Edalorhina perezi is a toad-like South American frog with an appearance similar to that of a dead leaf. Snout-vent length ranges from 24 - 37 mm, with females being larger than the males (Deichmann et al. 2008). The snout is rounded, often with a cone shaped tubercle at the tip. Its tympanum is oval, with a length about the same as the eye. Above the eye sit several dermal protrusions (“horns”), which look similar to eyelashes. A dermal fold runs from behind the eye to the hind leg insertions, and gives E. perezi a flat, leaf-like appearance when viewed form above (Cope 1874). Vomerine teeth are either poorly developed or absent. Toes are slightly webbed (Dunn 1949).
Tadpoles hatch at stage 25 with a body length of around 4.1 mm and a total length of around 10.5 mm. The body is robust and wider than it is deep. Snout is rounded, eyes are located dorsolaterally. The mouth is anteroventrally oriented. The caudal fins are equal in depth to the tail musculature and each other. Tail tip is rounded (Schlüter 1990). Two upper and two lower rows of denticles are present. The tadpoles do not have external gills or adhesive organs. Tadpoles at stage 41 have a body length of 10.1 - 10.2 mm and a total length of 27.1 - 27.9 mm (Duellman and Morales 1990).
Adult E. perezi can be distinguished from its sister taxon E. nasuta by the shape and characters of the head. E. perezi has a short, rounded snout and very prominent tubercles on the upper eyelid, while E. nasuta has a long, pointed, fleshy snout and less pronounced eyelid tubercles (Duellman and Morales 1990).
The dorsum and dorsal surfaces of the limbs may be blotched or striped brown, while the venter is white with black bands and spots. The sides of the body are black. Bright yellow coloration may be seen on the undersides and insertions of the limbs (Cope 1874).
Dorsal skin texture and ventral color pattern vary geographically. The dorsum may be smooth, have 4-5 tubercles, have many tubercles, or have paired dermal ridges running down the back. The venter can range from mostly white with black present laterally to all black other than a white throat with black flecks (Duellman and Morales 1990). Vomerine teeth and an interocular dermal ridge may also be present or absent depending on location. Development of a wart on the snout also varies between individuals (Dunn 1949).
Edalorhina perezi tadpoles are light brown with darker brown mottling on their top and sides (Schlüter 1990).
The species authority for E. perezi is Don Marcos Jiménez de la Espada, 1871.
Edalorhina perezi is synonymous with Bubonias plicifrons (Cope, 1874) and E. buckleyi (Boulenger, 1882). Edalorhina perezi was distinguished based on characters such as wart organization and vomerine teeth, which are now considered to be variation within a single species (Dunn 1949).
Edalorhina perezi is the sister taxon to E. nasuta, the only other member of Edalorhina. The closest relatives of the genus,Edalorhina, are the genera Physalaemus and Pleurodema (Lourenço et al. 2000).
Edalorhina perezi has a diploid number of 2n=22 (Lourenço et al. 2000).