Description
Similar to other Breviceps, B. acutirostris is small, globose, and short faced frog, with a downturned mouth. Sexually dimorphic, the females may reach 40 mm in snout-vent length, whereas the males are usually less than 25 mm (Poynton 1963, Channing 2001). The snout is slightly more pointed and projecting than other taxa in the genus (reflected by the specific epithet; Poynton 1963). The distance between nostrils is slightly greater than the distance between nostril and eye. The eyes are small. The distance between eyes is close to but less than equal to the width of the upper eyelid, less than the horizontal diameter of eyes (Poynton 1963).The tympanum is usually not visible (Channing 2001), but this can be variable, including within individuals (e.g. in the holotype the tympanum is faintly distinguishable on right side but invisible on left side; Poynton 1963). The dorsal surface is covered by large, often black, porous, warty granules that may fuse in the vertebral region (Poynton 1963, Du Preez and Carruthers 2009). Both the dorsal and ventral surfaces are generally granular (Channing 2001), and the throat is more heavily granular in males (Du Preez and Carruthers 2009). Granules on the chin and throat are smaller than those more posterior where they are more flattened (Poynton 1963). Tubercles on the palms are poorly developed with single basal subarticular tubercles on each forelimb digit. The fingers are short, with the first very slightly shorter than the second, the fourth reaching the distal subarticular tubercle of the third, and nearly as long as the second (Poynton 1963). On the hindlimb, the inner metatarsal tubercle is well developed, there is no webbing between toes, and the inner and outer toes are longer than they are wide (Passmore and Carruthers 1995). The inner metatarsal tubercle is larger than outer. The outer toe extends well beyond the basal tubercle of the fourth, reaching further than the second. The inner toe is the smallest (Channing 2001).

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COLORATION:

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Distribution and Habitat

Country distribution from AmphibiaWeb's database: South Africa

View distribution map in BerkeleyMapper.

Breviceps acutirostris is endemic to the Cape Floristic Region within the southern Cape Fold Mountains in Western Cape, South Africa (Channing 2001). Details of the type locality are sparse, only mentioning the Swellendam Mountains, Western Cape Province, collected by G. Hutchinson on 5 February 1927 (Conradie et al. 2015). This species prefers thick forest—both canopy and undergrowth—with substantial leaf litter (Passmore and Carruthers 1995), but may also inhabit fynbos or grasslands, from sea level (where the mountains reach the coast) to 1600 m, but below the Great Escarpment (Channing 2001, Du Preez and Carruthers 2009, IUCN 2013, Nielsen et al. 2018). The species is often associated with Grey Sandy Soils and Table Mountain Sandstone (van Dijk 1982).

Life History, Abundance, Activity, and Special Behaviors
Breviceps acutirostris is fossorial, preferring well-drained loamy or sandy soils, to which they burrow in with their hind legs, rotating as they go (Du Preez and Carruthers 2009).

The male calls from ground level, elevated perches, or in shallow depressions under vegetation or leaf litter, emitting a short whistle (1.9 kHz with a duration of 200 ms), generally produced rapidly in succession (Channing 2001, Du Preez and Carruthers 2009). Calling occurs during and after rains, day or night, in winter and spring (Du Preez and Carruthers 2009). They will also vocalize even when a related species, B. fuscus, is within meters of a calling male (Channing 2001).

All members of the genus reproduce via direct development. Clutches contain ~24 large (7 mm) eggs (Du Preez and Carruthers 2009).

Larva
All members of the genus Breviceps reproduce via direct development (Du Preez and Carruthers 2009).

Trends and Threats
The distribution of B. acutirostris encompasses numerous protected areas, including Marloth and Ruitersbos Nature Reserves, Boosmansbos Wilderness Area, and Grootvadersbosch State Forest. It does not adapt well to alteration of its habitat (IUCN 2013), a pattern reflected in the citizen science observations listed on iNaturalist.

Comments

PHYLOGENETIC RELATIONSHIPS:

OTHER INTERESTING INFORMATION:

Based on paleoclimatic niche modeling, the geographic distribution of B. acutirostris between 6 Kya and 21 Kya could potentially have been greater, even encompassing the exposed Agulhas shelf area (Schreiner et al. 2013).

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

Conradie, W., Branch, W. R., and Watson, G. (2015). Type specimens in the Port Elizabeth Museum, South Africa, including the historically important Albany Museum collection. Part 1: Amphibians. Zootaxa, 3936(1), 42-70. [link]

Du Preez, L., and Carruthers. V. (2009). A Complete Guide to the Frogs of Southern Africa. Struik Nature

iNaturalist. Breviceps acutirostris https://www.inaturalist.org/taxa/25000-Breviceps-acutirostris. Accessed on 28 Nov 2023.

IUCN SSC Amphibian Specialist Group. (2013). Breviceps acutirostris. The IUCN Red List of Threatened Species 2013: e.T57711A3061868. https://dx.doi.org/10.2305/IUCN.UK.2013-2.RLTS.T57711A3061868.en. Accessed on 28 November 2023.

Nielsen, S. V., Daniels, S. R., Conradie, W., Heinicke, M. P., 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]

Passmore, N. and Carruthers, V. (1995). South African Frogs, a Complete Guide. Witwatersrand University Press, Johannesburg, South Africa.

Poynton, J. C. (1963). Descriptions of southern African amphibians. Annals of the Natal Museum, 15(24), 319-332. [link]

Schreiner, C., Rodder, D., and Measey, G. J. (2013). Using modern models to test Poynton's predictions. African Journal of Herpetology, 62(1), 49-62. [link]

Van Dijk, D. E. (1982). Anuran distribution, rainfall and soils in Southern Africa. South African Journal of Science, 78(10), 401. [link]

Species Account Citation: AmphibiaWeb 2024 Breviceps acutirostris: Strawberry Rain Frog (English) <https://amphibiaweb.org/species/2371> University of California, Berkeley, CA, USA. Accessed Dec 30, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 30 Dec 2024.

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