Body shape is compact and toad-like, and the habit is stout. Vomerine teeth are present in two oblique groups between the moderately large choanae, and the tongue is notched. The head is short and broader than long; snout is rounded. Nostril is much closer to the lip than the anterior eyelid. Tympanum is distinct, round and measures 1/2 to 3/4 as large as the eye diameter. The interorbital distance is less than the width of the upper eyelid. The subarticular tubercles are single and distinct. Toes are one-third webbed; approximately three phalanges are free of webbing on the fourth toe. The inner metatarsal tubercle is prominent and shovel-shaped, longer than the first toe. A small, round outer metatarsal tubercle is present, and tarsal tubercle is absent. The tibia may be the same size or slightly longer than the femur. The dorsal skin is generally smooth with some small, isolated warts. A discontinuous or continuous glandular ridge is present below the tympanum, trailing from the back edge of the mouth. Males have a nuptial pad on manual digit I and sometimes digit II. The gular flap is thickened U-shaped in males. In alcohol, the color may be light grey, light brown or orange-brown with darker markings. A light vertebral line is variably present, and an interorbital bar may be present. Limbs are barred. Males have a dark throat, abd females have a mottled throat (Zimkus and Larson, 2011).
Tomopterna kachowskii differed from other species in the genus by 3.5%–6.3% (T. delalandii) to a maximum of 7.7%–7.9% (T. elegans), while intraspecific variation was 0.0–0.7% (Zimkus and Larson, 2011).
Tomopterna kachowskii and T. elegans are distinguished from other species of sand frogs by their visible tympana, presence of an outer metatarsal tubercle and moderate pedal webbing. Tomopterna elegans is distinguished from T. kachowskii by slightly more extensive webbing and variable presence of a discontinuous row of small glands beneath the tympanum (Zimkus and Larson, 2011).
The following is a translation of the original description of Chiromantis (Tomopterna) kachowskii by A.M. Nikolskii (1900) from the original Latin by B.M. Zimkus.
No 2077. Ferad in Abyssinia 1898 (2).
Vomerine teeth in two oblique groups between the choanae; the distance between the groups is the size of one group, equal with the inner margin of the choanae; the width of the head is wider than the length; snout rounded, snout length is greatest longitudinal diameter of the eye, loreal region of the head concave; distance from the nostrils to the snout tip less than the distance to the anterior eye; tympanum diameter 1/2 the longitudinal diameter of the eye; interior palmar digits scarcely
webbed, exterior as long as 1/3 palm; toes long, almost completely webbed, digital discs small, or indistinct; large subarticular tubercles, inner metatarsal tubercle large, scaphoid; small external metatarsal tubercle; with the hind leg placed forward, the tibio-tarsal articulation reaches the anterior margin of the eyes; olive-gray color above, with spots of brown on the back, on the male a long, white line that extends from the snout to anus. underside white, with the front margin of the
mandible black in the male; total length 35 mm. Collected near Ferad in Abyssinia.
Snout-vent lengths of specimens examined by Zimkus and Larson (2011) are as follows: males, 33.7–42.6 mm (mean 38.9 mm, n=10); females, 35.9–54.1 mm (mean 48.0 mm, n=7).
This species is known from Ethiopia and Somalia. The exact distributions of this species within Ethiopia, Somalia and Eritrea are unclear, and it is possible that its range extends west into Sudan.