AMPHIBIAWEB
Phrynobatrachus stewartae
family: Phrynobatrachidae
Conservation Status (definitions)
IUCN (Red List) Status Least Concern (LC)
CITES
Other International Status None
National Status None
Regional Status None

Country distribution from AmphibiaWeb's database: Malawi, Tanzania, United Republic of

 

View distribution map using BerkeleyMapper.

   

From the Encyclopedia of Life account:

Summary

Phrynobatrachus stewartae is a small species (SVL < 23 mm) of puddle frog from Malawi and Tanzania. Members of this genus are identified by the presence of a midtarsal tubercle, elongate inner metatarsal tubercle, and outer metatarsal tubercle. This species exhibits moderate webbing, extending beyond the proximal subarticular tubercle on toe IV, and lacks digital discs. Males have grey throats and exhibit a baggy gular region with a posterior gular fold, as well as conspicuous, yellow femoral glands in life.


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

Etymology

This species is named in honor of Dr. Margaret Stewart, who first collected this species and wrote the landmark text, Amphibians of Malawi. Stewart was part the biology faculty of the University at Albany from 1956 to 1997, although remained active even after retirement. In 1979, Stewart became the first woman to lead a professional herpetological organization when she was elected president of the Society for the Study of Amphibians and Reptiles (SSAR). In 2005, she was awarded the American Society of Ichthyologists and Herpetologists (ASIH) Robert K. Johnson Award for excellence in service to the society and the Henry S. Fitch Award, for long-term excellence in the study of amphibian, chelonian, and/or reptilian biology.


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

Distribution

It is so far known only from two localities: Rumpi in northern Malawi and Mulenge Forest in south-central Tanzania. It most likely occurs in between these two localities and may occur more widely (Channing et al., 2004).


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

Morphology

It is a small species (SVL < 23 mm) of puddle frog that is like other dwarf Phrynobatrachus in proportions but has a number of characteristics that allow its identification. Members of this genus are identified by the presence of a midtarsal tubercle, elongate inner metatarsal tubercle, and metatarsal tubercle. Manual webbing is absent. Pedal webbing is moderate with the broad web extending 1/3 to 2/3 of way between subarticular tubercles of toe IV and extending beyond the proximal subarticular tubercle on toe IV on the inner side. Margin of web reaches the distal tubercle of toe III and middle tubercle of toe IV, continuing as a fringe. Toes not dilated into discs. Dorsum is brown with a dark triangle between the eyes. The upper and lower jaws are barred. Large, flattened femoral glands are present in males and are conspicuously yellow in life. The male throat is grey with a saggy gular sac that exhibits a clear posterior fold (Stewart, 1967; Poynton and Broadley, 1985; Channing and Howell, 2006).


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

Size

Phrynobatrachus stewartae is a small (snout–vent length < 23 mm) puddle frog species. Males grow up to 21 mm long and females up to 23 mm (Channing and Howell, 2006). According to Poynton and Broadley (1985), male SVLs do not exceed 20 mm.


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

Diagnostic Description

Phrynobatrachus stewartae exhibits moderate webbing, extending beyond the proximal subarticular tubercle on toe IV, and lacks digital discs. Males have grey throats, a baggy gular sac with a prominent posterior flap, and conspicuous, yellow femoral glands in life.


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

Comparisons

This species differs from many other East African dwarf puddle frogs because the extent of its webbing. Most small species, including P. inexpectatus, P. kakamikro, P. keniensis, P. mababiensis, P. minutus, P. parvulus, P. pallidus, P. scheffleri, P. rungwensis, P. ukingensis, and P. ungujae have absent or rudimentary webbing. P. uzungwensis exhibits moderate to extensive pedal webbing, but not the grey throat and gular sac described in male P. stewartae. P. anotis has a yellow throat in life. P. stewartae and P. breviceps (SVL < 17.5 mm) appear to be most similar in extent of webbing and size. Male P. stewartae and P. breviceps also share the dark throat and baggy gular sac, but a median gular fold is absent in the former.


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

Habitat and Ecology

It appears to be restricted to marshy areas in dry forest and grassland, especially where there is vegetation in the water. Its altitudinal range is unclear, though it probably occurs above 1,200m asl. (Channing et al., 2004).


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

Activity and Special Behaviors

Males call from under vegetation in marshy areas (Channing and Howell, 2006). The call is a typical dwarf puddle frog advertisement with a long buzz, terminating with one or more ticks, but it has not yet been recorded. It is similar to Phrynobatrachus mababiensis, but it is longer, faster, and louder.


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

Metamorphosis

A gravid female contained darkly pigmented eggs that were 0.6 mm in diameter (Channing and Howell, 2006).


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

Phylogenetics

No sequence data is currently available for this species.


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

IUCN Red List Category and Justification of Conservation Status

The IUCN Red List (2009) categorizes this species as Data Deficient in view of continuing uncertainties as to its extent of occurrence, status and ecological requirements (Channing et al., 2004).


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

Conservation Actions and Management

It occurs in Mulenge Forest Reserve, and it is also likely to occur in Nyika National Park (Channing et al., 2004).


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/