Notiomastodon Supplemental Data

The extinct Gomphotheriidae is the only proboscidean family that colonized
South America. The phylogenetic position of the endemic taxa has been through
several revisions using morphological comparisons. Morphological studies are
enhanced by paleogenetic analyses, a powerful tool to resolve phylogenetic rela-
tionships; however, ancient DNA (aDNA) preservation decreases in warmer re-
gions. Despite the poor preservation conditions for aDNA in humid, sub-tropical
climates, we recovered ~3,000 bp of mtDNA of Notiomastodon platensis from
the Arroyo del Vizcaı́no site, Uruguay. Our calibrated phylogeny places Notio-
mastodon as a sister taxon to Elephantidae, with a divergence time of ~13.5
Ma. Additionally, a total evidence analysis combining morphological and paleoge-
netic data shows that the three most diverse clades within Proboscidea diverged
during the early Miocene, coinciding with the formation of a land passage be-
tween Africa and Eurasia. Our results are a further step toward aDNA analyses
on Pleistocene samples from subtropical regions and provide a framework for
proboscidean evolution.