canton of Buenos Aires in Puntarenas Province of the southern Pacific zone of Costa Rica, from one G. K. Cherrie. Unfortunately the type specimen for this taxon is lost (fide Savage and Myers (2002)). Albert Günther, working in Britain, moved this new taxon to Hylodes a few years later, in 1900, and produced the first comprehensive check-lists for the countries of the region. At this time, H. rugosus was only known from Panama and Nicaragua, but suspected to occur in Costa Rica, whilst H. megacephalus, a frog also named by Cope from Costa Rica, was commonly considered extant here, and H. florulentus was still known from Cope's single specimen from the eastern highlands. According to Günther, H. pelviculus was a synonym of H. megacephalus. Thus, by the turn of the previous century what is presently (2019) understood as this frog species consisted of two taxa and one mixed taxon, and in 1904 the Norwegian herpetologist Leonhard Stejneger moved them all to the genus Eleutherodactylus. In the second half of 1916, during the United States occupation of Nicaragua and in the midst of an anti-imperialist civil war, an American herpetological and ichthyological expedition was mounted to obtain new specimens for US museums. As such, the expedition members returned without incident by early the next year, and the Harvard student Gladwyn Kingsley Noble set about describing the amphibians amongst their many collections. A series of thirty-one specimens were ascribed by him to belong to this taxon. He concluded that E. rugosus was simply the immature form of what was hereto known as E. megacephalus, believing that the darker colour of E. rugosus would lighten to that of E. megacephalus (in this collection there were some small individuals with light colour, but Noble does not explain this), and that the lack of cranial crest ornamentation in specimens previously identified as E. rugosus was simply a due to immaturity: according to him larger specimens of E. rugosus showed developing crests. As E. rugosus was the older name, and E. megacephalus the junior synonym, Noble considered E. rugosus the correct name, although it appears that many later authors preferred Cope's E. megacephalus. Noble agreed with Günther in that E. pelviculus was a synonym of E. megacephalus, and also mentioned the possible synonymy of yet another Cope taxon, E. gulosus - a rare, curiously large taxon only known at the time from the initial collection, although