Journal of Molecular Evolution

, Volume 66, Issue 5, pp 533–538

Ancient DNA Clarifies the Evolutionary History of American Late Pleistocene Equids

Authors

    • Université de Lyon, Paleogenetics and Molecular Evolution, Institut de Génomique Fonctionnelle de LyonCNRS UMR 5242 – INRA – Université Claude Bernard Lyon I–Ecole Normale Supérieure de Lyon
  • Dean Male
    • Australian Centre for Ancient DNA (ACAD), School of Earth and Environmental SciencesUniversity of Adelaide
  • Maria Teresa Alberdi
    • Departamento de PaleobiologíaMuseo Nacional de Ciencias Naturales, CSIC
  • Jose Luis Prado
    • INCUAPA, Departamento de ArqueologíaUniversidad Nacional del Centro Del Valle
  • Alfredo Prieto
    • Centro de Estudios del Cuaternario, Instituto de la PatagoniaUniversidad de Magallanes
  • Alan Cooper
    • Australian Centre for Ancient DNA (ACAD), School of Earth and Environmental SciencesUniversity of Adelaide
  • Catherine Hänni
    • Université de Lyon, Paleogenetics and Molecular Evolution, Institut de Génomique Fonctionnelle de LyonCNRS UMR 5242 – INRA – Université Claude Bernard Lyon I–Ecole Normale Supérieure de Lyon
Article

DOI: 10.1007/s00239-008-9100-x

Cite this article as:
Orlando, L., Male, D., Alberdi, M.T. et al. J Mol Evol (2008) 66: 533. doi:10.1007/s00239-008-9100-x

Abstract

Hippidions are past members of the equid lineage which appeared in the South American fossil record around 2.5 Ma but then became extinct during the great late Pleistocene megafaunal extinction. According to fossil records and numerous dental, cranial, and postcranial characters, Hippidion and Equus lineages were expected to cluster in two distinct phylogenetic groups that diverged at least 10 MY, long before the emergence of the first Equus. However, the first DNA sequence information retrieved from Hippidion fossils supported a striking different phylogeny, with hippidions nesting inside a paraphyletic group of Equus. This result indicated either that the currently accepted phylogenetic tree of equids was incorrect regarding the timing of the evolutionary split between Hippidion and Equus or that the taxonomic identification of the hippidion fossils used for DNA analysis needed to be reexamined (and attributed to another extinct South American member of the equid lineage). The most likely candidate for the latter explanation is Equus (Amerhippus) neogeus. Here, we show by retrieving new ancient mtDNA sequences that hippidions and Equus (Amerhippus) neogeus were members of two distinct lineages. Furthermore, using a rigorous phylogenetic approach, we demonstrate that while formerly the largest equid from Southern America, Equus (Amerhippus) was just a member of the species Equus caballus. This new data increases the known phenotypic plasticity of horses and consequently casts doubt on the taxonomic validity of the subgenus Equus (Amerhippus).

Supplementary material

239_2008_9100_MOESM1_ESM.pdf (651 kb)
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Copyright information

© Springer Science+Business Media, LLC 2008