Total evidence tip-dating phylogeny of platyrrhine primates and 27 well-justified fossil calibrations for primate divergences

Phylogenies with estimates of divergence times are essential for investigating many evolutionary questions. In principle, "tip-dating" is arguably the most appropriate approach, with fossil and extant taxa analyzed together in a single analysis, and topology and divergence times estimated simultaneously. However, "node-dating" (as used in many molecular clock analyses), in which fossil evidence is used to calibrate the age of particular nodes a priori, will probably remain the dominant approach, due to various issues with analyzing morphological and molecular data together. Tip-dating may nevertheless play a key role in robustly identifying fossil taxa that can be used to inform node-dating calibrations. Here, we present tip-dating analyses of platyrrhine primates (so-called "New World monkeys") based on a total evidence dataset of 418 morphological characters and 10.2 kb of DNA sequence data from 17 nuclear genes, combined from previous studies. The resultant analyses support a late Oligocene or early Miocene age for crown Platyrrhini (composite age estimate: 20.7-28.2 Ma). Other key findings include placement of the early Miocene putative cebid Panamacebus outside crown Platyrrhini, equivocal support for Proteropithecia being a pitheciine, and support for a clade comprising three subfossil platyrrhines from the Caribbean (Xenothrix, Antillothrix and Paralouatta), related to Callicebinae. Based on these results and the available literature, we provide a list of 27 well-justified node calibrations for primate divergences, following best practices: 17 within Haplorhini, five within Strepsirrhini, one for crown Primates, and four for deeper divergences within Euarchontoglires. In each case, we provide a hard minimum bound, and for 23 of these we also provide a soft maximum bound and a suggested prior distribution. For each calibrated node, we provide the age of the oldest fossil of each daughter lineage that descends from it, which allows use of the "CladeAge" method for specifying priors on node ages.