The platyrrhine primates, or New World monkeys, are immigrant mammals whose fossil record comes from Tertiary and Quaternary sediments of South America and the Caribbean Greater Antilles. The time and place of platyrrhine origins are some of the most controversial issues in primate palaeontology, although an African Palaeogene ancestry has been presumed by most primatologists. Until now, the oldest fossil records of New World monkeys have come from Salla, Bolivia, and date to approximately 26 million years ago, or the Late Oligocene epoch. Here we report the discovery of new primates from the ?Late Eocene epoch of Amazonian Peru, which extends the fossil record of primates in South America back approximately 10 million years. The new specimens are important for understanding the origin and early evolution of modern platyrrhine primates because they bear little resemblance to any extinct or living South American primate, but they do bear striking resemblances to Eocene African anthropoids, and our phylogenetic analysis suggests a relationship with African taxa. The discovery of these new primates brings the first appearance datum of caviomorph rodents and primates in South America back into close correspondence, but raises new questions about the timing and means of arrival of these two mammalian groups.

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The unparalleled biodiversity found in the American tropics (the Neotropics) has attracted the attention of naturalists for centuries. Despite major advances in recent years in our understanding of the origin and diversification of many Neotropical taxa and biotic regions, many questions remain to be answered. Additional biological and geological data are still needed, as well as methodological advances that are capable of bridging these research fields. In this review, aimed primarily at advanced students and early-career scientists, we introduce the concept of “trans-disciplinary biogeography,” which refers to the integration of data from multiple areas of research in biology (e.g., community ecology, phylogeography, systematics, historical biogeography) and Earth and the physical sciences (e.g., geology, climatology, palaeontology), as a means to reconstruct the giant puzzle of Neotropical biodiversity and evolution in space and time. We caution against extrapolating results derived from the study of one or a few taxa to convey general scenarios of Neotropical evolution and landscape formation. We urge more coordination and integration of data and ideas among disciplines, transcending their traditional boundaries, as a basis for advancing tomorrow’s ground-breaking research. Our review highlights the great opportunities for studying the Neotropical biota to understand the evolution of life.

Please cite this article as: Aristide, L., Rosenberger, A.L., Tejedor, M., Ivan Perez, S., Modeling lineage and phenotypic diversification in the New World monkey (Platyrrhini, Primates) radiation, Molecular Phylogenetics and Evolution (2013), doi: http://dx.doi.org/10. 1016/j.ympev.2013.11.008 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Adaptive radiations that have taken place in the distant past can now be more 2 thoroughly studied with the availability of large molecular phylogenies and comparative 3 data drawn from extant and fossil species. Platyrrhines are a good example of a major 4 mammalian evolutionary radiation confined to a single continent, involving a relatively 5 large temporal scale and documented by a relatively small but informative fossil record. 6 Modeling lineage and phenotypic diversification in the NewHere, we present comparative evidence using data on extant and fossil species to 7 explore alternative evolutionary models in an effort to better understand the process of 8 platyrrhine lineage and phenotypic diversification. Specifically, we compare the 9 likelihood of null models of lineage and phenotypic diversification versus various 10 models of adaptive evolution. Moreover, we statistically explore the main ecological 11 dimension behind the platyrrhine diversification. Contrary to the previous proposals, 12 our study did not find evidence of a rapid lineage accumulation in the phylogenetic tree 13 of extant platyrrhine species. However, the fossil-based diversity curve seems to show a 14 slowdown in diversification rates toward present times. This also suggests an early high 15 rate of extinction among lineages within crown Platyrrhini. Finally, our analyses support 16 the hypothesis that the platyrrhine phenotypic diversification appears to be characterized 17 by an early and profound differentiation in body size related to a multidimensional 18 niche model, followed by little subsequent change (i.e., stasis). 19

Two new fossil mammal localities from the Paleogene of central-western Patagonia are preliminarily described as the basis for a new possible biochronological unit for the early Eocene of Patagonia, correlated as being between two conventional SALMAs, the Riochican (older) and the Vacan subage of the Casamayoran SALMA. The mammal-bearing strata belong to the Middle Chubut River Volcanic-Pyroclastic Complex (northwestern Chubut Province, Argentina), of

New World monkeys (platyrrhines) are one of the most diverse groups of primates, occupying today a wide range of ecosystems in the American tropics and exhibiting large variations in ecology, morphology, and behavior. Although the relationships among the almost 200 living species are relatively well understood, we lack robust estimates of the timing of origin, ancestral morphology, and geographic range evolution of the clade. Here we integrate paleontological and molecular evidence to assess the evolutionary dynamics of extinct and extant platyrrhines. We develop novel analytical frameworks to infer the evolution of body mass, changes in latitudinal ranges through time, and species diversification rates using a phylogenetic tree of living and fossil taxa. Our results show that platyrrhines originated 5-10 million years earlier than previously assumed, dating back to the Middle Eocene. The estimated ancestral platyrrhine was small - weighing 0.4 kg - and matched the size of their presumed African ancestors. As the three platyrrhine families diverged, we recover a rapid change in body mass range. During the Miocene Climatic Optimum, fossil diversity peaked and platyrrhines reached their widest latitudinal range, expanding as far South as Patagonia, favored by warm and humid climate and the lower elevation of the Andes. Finally, global cooling and aridification after the middle Miocene triggered a geographic contraction of New World monkeys and increased their extinction rates. These results unveil the full evolutionary trajectory of an iconic and ecologically important radiation of monkeys and showcase the necessity of integrating fossil and molecular data for reliably estimating evolutionary rates and trends.

The estimation of phylogenetic relationships and divergence times among a group of organisms is a fundamental first step toward understanding its biological diversification. The time of the most recent or last common ancestor (LCA) of extant platyrrhines is one of the most controversial among scholars of primate evolution. Here we use two molecular based approaches to date the initial divergence of the platyrrhine clade, Bayesian estimations under a relaxed-clock model and substitution rate plus generation time and body size, employing the fossil record and genome datasets. We also explore the robustness of our estimations with respect to changes in topology, fossil constraints and substitution rate, and discuss the implications of our findings for understanding the platyrrhine radiation. Our results suggest that fossil constraints, topology and substitution rate have an important influence on our divergence time estimates. Bayesian estimates using conservative but realistic fossil constraints suggest that the LCA of extant platyrrhines existed at ca. 29 Ma, with the 95% confidence limit for the node ranging from 27–31 Ma. The LCA of extant platyrrhine monkeys based on substitution rate corrected by generation time and body size was established between 21–29 Ma. The estimates based on the two approaches used in this study recalibrate the ages of the major platyrrhine clades and corroborate the hypothesis that they constitute very old lineages. These results can help reconcile several controversial points concerning the affinities of key early Miocene fossils that have arisen among paleontologists and molecular systematists. However, they cannot resolve the controversy of whether these fossil species truly belong to the extant lineages or to a stem platyrrhine clade. That question can only be resolved by morphology. Finally, we show that the use of different approaches and well supported fossil information gives a more robust divergence time estimate of a clade.

Phylogenetic evidence suggests that platyrrhine (or New World) monkeys and caviomorph rodents of the Western Hemisphere derive from source groups from the Eocene of Afro-Arabia, a landmass that was ~1500 to 2000 kilometers east of South America during the late Paleogene. Here, we report evidence for a third mammalian lineage of African origin in the Paleogene of South America—a newly discovered genus and species of parapithecid anthropoid primate from Santa Rosa in Amazonian Perú. Bayesian clock–based phylogenetic analysis nests this genus (Ucayalipithecus) deep within the otherwise Afro-Arabian clade Parapithecoidea and indicates that transatlantic rafting of the lineage leading to Ucayalipithecus likely took place between ~35 and ~32 million years ago, a dispersal window that includes the major worldwide drop in sea level that occurred near the Eocene-Oligocene boundary.