A mitogenomic timetree for Darwin’s enigmatic South American mammal Macrauchenia patachonica

Michael Westbury (1) , Sina Baleka (1) , Axel Barlow (1) , Stefanie Hartmann (1) , Johanna L.A. Paijmans (1) , Alejandro Kramarz (2) , Analía Forasiepi (2) , Mariano Bond (2) , Javier Gelfo (2) , Marcelo Reguero (2) , Patricio López-Mendoza , Matias Taglioretti , Fernando Scaglia , Andrés Rinderknecht , Washington Jones , Francisco Mena , Guillaume Billet (3) , Christian de Muizon (3) , José Luis Aguilar , Ross D.E. Macphee (4) , Michael Hofreiter (1)

1 University of Potsdam = Universität Potsdam
2 CONICET - Consejo Nacional de Investigaciones Científicas y Técnicas [Buenos Aires]
3 CR2P - Centre de Recherche en Paléontologie - Paris
4 AMNH - American Museum of Natural History [New York, USA] = Musée américain d'histoire naturelle [New York, USA]

The unusual mix of morphological traits displayed by extinct South American native ungulates (SANUs) confounded both Charles Darwin, who first discovered them, and Richard Owen, who tried to resolve their relationships. Here we report an almost complete mitochondrial genome for the litoptern Macrauchenia. Our dated phylogenetic tree places Macrauchenia as sister to Perissodactyla, but close to the radiation of major lineages within Laurasiatheria. This position is consistent with a divergence estimate of B66 Ma (95% credibility interval, 56.64-77.83 Ma) obtained for the split between Macrauchenia and other Panperissodactyla. Combined with their morphological distinctiveness, this evidence supports the positioning of Litopterna (possibly in company with other SANU groups) as a separate order within Laurasiatheria. We also show that, when using strict criteria, extinct taxa marked by deep divergence times and a lack of close living relatives may still be amenable to palaeogenomic analysis through iterative mapping against more distant relatives.

Domaines: Paléontologie; Evolution [q-bio.PE]; Systématique, phylogénie et taxonomie

Michael Westbury, Sina Baleka, Axel Barlow, Stefanie Hartmann, Johanna L.A. Paijmans, et al.. A mitogenomic timetree for Darwin’s enigmatic South American mammal Macrauchenia patachonica. Nature Communications, 2017, 8, pp.15951. ⟨10.1038/ncomms15951⟩. ⟨hal-02612082⟩