Phrynobatrachus natalensis (Smith, 1849)
Original Published Description:
Smith's Frog (English), Puddle Frog (English), Snoring Puddle Frog (English), Natal Frog (English), Natal Puddle Frog (English), Common Toad-frog (English), Toad Frog (English), Natal River Frog (English)
This species is likely a complex of multiple cryptic species. Members of this genus are identified by the presence of a midtarsal tubercle, elongate inner metatarsal tubercle, and outer metatarsal tubercle. P. natalensis is a medium to large sized puddle frog (SVL < 40 mm) with variable dorsal coloration and patterns, but most often brown with a light vertebral stripe. Finger tips lack disks or distinct swelling. The tympanum is visible and larger than ½ the diameter of the eye. Webbing is not consistent, possibly because of taxonomic confusion.
This species ranges very widely in the savannah zone of Africa, from Senegal and Gambia, east to Ethiopia and Eritrea, south to Angola, Namibia, Botswana and South Africa and occurs on the island of Zanzibar, Tanzania. It presumably occurs in Burkina Faso, Chad and Lesotho (Rödel et al., 2004).
P. natalensis is widely distributed in the savannas of sub-Saharan Africa, from Senegal in the west to Somalia in the east and southward through East Africa. To the south, it ranges as far as northeastern Namibia, northern Botswana, and Eastern Cape Province of South Africa (Text from Minter et al., 2004, © SI/MAB Biodiversity Program).
Phrynobatrachus natalensis most likely represents a complex of cryptic species due to its widespread distribution, and morphological diversity of eggs, larvae, and adults (Rödel, 2000; Channing, 2001; Largen, 2001; Channing and Howell, 2006; Pickersgill, 2007; Zimkus et al., 2010).
Rödel (2000) reported the variation in clutch size, tadpole morphology, size of the adult frog and period of activity, suggests that this taxon may comprise more than one species (Text from Minter et al., 2004, © SI/MAB Biodiversity Program).
Most individuals are dark brown with variable dorsal patterns, including light vertebral stripes and bands. Finger tips lack disks or distinct swelling. The tympanum is visible and larger than ½ the diameter of the eye. Webbing is not consistent, possibly because of taxonomic confusion (Harper et al., 2010).
Stewart (1974) suggests that the polymorphic colour pattern may be a means of protection against predators, and specific patterns have been correlated with particular habitats (Text from Minter et al., 2004, © SI/MAB Biodiversity Program).
Habitat and Ecology
It is typically associated with herbaceous vegetation along the margins of shallow marshes, lakes, rivers, streams and pools, both permanent and temporary. It is found in semi-desert scrub, arid and humid savannah, agricultural land, and even at clearings deep within forest. It occurs up to 2200m asl in Ethiopia (Rödel et al., 2004).
P. natalensis inhabits a variety of vegetation types in the Savanna and Grassland biomes where summer rainfall is >500 mm, although some populations along the western edge of the species’ range are found in drier areas (Text from Minter et al., 2004, © SI/MAB Biodiversity Program).
It is a widespread and often abundant species (Rödel et al., 2004).
Populations of this species are stable (Rödel et al., 2004).
Food items recorded north of the atlas region include a variety of insects, especially termites during the rainy season, as well as earthworms, snails and frogs (Inger and Marx 1961). Predators of the species include Blacknecked Spitting Cobra Naja nigricollis (Channing 2001) and Herald Snake Crotaphopeltis hotamboeia (Text from Minter et al., 2004, © SI/MAB Biodiversity Program).
Breeding takes place in shallow to fairly deep water in temporary pans and pools, vleis, dams and even small, slow flowing streams. Wager (1986) recorded the species breeding in brackish pools near the high-water mark at the coast. Breeding sites usually have vegetation or other types of cover along their banks. P. natalensis is tolerant of human disturbance and is often found near human habitation (Text from Minter et al., 2004, © SI/MAB Biodiversity Program).
Males usually call from concealed sites and may be heard throughout the day and night in wet weather. Aggressive encounters between males are commonplace (Wager 1965).Breeding begins in spring after the first rains and continues to late summer. Mating pairs swim while depositing the small eggs in a single-layered plate that floats at the surface (Text from Minter et al., 2004, © SI/MAB Biodiversity Program).
It breeds in temporary ponds and puddles, usually in still water associated with pans, streams or vleis (Rödel et al., 2004; Harper et al., 2010). Small dark brown eggs are laid in clutches of approximately 200 (Harper et al., 2010).
Males can be heard calling during the day as well as at night. Channing and Howell (2006) describe the call as “a slow quiet snore.”
Rödel (2000) found that this species hatches within 3–4 days and took 4–5 weeks to reach metamorphosis, but other authors report considerable variation in the rate of development (Text from Minter et al., 2004, © SI/MAB Biodiversity Program).
Metamorphosis is typically completed within 40 days (Harper et al., 2010).
Evolution and Systematics
In analyses by Zimkus et al. (2010), samples assigned to P. natalensis formed a clade but exhibited extraordinary genetic diversity. Pairwise sequence divergences of mtDNA among conspeciﬁc populations of P. natalensis varied from 0.2% to 12.2%. Five main clades were identiﬁed that had pairwise divergences greater than 4.7% (P. natalensis A–E). This complex was sister to a group containing P. acridoides, P. pakenhami, P. bullans, and P. francisci.
IUCN Red List Category and Justification of Conservation Status
The IUCN Red List (2010) categorizes this species as Least Concern in view of its very wide distribution, its tolerance of a broad range of habitats, its presumed large population, and because it is unlikely to be declining fast enough to qualify for listing in a more threatened category (Rödel et al., 2004).
It is well established in many national parks and provincial nature reserves and does not need additional conservation action (Text from Minter et al., 2004, © SI/MAB Biodiversity Program).
It is an adaptable species that is facing only local threats (Rödel et al., 2004).
Conservation Actions and Management
It occurs in many protected areas (Rödel et al., 2004).
In Burkino Faso, P. natalensis is one of many frog species that are traded or consumed as a source of animal protein. Frogs are an integral part of the economy in areas with large frog populations because villagers are employed to catch and prepare frogs, and because they are an "important international trading item." Aside from their value as an essential food source, frogs and, more commonly, toads may also be used for cultural reasons and as traditional medicine in areas where Western medicine is not available (Mohneke, 2010).
- Stenorhynchus natalensis Smith, 1849 (synonym)
- Phrynobatrachus natalensis Günther, 1862 (synonym)
- Dicroglossus angustirostris Cope, 1862 (synonym)
- Leptoparius natalensis — Peters, 1863 (synonym)
- Dicroglossus natalensis — Cope, 1865 (synonym)
- Arthroleptis natalensis — Peters, 1875 (synonym)
- Arthroleptis natalensis var. irrorata Peters, 1875 (synonym)
- Arthroleptis bottegi Boulenger, 1895 (synonym)
- Phrynobatrachus ranoides Boulenger, 1895 "1894" (synonym)
- Arthroletpis moorii Boulenger, 1898 (synonym)
- Phrynobatrachus natalensis forma gracilis Andersson, 1904 (synonym)
- Phrynobatrachus maculatus FitzSimons, 1932 (synonym)
- Phrynobatrachus natalensis — Deckert, 1938 (synonym)
- Phrynobatrachus natalensis — Deckert, 1938 (synonym)
- Phrynobatrachus (Phrynobatrachus) natalensis — Laurent, 1941 (synonym)
- Phrynobatrachus (Phrynobatrachus) ranoides — Laurent, 1941 (synonym)
- Phrynobatrachus (Pararthroleptis) bottegi — Laurent, 1941 (synonym)
- Phrynobatrachus moori — Laurent, 1941 (synonym)
- Arthroleptis-Phrynobatrachus natalensis — Scortecci, 1943 (synonym)
- Arthroleptis-Phrynobatrachus zavattarii Scortecci, 1943 (synonym)
- Arthroleptis-Phrynobatrachus sciangallarum Scortecci, 1943 (synonym)
- Phrynobatrachus duckeri Loveridge, 1953 (synonym)
- Arthroleptis sciangallarum — Gorham, 1974 (synonym)
- Phrynobatrachus sciangallarum — Frank and Ramus, 1995 (synonym)
- Phrynobatrachus zavattarii — Frank and Ramus, 1995 (synonym)
- Phrynobatrachus bottegi — Frank and Ramus, 1995 (synonym)