AMPHIBIAWEB
Ptychadena schillukorum
Schilluk ridged frog
family: Ptychadenidae
Conservation Status (definitions)
IUCN (Red List) Status Least Concern (LC)
CITES No CITES Listing
Other International Status None
National Status None
Regional Status None

 

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Description
A medium-sized rather compact ranid with comparatively short and massive hind legs. SVL of males 43–48 mm, females reach 43–49 mm. Males with paired lateral vocal sacs whose slits run parallel to the jaw border and end near the bases of the forearms, i.e. above the latter. The head width equals its length. The distance snout tip–nostril is less than the distance between the nostrils and the distance nostril–eye. The tympanum reaches 0.7 of the eye diameter. The dorsal and lateral ridges are divided into elongate wart-like structures. The skin of the flanks is granulated to warty. The foot is shorter than the shank, and the latter does not reach half of the SVL. The fourth toe with 1–2 free phalanges. The inner metatarsal tubercle is small, an outer one is absent (Stewart 1967, Poynton 1970).
Coloration: No light lines or bands on the back or on the dorsal part of the shanks. The rather discontinuous dorsal ridges are black. The light colored remains of the dorsolateral ridges have fine black borders. A black patch marks the eyelids. A dark "V" is present between the eyes. The anterior border of the vocal sac and the canthal area are somewhat darker, and the upper lip is light colored, showing no markings. This white color stretches to the upper arm where another isolated white bulge is found. The arms are feebly mottled. Black bars are present on the legs: three bars usually appear on the thighs, and 3–4 on the shanks. These bars are often paler centrally. The outer part of the thigh is speckled, adorned with irregular light lines or densely spotted with black. The lower jaw is either feebly spotted or mottled. The throat is mottled or shows no coloration at all. The underside of the foot is dark, and the webs are slightly pigmented dark. The rest of the venter is uniform whitish (Boulenger 1917, Stewart 1967, Poynton 1970). According to Stewart (1967) some frogs possibly have light vertebral bands and light lines on their hind limbs.
Voice: Schiøtz (1964c) describes a call lasting 0.4 sec with a dominant frequency of 3–4 kHz. It comprises 6–7 notes consisting of 5–6 pulses, each. Similar data are published by Van der Elzen & Kreulen (1979). Amiet (1974c) reports on a call lasting 0.36 sec.

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Benin, Burkina Faso, Cameroon, Egypt, Ethiopia, Ghana, Kenya, Malawi, Mauritania, Mozambique, Namibia, Senegal, Somalia, South Africa, Sudan, Tanzania, United Republic of

 

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Range: This species has not yet been recorded at Comoé National Park. According to Frost (1985), the range stretches from Senegal to Egypt, and southwards to Tanzania, Malawi and Mozambique. Duellman (1993) corrected the range to Senegal to Sudan. Records have been published for the following countries: Senegal, Ghana, Burkina Faso, Cameroon, Egypt, Sudan, Somalia, Kenya, Tanzania, Malawi, Mozambique, South Africa, Namibia (Boulenger 1917, Loveridge 1925, 1936, Schiøtz 1964a, c, 1967, Perret 1966, 1979b, Stewart 1967, Lamotte 1969, Poynton 1964a, c, 1966, 1970, Laurent 1965, Amiet 1973a, 1974, Stevens 1974, Van der Elzen & Kreulen 1979, Lanza 1981, Hughes 1988, Channing 1989, 1993, Pickersgill 1994). Largen (1998) cites P. schillukorum for Ethiopia.
Habitats: According to Stewart (1967), this species is encountered on the banks of rivers and lakes. In Ghana, it is found in the Sudan savanna (Schiøtz 1964c, Hughes 1988). Lamotte & Xavier (1981) quote arid habitats.

Life History, Abundance, Activity, and Special Behaviors
Spawn: Small brown-white eggs (Stewart 1967).
Tadpoles: Unknown.
Biology: The males invade flooded grasslands after the first rainfalls (Loveridge 1933). A partially submerged male was found calling in a habitat of that kind, i.e. at the base of a grass tuft near the bank of a puddle (Van der Elzen & Kreulen 1979). According to Amiet (1974c), males call while they are floating at the water surface. Channing (1989) found these frogs in very dense vegetation at the edge of shallow ponds. Amiet (1974c) and Schiøtz (1964c) quote alluvial land bearing a thick vegetation and partially flooded rice fields where the frogs sit at the edges of small puddles. Inger & Marx (1961) found that their prey mainly comprise large active terrestrial animals, i.e. orthopterans, spiders and cockroaches. The diet was not subject to seasonal changes.

Comments
This account was taken from Rödel, M.-O. (2000), Herpetofauna of West Africa vol. I. Amphibians of the West African Savanna, with kind permission from Edition Chimaira publishers, Frankfurt am Main.
For references in the text, see here

References

Rödel, M. O. (2000). Herpetofauna of West Africa, Vol. I. Amphibians of the West African Savanna. Edition Chimaira, Frankfurt, Germany.



Written by M.O. Roedel (roedel AT biozentrum.uri-wuerzburg.de), Post-Doc at the University of Wurzburg, Department of Animal Ecology and Tropical Biology, Wurzburg, Germany
First submitted 2001-05-07
Edited by Arie van der Meijden (2002-02-08)

Species Account Citation: AmphibiaWeb 2002 Ptychadena schillukorum: Schilluk ridged frog <http://amphibiaweb.org/species/4953> University of California, Berkeley, CA, USA. Accessed Oct 17, 2017.



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Citation: AmphibiaWeb. 2017. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 17 Oct 2017.

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