Otophryne pyburni is a small frog; adult females can grow to 61 mm in SVL, while the males can reach 55 mm (Campbell and Clarke, 1998). This frog has a broad body, short legs, and a broad, triangular head with a sharp-pointed snout projecting well past the lower jaw. Nostrils are elongated and protruding. The tympanum is large and distinct. A supratympanic groove is present, extending from the posterior of the eye nearly to the forelimb. The pupils are round, with the upper third of the iris pale bronze and the lower part dark brown. The tongue is broad and oval-shaped, and is attached at the anterior but free at the posterior. No vomerine teeth are present. Choanae are large and oval-shaped. The body is robust, with an inguinal fold of skin between the thigh and the side of the body. Fingers have rounded and slightly expanded tips, without webbing; the relative finger lengths are 3>4>2>1. Palmar tubercles are present on the hand as well as subarticular tubercles. Toe tips are rounded but not dilated, and the relative length of the toes is 4>3>5>2>1. Some toes have lateral keeling but no fringe is present. Reduced webbing is present between the toes. A glandular ridge is present on the lower surface of the shank, developing into a series of tubercles across the metatarsus and heel. Subarticular tubercles are low and rounded on the foot (Campbell and Clarke, 1998).
The dorsum can be reddish brown to grayish yellow or gray-brown and may be uniform in color, or patterned with darker streaks and a dark mid-dorsal stripe (Wassersug and Pyburn, 1987; Campbell and Clarke, 1998). A pale irregular stripe runs from the snout across the canthus to the eye and the top of the tynpanum, continuing along the side of the body. Below the stripe, the side of the body is dark brown. The sides of the head and the lower parts of the limbs are also dark brown, while the upper parts of the limbs are lighter and the same color as the dorsum. The throat is generally dark brown with pale speckles, with the chest also speckled but somewhat lighter brown, and the abdomen a pale cream to orange color. Some females may have a pale throat, and females also usually have a broader lateral pale stripe. The lower surface of the hindlimbs and feet are orange. Generally there are raised, cream-colored bumps present on the dorsum and the limbs (Campbell and Clarke, 1998).
This frog blends well into leaf litter, having been described as resembling a "pinnately veined dead leaf" (Wassersug and Pyburn, 1987). It is capable of metachrosis, with reddish individuals able to become brown to grayish brown, and yellow individuals changing to yellow-gray (Wassersug and Pyburn, 1987).
This species was first described by Campbell and Clarke (1998), and is named for William F. Pyburn.