Family Pyxicephalidae

Tomopterna cryptotis (Boulenger, 1907)

Tremolo Sand Frog, Cryptic Sand Frog, Striped Pyxie, Trillersandpadda (A)

By A. Channing

Currently accepted name: Tomopterna cryptotis
Red listing status: Least Concern (IUCN 2016)

Photo by Wilkinson J H, 2012. URL: FrogMAP: 514

Distribution

Historical records indicate a wide distribution in the savannas of subsaharan Africa from Senegal in the west to Somalia in the east, and southward through East Africa to South Africa. However, on the basis of data available to this author, T. cryptotis appears to be distributed from Angola through Zambia to Malawi, and southward through Namibia, Botswana, Zimbabwe and Mozambique to the atlas region. In South Africa and Swaziland, T. cryptotis is known from the inland plateau and the dry interior regions.

There do not seem to be any morphological features that permit one to distinguish between T. cryptotis and the cryptic, tetraploid species T. tandyi. Their calls differ only slightly in pitch (Channing and Bogart 1996), and only a few people who collected atlas data were able to identify these species in the field. Also, relatively few tape recordings of calls of these species were submitted by volunteers for analysis. Nevertheless, M. Burger and H.H. Braack collected sufficient reliable records of T. tandyi, mainly in the southern parts of its range, to warrant the production of a separate distribution map for that species.

In the case of T. cryptotis, fewer reliable records, based on calls, are available. Had the existing data been vetted strictly (i.e., all uncertain records been deleted), the resulting map would have been uninformative. Therefore, in the interest of presenting the reader with a map that illustrates the range of this species at least reasonably well, most of T. cryptotis records (including historical records) were retained, but should be interpreted with caution. The southern limit of the range of T. cryptotis as depicted on the map may be regarded as reasonably accurate.

Habitat

This species inhabits various vegetation types in the Savanna and Grassland biomes. Breeding takes place in shallow, standing water at the edges of dams, pans, and even small bodies of water such as roadside puddles.

Life history

Individuals burrow into sandy soils or dry river beds during the dry season and, in the breeding season, may retreat into termite mounds during the day.

Breeding begins after the first spring rains and choruses may be heard throughout the rainy season after showers. Males call from exposed positions near the water’s edge, but are well concealed by their cryptic colouration.

About 2000–3000 eggs are laid singly in shallow water. Tadpoles reach 39 mm in length and larval development takes about five weeks.

Predators of the adults include the Hamerkop Scopus umbretta and Barn Owl Tyto alba (Broadley 1974), while fishing spiders and terrapins prey upon the tadpoles.

Conservation

T. cryptotis appears to be widespread and locally abundant, and does not require conservation action. However, its conservation status may have to be revised once new distribution maps, based on more accurate records, have been produced.

Current distribution map

Undated records;  pre-1996;  1996 to 2002;  2003 to present