Schilluk ridged frog (Ptychadena schillukorum)
|Also known as:||Schilluk grass frog, Sudan grassland frog|
|Synonyms:||Abrana cotti, Abrana floweri, Ptychadena cotti, Ptychadena floweri, Ptychadena frontalis, Rana cotti, Rana floweri, Rana frontalis, Rana mascareniensis schillukorum, Rana schillukorum|
|Size||Male snout-vent length: 4.3 - 4.8 cm (2)|
Female snout-vent length: 4.3 - 4.9 cm (2)
- The Schilluk ridged frog is named for the light-coloured ridges that run along its back.
- The Schilluk ridged frog sometimes eats other frogs, with one specimen being seen to eat a closely related species a third of its own size.
- Although it usually inhabits swampy areas, the Schilluk ridged frog can also survive in dry savanna and grassland.
- In parts of West Africa, the Schilluk ridged frog is commonly sold as food.
The Schilluk ridged frog is classified as Least Concern (LC) on the IUCN Red List (1).
The Schilluk ridged frog (Ptychadena schillukorum) is a compact, medium-sized frog which is found in a wide variety of habitats across Africa (2). It is usually light olive-grey with dark brown bars across its hind limbs and dark brown spots on its back. The common name of the Schilluk ridged frog refers to the presence of light-coloured vertical ridges running down its back (3).
The underparts of the Schilluk ridged frog are whitish, sometimes with mottling on the throat. There is usually a black patch on the eyelids and a dark ‘V’ shape between the eyes. This species has relatively short but thick hind legs (2).
The male and female Schilluk ridged frog are very similar in appearance, but the female is slightly larger on average, while the male has vocal sacs running from the corner of its mouth to the top of its front legs (2) (3).
The Schilluk ridged frog is widespread across Africa. Its range extends from Senegal east to Egypt, Ethiopia and Somalia, and south to Malawi, Mozambique, Namibia, Angola and South Africa (1) (2) (3).
However, although the Schilluk ridged frog has been recorded across a wide area, there are very few records from most of its range. Where it occurs it is apparently common, but its distribution is quite patchy (1).
The Schilluk ridged frog usually inhabits swampy areas where there is shallow water present, but it can also survive in arid savanna and grassland habitats (1) (3). It is often seen near rivers and lakes (1) (2), and may breed in flooded grassland, partially flooded rice fields and temporary pools (1).
The diet of the Schilluk ridged frog mostly consists of large, active, terrestrial invertebrates such as spiders, cockroaches, crickets and grasshoppers (2). It may also feed on other frogs (1), with one specimen being seen to eat a closely related species, Ptychadena mascareniensis, that was a third of its own size (3).
Many sightings of the Schilluk ridged frog occur during the daytime, which suggests that this is when it is most active (3). The Schilluk ridged frog usually breeds in flooded areas such as rice fields or flooded grassland, created by the first rainfalls (1) (2). The males have been seen calling to females while partially submerged in water, at the base of tufts of grass, as well as while floating at the water’s surface (2).
The Schilluk ridged frog lays small, brown-white eggs (2). Little other information is available on the breeding behaviour of this species.
The Schilluk ridged frog is not currently thought to be at risk of extinction, and its populations are generally stable. It has a widespread distribution and is an adaptable species that is able to live in a variety of different habitats (1).
However, although the Schilluk ridged frog is not believed to be facing any major global threats (1), it may be threatened locally in some parts of its range. For example, in Burkina Faso and Nigeria, this amphibian is one of a number of frog species that are consumed and traded as a source of protein. The scale of this frog trade may be unsustainable in some areas, with potential impacts on both the frog populations and the ecosystems they inhabit (4) (5).
There are no known specific conservation measures currently in place for the Schilluk ridged frog, but it occurs in a number of protected areas across its range (1).
It has been recommended that the frog trade in West Africa needs more detailed investigation to ensure that it does not have negative impacts on the region’s amphibians and ecosystems. In particular, more information is needed on the basic biology and life histories of the species involved. Public awareness should be raised locally on the importance of amphibians to the environment, and alternative sources of income should be explored (4).
Find out more about the Schilluk ridged frog and other amphibians:
More information on amphibian conservation:
IUCN/SSC Amphibian Specialist Group:
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- Invertebrates: animals with no backbone, such as insects, crustaceans, worms, molluscs, spiders, cnidarians (jellyfish, corals, sea anemones) and echinoderms.
IUCN Red List (February, 2011)
AmphibiaWeb - Ptychadena schillukorum (February, 2011)
- Baha El Din, S. (2006) A Guide to the Reptiles and Amphibians of Egypt. American University in Cairo Press, Cairo.
- Mohneke, M., Onadeko, A.B., Hirschfeld, M. and Rödel, M.-O. (2010) Dried or fried: amphibians in local and regional food markets in West Africa. TRAFFIC Bulletin, 22(3): 117-128.
African Amphibians Lifedesk - Ptychadena schillukorum (July, 2012)