Rugose Robber Frog

These are relatively big rain frogs with a large head (females to 69 mm (2.7 in) in snout–vent length, males to 44 mm (1.7 in)). The eyes have a black iris and the upper eyelid is covered in warts and bumps. There are crests just behind the eyes. The dorsum (back) is covered in warts and the creature appears much like a toad. There are hourglass-shaped ridges on the upper back, these are lined in lighter coloured stripes. There is no webbing between the digits of the limbs. The dorsum is dark brown, dark grey, or black in colour. The ventral surface of the animal is mottled brown with white and red. The ventral surfaces of the thighs may be either yellowish or orange. The inner thighs are ornamented with alternating bars of black and bright scarlet red; the black bars continue to the dorsal surface of the thighs. The groin has bright white and black marks. The juveniles are coloured differently than the adults: the dorsal warts are tipped in white at first but darken with age, the inner thighs are barred with white and black, and the ventral surfaces of the legs and groin are orange-red. According to Noble, it has a noticeably thicker and more robust stomach wall than other species of Eleutherodactylus (now split into Craugastor and other genera), but he was dissecting a mix of different species, mostly C. megacephalus, in order to describe C. …

Although the distribution of this species at present is believed to be mostly restricted to eastern Costa Rica, initially it was in fact believed not to occur in this country and to exist in two disjunct populations in Nicaragua and Panama, this situation persisting until at least 1923 (fide Fritz Nieden). According to Savage (2002) and Frost (2015), Craugastor rugosus is now found on the slopes and lowlands facing the Pacific from the downstream region of the Rio Carara in Costa Rica southwards to the southern part of far western Panama. However, it is possible that the distribution of this species in fact stretches further north and east than indicated, although the history of taxonomic confusion makes it complicated to ascertain. Henry Sterling Blair collected a specimen for the Museum of Comparative Zoology (MCZ) at Harvard University in Zent, Limón Province, Costa Rica, in 1996. During the time Nicaragua was occupied by the USA, of the 31 specimens formerly thought to be C. …

This frog can be found in humid and hot tropical lowland rainforests, moist premontane forest, secondary forest, plantations and heavily altered former forest habitats. It is usually found amongst the leaf litter of the forest. It has been seen hopping on the forest floor during the day. According to Savage (2002) it is found at altitudes from 10 m (33 ft) to 1,220 m (4,000 ft) above sea level. It is likely an ambush predator which generally preys on beetles, but may also attack lizards and other frogs.