Neogene sloth assemblages (Mammalia, Pilosa) of the Cocinetas Basin (La Guajira, Colombia): implications for the Great American Biotic Interchange

59 4 July 563 582 10.1111/pala.12244

AMSON, E., CARRILLO, J.D., JARAMILLO, C. 2016. Neogene sloth assemblages (Mammalia, Pilosa) of the Cocinetas Basin (La Guajira, Colombia): implications for the Great American Biotic Interchange. Palaeontology, 59, 4, 563-582. DOI: 10.1111/pala.12244

Eli Amson, Juan D. Carrillo, and Carlos Jaramillo
  • Eli Amson - Smithsonian Tropical Research Institute Balboa‐Ancon Panama (Email: eli.amson@hu-berlin.de)
  • Eli Amson - Paläontologisches Institut und Museum der Universität Zürich Zürich Switzerland
  • Juan D. Carrillo - Paläontologisches Institut und Museum der Universität Zürich Zürich Switzerland (Email: juan.carrillo@pim.uzh.ch)
  • Carlos Jaramillo - Smithsonian Tropical Research Institute Balboa‐Ancon Panama (Email: jaramilloc@si.edu)
  • Manuscript Accepted: 08 May 2016
  • Manuscript Received: 19 February 2016
Smithsonian Tropical Research Institute Alexander von Humboldt Foundation Swiss National Fund. Grant Number: SNF 31003A‐149605 Smithsonian Institution National Geographic Society Anders Foundation Gregory D. and Jennifer Walston Johnson Universidad del Norte Lab of M. R. Sánchez‐Villagra at the Paläontologisches Institut und Museum der Universität Zürich. Grant Number: EAR 0957679 National Science Foundation

We describe sloth assemblages from the Cocinetas Basin (La Guajira peninsula, Colombia), found in the Neogene Castilletes and Ware formations, located in northernmost South America, documenting otherwise poorly known biotas. The tentative referral of a specimen to a small megatherioid sloth, Hyperleptus?, from the early–middle Miocene Castilletes Formation, suggests affinities of this fauna with the distant Santa Cruz Formation and documents a large latitudinal distribution for this taxon. The late Pliocene Ware Formation is much more diverse, with five distinct taxa representing every family of ‘ground sloths’. This diversity is also remarkable at the ecological level, with sloths spanning over two orders of magnitude of body mass and probably having different feeding strategies. Being only a few hundred kilometres away from the Isthmus of Panama, and a few hundred thousand years older than the classically recognized first main pulse of the Great American Biotic interchange (GABI 1), the Ware Formation furthermore documents an important fauna for the understanding of this major event in Neogene palaeobiogeography. The sloths for which unambiguous affinities were recovered are not closely related to the early immigrants found in North America before GABI 1.

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