page_title: Cocinetas Basin
section_title: Paleontology
hierarchical_section_title: Cocinetas Basin / Paleontology
caption_attribution_description: English: Dalatias licha (Kitefin shark) jaw. Italiano: Mandibola di Dalatias licha.
context_page_description: The Cocinetas Basin is a small sedimentary basin of approximately 1,000 square kilometres in northeasternmost Colombia. The onshore pull-apart basin is located in the department of La Guajira at the border with Zulia, Venezuela. The basin is bound by three sets of hills; the Serranía de Jarara, Serranía Macuira and Serranía Cocinas, with the eastern boundary formed by the Gulf of Venezuela, part of the Caribbean Sea.
  The basin was formed during the Paleogene as a result of the eastward movement of the Caribbean Plate along the northern edge of the South American Plate, leading to the deposition of a Middle Eocene to Middle Pleistocene sedimentary sequence of conglomerates, sandstones, siltstones, limestones and mudstones.
  In the Cocinetas Basin, several fossiliferous stratigraphic units have been registered, providing an abundance of marine and continental vertebrate and invertebrate fossil fauna assemblages.
context_section_description: The Cocinetas Basin has provided several new species and genera of vertebrates and invertebrates of which many are still studied in detail. 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. This succession shows a broad pattern of changing depositional environments associated with the tectonic history of the Cocinetas Basin. Paleobathymetric and paleoenvironmental analyses suggest that the lower Uitpa Formation accumulated in water depths ranging from 100 to 200 metres (330 to 660 ft), a deepening with respect to the underlying Siamaná Formation and leading to the collapse of coral reefs. This contrasts with an observed increase in sediment supply for the San Luis coral-reef ecosystems in the northwestern Falcón Basin.
  The Castilletes turtle fauna shares two taxa with the Middle Miocene La Venta Fauna (Chelus colombiana and Chelonoidis sp.), and one taxon with the Late Miocene of the Urumaco Formation and Western Amazonia areas. At least two hypotheses can be proposed to explain the early to middle Miocene geographical distribution of turtles in tropical South America. The first is based on the existence of the Pebas wetland system during the Middle Miocene, which could have served as a route for the dispersion of taxa facilitated by the connectivity between major and minor drainages, even with potential interruptions to this system due to the increasing uplifting of the Eastern Ranges of Colombia. Alternatively, the geographical distribution of tropical South American turtles during the Miocene can be explained as a relict of an extensive distribution reached during the Eocene or Oligocene and modified subsequently by the uplifting of the Andes and the changes in the pattern of the main river systems.
  The occurrence of Purussaurus and Mourasuchus in the early Middle Miocene Patajau and Kaitamana beds of the Castilletes Formation represent early records for lineages previously known from younger Laventan and Huayquerian faunas. These records expand the temporal range of high diversity gavialoid-caimanine assemblages into the early Middle Miocene. The Castilletes Formation record also expands the geographic range of Miocene endemic crocodilian faunas to latitudes equivalent to those of Central America. 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.
  The sloths from the Late Pliocene Ware Formation are represented by 12 specimens that belong to 5 taxa from the 4 families of ground sloths. 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. The registered giant capybara Hydrochoeropsis wayuu is the northernmost South American Pliocene hydrochoerine record and the nearest to the Panamanian bridge. The presence of this hydrochoerine, together with the fluvio-deltaic environment of the Ware Formation, suggests that during the Late Pliocene, the environment that dominated the Guajira Peninsula was more humid and with permanent water bodies, in contrast with its modern desert habitats.
caption: The Uitpa Formation provided fossils of the kitefin shark (Dalatias licha)
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