Tinamous are stocky terrestrial birds with very short tails and rounded wings. Tepui Tinamou is a medium-sized, dark, plain looking tinamou with a pale eye. The upperparts and upperwing are entirely sooty chestnut, while the face and sides of the head are sooty gray. The breast is tinged with rufous. The rest of underparts are slightly paler and generallt grayer. Sexes alike.
Tepui Tinamou may overlap with Little Tinamou (Crypturellus soui), but Little Tinamou is smaller, paler, and has a dark iris. Cinereous Tinamou (Crypturellus cinereus) is restricted to lower elevations, is sooty gray, lacking the chestnut tones of Tepui Tinamou, and has a dark iris. Red-legged Tinamou (Crypturellus erythropus) has red tarsi, barred upperparts, and is browner overall.
The following description is based on Zimmer and Phelps (1945) and on Blake (1977):
Adult: Sexes similar. Upperparts (including crown) rufescent chestnut brown; sides of neck and of breast more or less strongly tinged with rufous. Sides of head and throat sooty gray to dull grayish slate. Lower breast, belly and undertail coverts dark smoky brown, tinged rufescent.
Iris: cream, creamy white
Bill: maxilla black, mandible yellow with black tip
Tarsi and toes: olive
Bare parts color data from Zimmer and Phelps (1945) and Blake (1977).
Total length: 28-30.5 cm (Hilty 2003), 28.5-30 cm (Blake 1977)
Linear measurements (from Blake 1977):
male (n = 3)
wing length (flat): mean 144.5 mm (range 143.5-146 mm)
bill length (exposed culmen): mean 23.6 mm (range 22.5-25 mm)
tarsus length: 52 mm (n = 1; Zimmer and Phelps 1945)
female (n = 1)
wing length (flat): 153 mm
bill length (exposed culmen): 24 mm