An upper eocene frog from the dominican republic and its implication for Caribbean biogeography

Area of Science:

• Paleontology
• Vertebrate Zoology
• Paleobiogeography

Background:

• Amphibian fossils provide crucial insights into evolutionary history and past ecosystems.
• Amber inclusions preserve delicate biological structures, offering unique windows into ancient life.
• The fossil record of Mesoamerica, particularly from the Eocene epoch, is sparse.

Purpose of the Study:

• To describe a newly discovered frog fossil preserved in Eocene Dominican amber.
• To establish the oldest complete lissamphibian fossil record for Mesoamerica.
• To infer the composition of Antillean fauna during the Eocene and its biogeographic implications.

Main Methods:

• Geological dating of the amber matrix to determine its Eocene age.
• Detailed morphological analysis of the preserved amphibian fossil.
• Comparative osteology and phylogenetic placement of the fossil within the Eleutherodactylus genus.

Main Results:

• Identification of a leptodactylid frog, genus Eleutherodactylus, within Eocene amber.
• This represents the first amphibian fossil found in amber and the oldest complete lissamphibian from Mesoamerica.
• The amber's dating indicates a diverse Antillean fauna existed by the late Eocene, earlier than previously thought.

Conclusions:

• The discovery pushes back the known timeline for diverse amphibian life in the Antilles.
• This fossil, alongside other amber finds, suggests Tertiary landmass movements significantly shaped current species distribution.
• The findings underscore the importance of amber fossils in reconstructing Neotropical paleobiogeography.