make a mating call. It has a karyotype of 2n= 20. Similar species It is easily told apart from most species of Craugastor which occur in the same region by the head being broader than long. The most similar species are C. megacephalus and C. gulosus, but both are much larger species. C. opimus from South America is also very similar, but does not occur sympatrically. Distribution 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. rugosus two specimens which were collected at what the Americans called "Tuli Creek" in 1916 (the Tule River in south of San Miguelito in Río San Juan Department), are still labelled as such, also kept at the MCZ, and the MCZ furthermore has a specimen said to be collected in 1992 at the Escondido River near Bluefields in Nicaragua. It is seen in Costa Rica in the Carara National Park, the Fila Chonta mountains, the Osa Peninsula and in the harbour town of Quepos, all in Puntarenas Province. Ecology 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 to above sea level. It is likely an ambush predator which generally preys on beetles, but may also attack lizards and other frogs. Conservation