An Endangered Wildlife Trust ecologist recently joined two other South African researchers to confirm the discovery of a new sand frog species in the genus Tomopterna in Mozambique’s Banhine National Park.

A small collection of frogs from inland of Beira, Mozambique, in December 1991 included two specimens of Tomopterna that differed morphologically and genetically from all previously known species. In subsequent years a series of Tomopterna specimens was collected from Banhine National Park. Genetic results indicated that the Banhine specimens were genetically closely related to those collected near Beira, and that these sequences differed substantially from all previously sequenced Tomopterna species.

In findings published in ZOOTAXA, EWT ecologist Darren Pietersen, North West University’s Alan Channing and the SA Medical Research Council’s Abeda Dawood describe this new frog species, which they name Tomopterna banhinensis after the type locality, as a species that can be distinguished from all other described species of sand frogs by several characters.

These include that the males grow to a maximum size of 43 mm, that all individuals have two pairs of divided tubercles under the first finger, more than three phalanges free of webbing on the fourth toe, a continuous glandular ridge below the tympanum, a distinct tympanic membrane, the nostrils being situated closer to the snout tip than to the eye, the absence of an outer metatarsal tubercle, the presence of small dorsal warts, the absence of (or only weak) vomerine teeth, and barring on the limbs.

This description adds a further amphibian to the list of Mozambican frogs, which has increased significantly in recent years.

According to the published research, there are presently 18 recognised species within the genus Tomopterna.

The research shows that the species of sand frogs are very similar in overall morphology, no doubt the reason why so many cryptic species were unrecognised, or synonymised with the Cryptic Sand Frog (T. cryptotis) – which was believed to be a single widespread taxon.

Sand frogs are widely distributed in sub-Saharan Africa, excluding the rainforests of central Africa. They are usually found on sandy soils, although the Eastern Beaded Sand Frog (T. pulchra) and Natal Sand Frog (Tomopterna natalensis) are prone to inhabit more rocky habitats.

While this species is presently only known from Banhine National Park and the area around Beira in Mozambique, it is likely to be more widespread than present records suggest, occurring widely across the Mozambique plain, possibly including extreme south-eastern Zimbabwe (specifically Gonarezhou National Park), to which the sandveld and drainage systems of Banhine National Park are linked.

The research paper states that the discovery of many cryptic sand frog species using DNA sequencing suggests that there are more frog species waiting to be described. Sand frog species often occur sympatrically, but the high diversity of Tomopterna, up to five species, on the coastal plain of Mozambique is remarkable.

Research published by:

ALAN CHANNING1, DARREN W. PIETERSEN2,3 & ABEDA DAWOOD4
1Unit for Environmental Sciences and Management, North-West University, Potchefstroom 2520, South Africa.
2Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa.
3Endangered Wildlife Trust, Plot 27 & 28 Austin Road, Glen Austin AH, Midrand 1685, South Africa
4Division of Research Capacity Development, South African Medical Research Council, Private Bag X385, Pretoria 0001, South Africa.