Description

Bufo fastidiosus is a small toad, with males ranging from 43-52 mm and females from 40-60 mm. Its head is wider than it is long, and the skin on the upper surface of the head is co-ossified to the skull. The eyes are of moderate size and the iris is brown. The tympanum and middle ear are lacking. This toad has massive, elevated, light-colored canthal, supraorbital, postorbital, and bulbous supratympanic cranial crests. In contrast, the parietal crest is weak. The parotoid gland is smooth and oblong, and its size is about two-thirds the area of the eyelid. There is a well-developed broad temporal plate which exhibits exostosis (bony growth) continuous with the supratympanic crest. Dorsal surfaces have large and small smooth warts and a single distinct series of smooth lateral warts. The venter is strongly tuberculate. The upper surface of the tibial segment has massive pointed warts. Limbs are short, especially the hind limbs. The hands and feet have fleshy pads with webbed fingers and toes, and they lack definite subarticular, accessory palmar, or plantar tubercles. Finger II is longer than finger I. The inner metatarsal tubercle is elliptical, the outer tubercle is elongate and larger than the inner, and no tarsal fold is present (Savage 2002).

The dorsal ground color of adult toads is brown to black, nearly uniform in color or with red, rusty, or pink warts and tubercles. A light mid-dorsal stripe is usually present; there are no transverse dark limb bars. Ventral coloration is brown to black and mottled with lighter pigments (Savage 2002).

Males have no vocal slits or sacs. They lack an advertisement call but do have a weak release trill. Adult males have hypertrophied forelimbs and a discrete light nuptial pad on the thumb (Savage 2002).

Bufo fastidiosus larvae are small, reaching a total length of 15.99 mm at stage 36. The body is ovoid and the mouth is anteroventral. The snout is rounded in a dorsal outline and directed dorsolaterally. Nostrils and eyes are dorsal with the nostrils slightly closer to eyes than snout tip. The spiracle is lateral and sinistral, and the vent tube is medial. The tail and fins are moderate in size, with a small caudal fin that is subovoid to round at the tip. The larval oral disk is medium and emarginated. Beaks and 2/3 rows of denticles are present. The upper jaw sheath is moderately wide and finely serrated, with the medial section forming a straight line and the lateral processes abruptly tapering posterolaterally. The lower jaw sheath is about equal in width to the upper, also finely serrate, and strongly V-shaped. Body coloration is a uniform chocolate brown, with a dark gray venter. Caudal musculature is dark olive brown, and the fins are a translucent olive brown with dark speckles. (Lips and Krempels 1995)

A Spanish-language species account can be found at the website of Instituto Nacional de Biodiversidad (INBio).