In the Cocinetas Basin, several fossiliferous stratigraphic units have been registered, providing an abundance of marine and continental vertebrate and invertebrate fossil fauna assemblages.

The Uitpa, Jimol, Castilletes and Ware Formations contain numerous fossils of Neogene and Quaternary ages, both before and after the Great American Biotic Interchange (GABI), presenting new insights in the understanding of the variation in South American fauna related to the uplift of the Panama Block and the connection of North America and South America.

[3] In 2015, Moreno et al. revised the stratigraphy of the basin in detail, redefining ages based on extensive fieldwork, biostratigraphy and 87Sr/86Sr isotope ratios.

[25] The marine invertebrate fauna of the Ware Formation shows a greater similarity with modern assemblages offshore of the Guajira Peninsula than with those of the underlying units.

[26] The base of the Ware Formation was deposited in a fluvio-deltaic environment, whereas the marine invertebrate assemblage at the top of the unit contains taxa typical of exposed open-ocean shoreface and nearshore settings, but with proximity to coral reef habitats.

[30] Shortly after deposition, during the Early Oligocene, the Macarao Formation was heavily deformed, creating the series of hills that today still surround the Cocinetas Basin.

[28] The transtensional phase of the Early Oligocene was followed by the deposition of the unconformably overlying Siamaná Formation, characterised by a basal sequence of conglomerates, indicating tectonic uplift in the provenance areas, followed by reefal limestones rich in corals and algae.

[30] The end of the Neogene corresponded to a marine platform setting, interrupted by the presence of a series of highs; the present-day mountain ranges of the region.

The Uitpa, Jimol, Castilletes, and Ware Formations preserve both a diverse continental vertebrate and a rich marine invertebrate fossil record that documents paleoenvironmental change through the Neogene.

The Castilletes Formation record also expands the geographic range of Miocene endemic crocodilian faunas to latitudes equivalent to those of Central America.

[41] The connections between hydrographic basins and the development of mega-wetland systems in equatorial South America allowed the long persistence of several lineages over an extensive geographical range.

The extinction of gavialoids and specialized caimanines in equatorial South America was likely caused by the isolation and aridification of peripheral basins, together with the disappearance of mega-wetlands.

Their body sizes span over two orders of magnitude, and they most likely featured various feeding strategies, documenting a highly diverse assemblage of sloths from the Neotropics.

Although geographically close to the Isthmus of Panama, and temporally preceding the first phase of the Great American Biotic Interchange by only 200,000 to 400,000 years, the sloths for which unambiguous affinities were recovered are not closely related to the early immigrants found in North America before the first main pulse of the Great American Biotic interchange.

[43] The registered giant capybara Hydrochoeropsis wayuu is the northernmost South American Pliocene hydrochoerine record and the nearest to the Panamanian bridge.