A Review on Xenarthran Molecular Phylogenetics Published in "The Biology of the Xenarthra"

In the last 20 years the reconstruction of xenarthran phylogenetic relationships has been revolutionized by molecular data. Earlier phylogenies relied on morphological, cytological, immunological, and protein characters, but more recent attempts have benefited from the sequencing of mitochondrial and nuclear genes. In this chapter, we review the recent advances made in xenarthran molecular systematics. Molecular data have allowed reconstruction of a phylogeny of Xenarthra at the genus level, with the recognition of the clades Pilosa, Folivora, Vermilingua, Cingulata, and Tolypeutinae + Euphractinae, but left uncertain the position of Xenarthra within placental mammals. This phylogenetic framework subsequently has been used to define a molecular timescale for the evolutionary history of extant xenarthrans, suggesting the potential influence of Tertiary climate change on this endemic South American order. Future phylogenetic work on Xenarthra includes resolving their relationship to other placental groups using genomic data and the reconstruction of a comprehensive species-level phylogeny. Coupled with phylogeographic studies at the population level, this will allow further characterization of the genetic diversity of this peculiar placental order and provide guidance to conservation plans for its endangered species.

Reference: Delsuc F. & Douzery E.J.P. (2008). Recent advances and future prospects in xenarthran molecular phylogenetics. Pp. 11-23. In The Biology of the Xenarthra edited by S.F. Vizcaíno & W.J. Loughry. University Press of Florida, Gainesville, FL.