Stanley’s Warty Frog
Species Description: Loader SP, Gower DJ, Ngalason W, Menegon M 2010 Three new species of Callulina (Amphibia: Anura: Brevicipitidae) highlight local endemism and conservation plight of Africa's Eastern Arc forests. Zool J Linn Soc 160: 496-514.
© 2010 Michele Menegon (1 of 1)
DESCRIPTION:Callulina stanleyi is one of the medium to large species of Callulina frog species. More specifically, the maximum snout to the urostyle length is around 42.5 mm and the snout-vent to tibia ratio ranges from around 0.33 - 0.39. It has a larger, more robust head to go along with its robust body. On the head, the tympanum is present; however, it can be difficult to detect due to the bumpy skin. The skin is granular and warty. In terms of hand proportions, when the tips of the phalanges are spread apart, the ratio of widths of the first subarticular arch to the distal phalanx ranges from 0.8 - 1.0. The digits have truncated tips. In the holotype, the order of finger length from shortest to longest is: first finger, second and fourth fingers are equal, and then the third finger. A noteworthy feature on their hands is the prominent subarticular tubercles of the hands. When looking at the feet of the holotype, the toe tips were a tad expanded to the side and were smooth on the underside. The order of toe length from shortest to longest is: first and second toe are equal, then the third and fifth toe are equal, and the fourth toe is the longest. Similar to the hands, the subarticular tubercles of the feet are also prominent (Loader et al. 2010). Callulina stanleyi does not have large glands in their limbs (Menegon et al. 2011).
Members of the Callulina genus are easily characterized by the appearance of granular warty skin and the truncation of toes and fingertips. Most of the morphological distinctions that can be made for C. stanleyi is in the hand morphology. Unlike C. kreffti, C. stanleyi has less expansion in the third finger. However, C. stanleyi still has expanded fingertips and toe tips, which can be distinguished from species such as C. dawida that do not have this feature. The presence of a tympanum can distinguish it from other Callulina species that lack a tympanum such as C. laphami and C. shengena. Callulina kisiwamsitu is the most morphologically similar, but can be distinguished from C. stanleyi through the use of genetics, their calls, and geographic location in which they are found (Loader et al. 2010). Lastly, C. stanleyi does not have large glands in their limbs, as seen in C. meteora (Menegon et al. 2011).
Callulina stanleyi coloration in life is characterized by a brown body with an irregular, mottled appearance with white warts running along the sides of the body. The underside of the body has a light cream color. The transition from the darker brown to the lighter cream appears blended as the darker brown marbling can be seen on the edges of this cream color. The subarticular tubercles in both the hands and feet are bluish grey. The eyes are a range of orange to red in color (Loader et al. 2010).
Variation can be seen in the degree of darkness and degree of mottling of the brown coloration. Furthermore, the degree to which the tympanum is obscured also varies from individual to individual (Loader et al. 2010).
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Tanzania, United Republic of
Life History, Abundance, Activity, and Special Behaviors
General characteristics of Callulina species are that they are terrestrial, arboreal, breed during the dry season, which is from June to October. Around July, males begin to advertise themselves using a distinct mating call that is only known in the South Pare Mountains (Malzona 2008).
Male C. stanleyi call at night from low branches of bushes or trees. This call has 7 to 9 sharp trills per call, each of which lasts 1 to 2 seconds. The frequency of these calls can reach a maximum of 1720 Hz. The pulse duration for each group lasted around 25 ms, while the intergroup pulse duration lasted around 116 ms (Loader et al. 2010).
In general, female Callulina lay eggs and their offspring undergo direct development. This genus exhibits parental care, as females brood their eggs from when they are deposited in September to when they begin hatching in November. These eggs are cared for in a nested structure in the leaf litter. Although abundant information does not exist on average clutch size, Malonza (2008) observed a female Callulina with 30 to 40 eggs in her clutch that were approximately 2 mm in diameter around the time of deposition in September. The eggs are composed of yolk surrounded by jelly capsules. Offspring develop relatively fast and will reach reproductive age at around 8 months of age (Malonza 2008).
ABUNDANCE: It was estimated that the abundance of C. stanleyi was not low at around 2010 (Loader et al. 2010). An abundance of Callulina sp. is determined by temperature and altitude, such that abundance increases during warmer months and with an increase in altitude. These warmer months include January to March and August to October. Abundance is less during the colder months of June and July and during the rainy season in April, November, and December. Juvenile abundance noticeably increases from January to March (Malonza 2008). ACTIVITY: In general, Callulina species is nocturnal. However, there have been cases where a Callulina sp. has been roaming during the day. Since they are mostly arboreal and terrestrial, they may be found on the ground of the forest floor or perched on a tree or leaf that is off of the ground. The species is usually solitary. However, there have been two instances where two adult individuals were found a meter apart and two juveniles a meter apart (Malonza 2008). SPECIAL BEHAVIORS: There are two documented different ways that Callulina sp. reacts to it being disturbed or handled. 1) Frog inflates and arches its body. It tucks its head into its body. It can produce sticky gum. 2) If it was moving beforehand it is disturbed or handled, it freezes or stays immobile (Malonza 2008).
Possible reasons for amphibian decline
General habitat alteration and loss
PHYLOGENETIC RELATIONSHIPS:Maximum likelihood, Maximum Parsimony, and Bayesian Inference of 12S, 16S and cytochrome b showed that the most closely related species to C. stanleyi is C. kisiwamsitu. The next most closely related species is C. kreffti followed by C. dawida. The clade composed of these species is sister to the clade composed of C. laphami, and C. shengena (Loader et al. 2010).
Callulina stanleyi is named after William T. Stanley, who made various contributions to the biological diversity of the Eastern Arc Mountains (Loader et al. 2010).
OTHER INTERESTING INFORMATION: C. stanleyi are very highly endemic to the northern part of the Eastern Arc Mountains (Loader et al. 2010). They are considered an ‘afrotemperate’ species, which means they are part of a group of species that live in the southern Cape, eastern highlands of South Africa, and intertropical highlands (Poynton 2013).
IUCN SSC Amphibian Specialist Group, 2020. “Callulina stanleyi (amended version of 2012 assessment).” The IUCN Red List of Threatened Species 2020: e.T193429A176116120. https://dx.doi.org/10.2305/IUCN.UK.2020-3.RLTS.T193429A176116120.en. Downloaded on 21 January 2021.
Loader, S. P., Gower, D. J., Ngalason, W., and Menegon, M. (2010). ''Three new species of Callulina (Amphibia: Anura: Brevicipitidae) highlight local endemism and conservation plight of Africa's Eastern Arc forests.'' Zoological Journal of the Linnean Society, 160, 496-514.
Malonza, K. P. W. (2008). "Amphibian Biodiversity in Taita Hills, Kenya." University of Mainz, Mainz, Germany
Menegon, M., Gower, D. J., Loader, S. P. (2011). “A remarkable new species of Callulina (Amphibia: Anura: Brevicipitidae) with massive, boldly coloured limb glands.” Zootaxa 3095,15-26.
Originally submitted by: Elise Israel, Alice Kim, Raquel Ponce (2021-08-12)
Description by: Elise Israel, Alice Kim, Raquel Ponce (updated 2021-08-12)
Distribution by: Elise Israel, Alice Kim, Raquel Ponce (updated 2021-08-12)
Life history by: Elise Israel, Alice Kim, Raquel Ponce (updated 2021-08-12)
Comments by: Elise Israel, Alice Kim, Raquel Ponce (updated 2021-08-12)
Edited by: Ann T. Chang (2021-08-12)
Species Account Citation: AmphibiaWeb 2021 Callulina stanleyi: Stanley’s Warty Frog <https://amphibiaweb.org/species/7583> University of California, Berkeley, CA, USA. Accessed Aug 15, 2022.
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Citation: AmphibiaWeb. 2022. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 15 Aug 2022.
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