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Schismaderma carens
Red Toad
family: Bufonidae

© 2012 Simon J. Tonge (1 of 22)

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Conservation Status (definitions)
IUCN (Red List) Status Least Concern (LC)
See IUCN account.
CITES No CITES Listing
Other International Status Least concern (IUCN)
National Status None
Regional Status None

   

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Description
Schismaderma carens, commonly known as the Red Toad, is a moderate to large-sized toad. Males can reach 88 mm, and females can reach 92 mm in snout-vent length. This toad has a less warty back than many toads of the same size. A distinct dorsolateral glandular ridge runs from above the tympanum to the hind leg. The outer part of the dorsolateral ridge is darker on the lower edge. The tympanum itself is large and round, with a diameter approximately equivalent to that of the eye. Parotoid glands are not visible. A tarsal fold is present. Breeding males have vocal sacs, as well as nuptial pads on their first three fingers for amplexus (Channing and Howell 2006).

The back is characteristically marked by a pair of small dark brown spots on the lower back and another pair of markings on the shoulders. Dorsal coloring is reddish, hence the common name of Red Toad. The ground color is pale brown and even pinkish at times. The flanks are either pale or very dark. The underside is speckled with gray (Channing and Howell 2006).

The tadpole has an unusual horseshoe-shaped flap of skin on the head (Channing 2001).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Angola, Botswana, Congo, the Democratic Republic of the, Kenya, Malawi, Mozambique, Namibia, South Africa, Swaziland, Tanzania, United Republic of, Zambia, Zimbabwe

View distribution map using BerkeleyMapper.
Schismaderma carens is widely distributed throughout Central and Southeast Africa. The northern-most parts of its range cover northwestern Tanzania and Olorgesailie in southern Kenya. The species occurs down through southeastern Democratic Republic of Congo, eastern Angola, and Western Zambia, and also reaches southeastern Botswana, southern Mozambique, Swaziland, Malawi, Namibia, Zimbabwe, and the Eastern Cape Province of South Africa. Although it has not been recorded in Lesotho, it also possibly occurs there (Poynton et al. 2004).

The Red Toad tolerates a broad range of habitats, but occurs primarily in grassland and wooded savannah. It also occurs on livestock ranches, around human settlements, and on agricultural land. This species is terrestrial and breeds in freshwater. Its breeding grounds are usually bodies of deep, still water, including dirty water (Poynton et al. 2004).

Life History, Abundance, Activity, and Special Behaviors
Although the Red Toad is common, it is much easier to find when it is breeding (Poynton et al. 2004). Calling occurs predominantly in the midsummer, and the males call while floating in the shallow water to advertise themselves to females (Channing and Howell 2006). The call sounds like a loud, long whoop, with a duration of 0.9-1.2 seconds and dominant harmonics between 0.1 and 0.8 kHz. Calls are made during the day.

After heavy rainfall, the toad breeds during the day in deep muddy water. Males reach the breeding grounds, among the younger vegetation in the deep water, before the females. Dense spacing is the norm, with males separated by as little as 300 mm from each other. The males proceed to call and chase each other, while actively trying to mate with other frogs. Females then enter the area in response to the calls. The eggs are laid in a double string during amplexus while the pair moves slowly in the water, producing rows of egg strings. Eggs may be attached to vegetation, and females leave shortly after laying their eggs. The clutch size is 2500, with each egg 1.6-2.5 mm in diameter. Since myriad toads lay their eggs at similar times, the waters may be filled with upwards of tens of thousands of eggs at a time. The period of development from egg to toadlet ranges from 37 to 52 days.

The Red Toad has gregarious tadpoles, sometimes found in mixed swarms with tadpoles of the African bullfrog Pyxicephalus adspersus. These tadpoles are unique morphologically due to a horseshoe-shaped flap of skin on the head (Channing 2001; Channing and Howell 2006).

The adult molts at 4 day intervals (Channing and Howell 2006).

Trends and Threats
The Red Toad is a fairly abundant and widespread species that is not currently threatened. The tadpoles may be preyed upon by dragonfly nymphs, helmeted terrapins (Pelomedusa subrufa), the hammerkop (Scopus umbretta), and hinged terrapins (genus Pelusios). The savanna vine snake Thelotornis capensis eats juvenile Red Toads, while the white-lipped snake Crotaphopeltis hotamboeia and the eagle owl Bubo lateus consume adult toads (Channing and Howell 2006).

Relation to Humans
The Red Toad often lives in very close proximity to humans.

Comments
The specific name carens is Latin for "lacking" and refers to the lack of parotoid glands (Channing and Howell 2006). Other common names include the Red-backed toad, African split-skin toad, kazoli in Lwena and Manganja, conga in Sena, naliwonde in Yao, rooiskurwepadda in Afrikaans, and zonde in Chewa.

Biochemical evidence suggests that S. carens has been separated from other toads evolutionarily for approximately 55 million years (Channing 2001).

References
 

Channing, A. (2001). Amphibians of Central and Southern Africa. Cornell University Press, Ithaca, NY.  

Channing, A., and Howell, K. M. (2006). Amphibians of East Africa. Cornell University Press, Ithaca.  

Poynton, J.C., Howell, K., Minter, L., and Tandy, M. (2004). Schismaderma carens. In: IUCN 2007. 2007 IUCN Red List of Threatened Species. www.iucnredlist.org. Downloaded on 07 August 2008.



Written by Amy Ru Chen (amychen AT fas.harvard.edu), Harvard
First submitted 2008-05-13
Edited by Kellie Whittaker (2008-08-27)



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Citation: AmphibiaWeb: Information on amphibian biology and conservation. [web application]. 2014. Berkeley, California: AmphibiaWeb. Available: http://amphibiaweb.org/. (Accessed: Aug 1, 2014).

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