Description
Breviceps sopranus is a frog first described by Minter in 2003 based on only 14 male specimens with a snout-vent length range of 22.0 to 26.2 mm. The snout is abbreviated and the tympanum is hidden. Its pupils appear horizontal and elliptic. The skin on its dorsum is finely granular. This effect is caused by the minute tubercles that coat the area; the top of each tubercle contains a small dermal-gland opening. Conversely, B. sopranus’s ventrum is smooth. Breviceps sopranus has short limbs. Its fourth finger reaches the distal subartricular tubercle of the third finger. The subarticular tubercles of its third finger are fused. Its inner and outer metatarsal tubercles are separated by a slight groove, but are otherwise undivided. Its outer toe is a stub that reaches the bottom tubercle of its fourth toe (Minter 2003).

DIAGNOSIS: (How this species is different from similar species)

Breviceps sopranus can be differentiated from other species by skin texture, size, patterning, and vocalizations. The small frame, finely granular dorsal skin, and smooth ventral skin of B. sopranus differs from B. verrucosus’s large body and densely granular dorsum and ventrum. Breviceps verrucosus also has glandular ridges on its back and a long outer toe that does not align to the morphology of B. sopranus. When compared to B. adspersus, B. sopranus is much smaller. Breviceps sopranus has fewer prominent patches and a longer fourth finger. Breviceps sopranus also has a number of distinctive markings that differentiates it from other species, particularly the B. mossambicus, which does not typically display these markings. However, some specimens of B. mossambicus exhibits skin patches that are similar to those on B. sopranus. Breviceps bagginsi can also have these patterns. The most efficient way to distinguish B. sopranus from related Breviceps species is through advertisement calls, which have subtle duration and pitch differences that can be detected on a sonogram. Breviceps adspersus, B. mossambicus, and B. bagginsi have shorter, pulsed calls compared to the extended, uninterrupted call of B. sopranus (Minter 2003).

COLORATION: (Please indicate if it is in life and or in preservative or if it’s unclear from the text)

In life, B. sopranus has an olive brown hue. It tends to have faint, scattered dark speckles throughout its body and a bar between its eyes. The pectoral and belly region is starkly white with a few spots interspersed at its sides. However, individual patterning varies (see below). Preserved specimens of B. sopranus are light brown with similarly colored patches (Minter 2003).

VARIATION:

This frog is known to have a diverse range of coloration patterns. Breviceps sopranus often has a dark stripe that runs horizontally down its arm or thin stripe along its spine. Breviceps sopranus is characterized by its patches. Pale, typically light pink patches interrupted with darker areas are present on its stomach (Channing 2001). The species may also have two to four converging patches on its sides as well as a patch over its urostyle or pelvic area (Minter 2003).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: South Africa, Swaziland

View distribution map in BerkeleyMapper.

Breviceps sopranus is typically found in the well-wooded, sandy areas of eastern South Africa (Channing 2001), such as the Mpumalanga Province, Mananga Mountains, and Muti Muti Nature Reserve. It can be found in coastal forests and tall thornvelds with herbaceous understories (Minter 2003). This frog’s elevation range is from 0 to 350 meters above sea level (IUCN 2013).

Life History, Abundance, Activity, and Special Behaviors
Breviceps sopranus is most notable for its breeding call. The advertisement call is a long, unpulsed whistle that repeats at a rate of 21.4 calls per minute. On average, each repeated call lasts 1.5 seconds and has a frequency of 3332 Hz (Minter 2003, Pretorius 2019).

Breviceps sopranus begins calling at moderate relative humidities, ranging from 60% to 75% (Pretorius 2019) from perches 50 - 300 mm above the ground or on fallen branches and herbaceous plants under trees (Minter 2003). While they typically begin their calls when it is raining and cease choruses after showers dissipate, they are also recorded to call during nights without rainfall (Pretorius 2019).

Breviceps sopranus and B. mossambicus call from the same habitats (Channing 2001). Despite their active calls, male B. sopranus individuals often exhibit low intensity breeding patterns (Pretorius 2019).

Larva
Breviceps sopranus undergoes direct development in the egg, like all other Breviceps species (Minter 1998).

Trends and Threats
Breviceps sopranus is a "Least Concern" species because of their large extent of occurrence and the various range of habitats they are found in. However, sugar farming, afforestation, and subsistence farming are still threats to their survival (Measey 2011, IUCN 2013).

Possible reasons for amphibian decline

General habitat alteration and loss
Intensified agriculture or grazing

Comments

PHYLOGENETIC RELATIONSHIPS:

In the IsiZulu language, B. sopranos is referred to as Isinana sekhwela or somtshingo (Phaka et al. 2019).

References

Channing, A. (2001). Rain Frogs, Rubber Frogs—Family Microhylidae. In Amphibians of Central and Southern Africa (pp. 209–236). Cornell University Press. [link]

Measy, G. J. (2011). Ensuring a future for South Africa’s frogs: a strategy for conservation research. SANBI Biodiversity Series 19. South African National Biodiversity Institute, Pretoria. [link]

Minter, L. R. (1998). Aspects of the reproductive biology of Breviceps. Unpublished PhD thesis. University of the Witwatersrand, Johannesburg. [link]

Minter, L. R. (2003). Two new cryptic species of Breviceps (Anura: Microhylidae) from southern Africa. African Journal of Herpetology 52, 9–21. [link]

Nielsen, S. V., Daniels, S. R., Conradie, W., Heinicke, M. P., and Noonan, B. P. (2018). Multilocus phylogenetics in a widespread African anuran lineage (Brevicipitidae: Breviceps) reveals patterns of diversity reflecting geoclimatic change. Journal of Biogeography 45(9), 2067–2079. [link]

IUCN SSC Amphibian Specialist Group. 2013. Breviceps sopranus. The IUCN Red List of Threatened Species 2013: e.T57720A18362405. https://dx.doi.org/10.2305/IUCN.UK.2013-2.RLTS.T57720A18362405.en. Accessed on 25 October 2023.

Phaka, F.M., Netherlands, E.C., Kruger, D.J.D., and Du Preez, L.H. (2019). Folk taxonomy and indigenous names for frogs in Zululand, South Africa. J Ethnobiology Ethnomedicine 15, 17. [link]

Pretorius, W. W. (2019). Ecology and calling behaviour of the anurans of Northern Zululand, South Africa (dissertation). Natural and Agricultural Sciences. [link]

Species Account Citation: AmphibiaWeb 2024 Breviceps sopranus: Whistling rain frog <https://amphibiaweb.org/species/6245> University of California, Berkeley, CA, USA. Accessed Dec 28, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 28 Dec 2024.

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