A small Heterixalus (SVL of males 22-23 mm); back is whitish with small black spots. Other characters see next section.
Holotype: Adult male, ZFMK 57413, from a small artificial lake near the bifurcation of the road to Andasibe from the RN2, central eastern Madagascar. SVL 23 mm, head width 8 mm; eye diameter 3.1 mm, tympanum indistinct; distance eye-nostril 1.9 mm, distance nostril-tip of snout 1.7; hand length 6.5 mm, length of foot and tarsus 15 mm. Tibiotarsal articulation reaches between eye and nostril. Tibia is longer than foot. Tips of fingers and toes circularly enlarged. A nuptial pad is present on the inner side of the first finger. Vomerine teeth are absent. A gular gland is present, and posteriorly slightly notched, thus slightly of kidney shape. Webbing of the hand 1(-), 2i(-), 2e(1), 3i(2), 3e(1.5), 4(1); webbing of the foot 1(0), 2i(1), 2e(0), 3i(1), 3e(0), 4i/e(1.5), 5(0.5). Skin on the back smooth. In life dorsally silvery white with many (ca. 28) small black spots. Flanks and venter yellowish. These two colours border dorsilaterally, and are separated by a dorsilateral line of black spots. A black streak runs from nostril to eye.
Paratypes: Two adult males (ZFMK 57414, SVL 23 mm, and ZFMK 57415, SVL 22 mm) from the same locality as holotype. Morphological features and colouration very similar to the holotype. The number of black spots on the back is ca. 22 and 23, respectively.
Colour at night yellowish-brown, during the day bright white. The population at the type locality Andasibe, and specimens from Nosy Boraha, have small black spots on dorsum. However, specimens from Sambava are devoid of spots, while the syntopic H. madagascariensis at this locality often does have spots. In all specimens, the white dorsal colour does not extend onto the sides of the head which is yellowish. The feet are yellow and not orange as in H. madagascariensis. Similar species: H. madagascariensis is larger, has no dark spots on the back (as far as known) and differs by call. From H. rutenbergi, H. alboguttatus, H. betsileo, H. luteostriatus, H. andrakata, H. "variabilis" and H. boettgeri it can be easily distinguished by colouration. H. tricolor differs by call and its back is not distinctly spotted.
Taken with permission from Glaw and Vences (2007).