Comparisons.—Dixon (1957) recognized six species of Tomodactylus (nitidus, dilatus, albolabris, angustidigitorum, fuscus and grandis) in his revision of the genus. Another species (rufescens) was subsequently described by Duellman and Dixon (1959). Tomodactylus saxatilis differs from all the species named immediately above by the combination of characters given in the diagnosis. Tomodactylus saxatilis differs from nitidus, angustidigitorum and grandis in having the tips of the two outer fingers widened and truncate; saxatilis differs from dilatus, albolabris, fuscus and rufescens in having a smooth venter (not pustulate), a contrasting pale and dark marbled pattern on the back, and a lack of "flash" colors on the femora.

Tomodactylus saxatilis, having lumbar glands, also resembles three species referred to the genus Syrrhophus. Tomodactylus macrotympanum was described by Taylor (1940:496, 497) as having a large, moderately distinct lumbar gland; the species was referred to the genus Syrrhophus by Dixon (op. cit.:384). According to Firschein (1954:55), Syrrhophus smithi and S. petrophilus have elongate lumbar glands shaped like those in Tomodactylus. Tomodactylus saxatilis resembles macrotympanum, smithi and petrophilus more than it does other species; all four attain large maximal sizes, and have lumbar glands, mostly smooth ventral surfaces, three palmar tubercles (sometimes absent in saxatilis), and usually contrasting dorsal patterns (reduced to flecks and spots in all species except saxatilis). Tomodactylus saxatilis differs from macrotympanum in having an extensive marbled dorsal pattern and a small tympanum, and differs from smithi and petrophilus in having a marbled dorsal pattern and the tips of the outer two fingers widened and truncate. Tomodactylus saxatilis differs from all other named species of Syrrhophus in having conspicuous lumbar glands and in lacking inguinal glands.