekeeping. It is sometimes collected for the international pet trade but at levels that currently appear sustainable. It occurs in several South American national parks where the species is protected (Stuart et al. 2008).
Relation to Humans
It is collected occasionally for the international pet trade. Since it has been observed to eat bees at hives, apiculturists consider it a pest and work to eliminate it in beekeeping areas (Stuart et al. 2008).
It may possibly represent a species complex (Stuart et al. 2008).
Brandão, R. A., Maciel, N. M., and Sebben, A. (2007). ''A new species of Chaunus from central Brazil (Anura; Bufonidae).'' Journal of Herpetology, 41, 309-316.
Caldwell, J. P., and Shepard, D. B. (2007). ''Calling site fidelity and call structure of a neotropical toad, Rhinella ocellata (Anura: Bufonidae) .'' Journal of Herpetology, 41, 611-621.
Cei, J. M. (1980). ''Amphibians of Argentina.'' Monitore Zoologica Italiano, New Series Monografia, Firenze, 2, 1-609.
Lutz, A. (1934). ''Notas sobre espécies brasileiras do gênero Bufo.'' Memórias do Instituto Oswaldo Cruz, 28, 111-159.
Norman, D. R. (1994). Anfibios y Reptiles del Chaco Paraguayo, Tomo 1. (Amphibians and Reptiles of the Paraguayan Chaco, Volume 1.) . Private printing, San José, Costa Rica.
Rossa-Feres, D. C., Jim, J., and Fonseca, M. G. (2004). ''Diets of tadpoles from a temporary pond in southeastern Brazil (Amphibia, Anura).'' Revista Brasileira de Zoologia, 21(4), 745-754.
Rossa-Feres, D. C., and Nomura, F. (2006). ''Characterization and taxonomic key for tadpoles (Amphibia: Anura) from the northwestern region of São Paulo State, Brazil.'' Biota Neotropica, 6, 1-26.
Stuart, S., Hoffmann, M., Chanson, J., Cox, N., Berridge, R., Ramani, P., and Young, B. (eds) (2008). Threatened Amphibians of the World. Lynx Edicions, IUCN, and Conservation International, Barcelona, Spain; Gland, Switzerland; and Arlington, Virginia, USA.
Written by Rachel Wagley (rwagley AT fas.harvard.edu), Harvard College
First submitted 2008-05-14
Edited by Kellie Whittaker (2009-03-31)
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