The earliest record of Caribbean frogs: a fossil coquí from Puerto Rico

Abstract

The nearly 200 species of direct-developing frogs in the genus Eleutherodactylus (the Caribbean landfrogs, which include the coquís) comprise an important lineage for understanding the evolution and historical biogeography of the Caribbean. Time-calibrated molecular phylogenies provide indirect evidence for the processes that shaped the modern anuran fauna, but there is little direct evidence from the fossil record of Caribbean frogs about their distributions in the past. We report a distal humerus of a frog from the Oligocene (approx. 29 Ma) of Puerto Rico that represents the earliest known fossil frog from any Caribbean island. Based on its prominent rounded distal humeral head, distally projecting entepicondyle, and reduced ectepicondyle, we refer it to the genus Eleutherodactylus . This fossil provides additional support for an early arrival of some groups of terrestrial vertebrates to the Greater Antilles and corroborates previous estimates based on molecular phylogenies suggesting that this diverse Caribbean lineage was present in the islands by the mid-Cenozoic.

3D models related to the publication: Early Oligocene chinchilloid caviomorphs from Puerto Rico and the initial rodent colonization of the West Indies

“…This find has also raised the critical question of a possible link between these Oligocene Puerto Rican chinchilloids and some of the "giant hutias" (Amblyrhiza Cope, 1868 and Elasmodontomys Anthony, 1916), for which a chinchilloid status is also strongly supported in the framework of that study (Marivaux et al, 2020). Although the pre-Pleistocene evolutionary history of these endemic "giant hutias" remains so far undocumented, lineages of these iconic recently-extinct rodents could have a very great antiquity on the islands, extending back more than 30 million years (as also recently demonstrated for West Indian sloths and coquí frogs; Delsuc et al, 2019;Presslee et al, 2019;Blackburn et al, 2020).…”

Eocene intra-plate shortening responsible for the rise of a faunal pathway in the northeastern Caribbean realm

“…Darwin [ 1 ] already recognized that the West Indies (Greater Antilles, Bahamas, and Lesser Antilles) appear to have been colonized by South American terrestrial mammal faunas. By now, paleontological findings of chinchilloid rodents [ 2 , 3 ] and eleutherodactylids [ 4 ] have identified that part of this colonization occurred in late Eocene to early Oligocene times (∼40–30 Ma). This is consistent with relaxed molecular clock constraints from terrestrial faunal elements from the Caribbean such as sloths (recently extinct [ 5 , 6 ]) and spiders [ 7 ], amphibians such as eleutherodactylid frogs and bufonids [ 8 , 9 ], and freshwater aquatic organisms such as cichlids [ 10 , 11 ].…”

Two‐hundred million years of anuran body‐size evolution in relation to geography, ecology and life history

“…(2018). Fossil data were gathered from Sanchiz (1998), Tietje and Rödel (2018), and Blackburn, Keeffe, Vallejo‐Pareja, and Vélez‐Juarbe (2020). We collected development mode records (whether a species completes metamorphosis within an egg (direct development), has a free‐swimming larval phase (larval development), or completes metamorphosis within the body of the parent (viviparous development)) from secondary references (Lannoo, 2005; Gomez‐Mestre et al., 2012; AmphibiaWeb 2017; IUCN, 2017) and the AmphiBIO database (Oliveira et al., 2017).…”