Phrynomantis annectens Werner, 1910
Original Published Description:
Marbled Rubber Frog (English), Red-spotted Frog (English), Red-spotted Namibia Frog (English), Red Marbled Frog (English), Cape Snake-necked Frog (English)
The Marbled rubber frog (Phrynomantis annectens) is one of the few native amphibians to the Namib Desert, who survives by finding deeper water pools in inselbergs and other rocky formations. This anuran ranges southward to the Nama and Succulent Karoo areas; northward to the Kaokoveld Desert and Angola mopane woodlands; and eastward to the Kalahari xeric savanna and Namibian savanna woodlands. (WWF & Hogan. 2012)
P. annectens is endemic to the larger Namib region, from Angola southward through western Namibia, reaching South Africa in the extreme northern parts of Northern Cape Province (Text from Minter et al., 2004, © SI/MAB Biodiversity Program).
Habitat and Ecology
The average annual rainfall in this region is <60 mm (Text from Minter et al., 2004, © SI/MAB Biodiversity Program).
Predators of the adults have not been recorded, but dragonfly nymphs are known to prey on the tadpoles (Text from Minter et al., 2004, © SI/MAB Biodiversity Program).
Channing (1976, 2001) Breeding takes place immediately after the first rains of spring or summer. Males call from the edges of small pools formed by the runoff from sheets of rock, or in the deeper rock pools remaining in drainages after the rains. Females lay 80–100 eggs in groups of 2–8 and attach them to submerged rock surfaces or vegetation (Minter et al., 2004, © SI/MAB Biodiversity Program).
Development is quickly and free swimming tadpoles hatch within 18–36 hours. Older tadpoles are large and transparent with flattened heads and conspicuous fins, flecked with silver and gold. They are gregarious, forming schools that hang in the water column and filter out unicellular algae and diatoms (Channing 2001). The tadpole stage lasts at least eight weeks before metamorphosis is completed. During the dry season the adults aestivate in deep rock cracks (Text from Minter et al., 2004, © SI/MAB Biodiversity Program).
IUCN Red List Category and Justification of Conservation Status
The distribution of P. annectens is mainly extralimital and it occurs in many protected areas in Namibia and Angola. In South Africa the habitat occupied by P. annectens is not heavily exploited, hence the species is not classified as threatened. However, quarrying and mining lead to the pollution of surface water by fuels and lubricants used to run and maintain heavy machinery, and this will affect local populations (Text from Minter et al., 2004, © SI/MAB Biodiversity Program).
- Phrynomantis nasuta Methuen and Hewitt, 1913 (synonym)
- Hoplophryne marmorata Ahl, 1934 (synonym)
- Ctenophryne marmorata Ahl, 1935 (synonym)
- Phrynomerus annectens — Parker, 1936 (synonym)
- Phrynomantis annectens — Dubois, 1988 (synonym)
- Phrynomantis annectans — Bauer and Branch, 2001 (synonym)