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Aim Our aim was to examine gracile capuchin (Cebus) and robust capuchin monkey (Sapajus) diversification, with a focus on recent Sapajus expansion within Amazonia. We wanted to reconstruct the biogeographical history of the clade using statistical methods that model lineages' occupation of different regions over time in order to evaluate recently proposed 'Out of Amazonia' and 'Reinvasion of Amazonia' hypotheses as alternative explanations for the extensive geographical overlap between reciprocally monophyletic gracile (Cebus) and robust (Sapajus) capuchin monkeys.Location Central and South America.Methods We reconstructed a time-calibrated molecular phylogeny for capuchins under Bayesian inference from three mitochondrial genes. We then categorized 12 capuchin clades across four Neotropical centres of endemism and reconstructed the biogeographical history of the capuchin radiation using six models implemented in 'BioGeoBEARS'. We performed a phylogeographical analysis for a robust capuchin clade that spans the Atlantic Forest, Cerrado, Caatinga and Amazonia. ResultsWe find support for a late Miocene vicariant Cebus-Sapajus divergence and a Pleistocene Sapajus invasion of Amazonia from the Atlantic Forest. Our new analyses confirm Sapajus diversified first in the Atlantic Forest, with subsequent range expansion into widespread sympatry with Cebus in Amazonia, as well as multiple expansions into drier savanna-like habitats. We do not find mitochondrial molecular congruence with morphological species distinctions for Sapajus flavius, S. cay, S. macrocephalus, S. libidinosus and S. apella; instead, these five morphological types together form a single widespread clade (Bayesian posterior probability = 1) with geographical substructure and shared ancestry during the Pleistocene.Main conclusions Our results support vicariance dividing ancestral capuchin populations in Amazonia versus the Atlantic Forest, and a Pleistocene 'Amazonian invasion' by Sapajus to explain the present-day sympatry of Cebus and Sapajus.

Twelve generic names have been ascribed to the New World tamarins but all are currently placed in just one: Saguinus Hoffmannsegg, 1807. Based on geographical distributions, morphology, and pelage patterns and coloration, they have been divided into six species groups: (1) nigricollis, (2) mystax, (3) midas, (4) inustus, (5) bicolor and (6) oedipus. Molecular phylogenetic studies have validated five of these groups; each are distinct clades. Saguinus inustus is embedded in the mystax group. Genetic studies show that tamarins are sister to all other callitrichids, diverging 15À13 Ma. The small-bodied nigricollis group diverged from the remaining, larger tamarins 11À8 Ma, and the mystax group diverged 7À6 Ma; these radiations are older than those of the marmosets (Callithrix, Cebuella, Mico), which began to diversify 6À5 Ma. The oedipus group diverged from the midas and bicolor groups 5À4 Ma. We review recent taxonomic changes and summarize the history of the generic names. Taking into account the Late Miocene divergence time (11À8 Ma) between the large-and smallbodied tamarin lineages, the small size of the nigricollis group species when compared with other tamarins, and the sympatry of the nigricollis group species with the larger mystax group species, we argue that the nigricollis group be recognized as a distinct genus: Leontocebus Wagner, 1839.

Phylogenetic relationships amongst the robust capuchin monkeys (genus Sapajus) are poorly understood. Morphology-based taxonomies have recognized anywhere from one to twelve different species. The current IUCN (2017) classification lists eight robust capuchins: S. xanthosternos, S. nigritus, S. robustus, S. flavius, S. libidinosus, S. cay, S. apella and S. macrocephalus. Here, we assembled the first phylogenomic data set for Sapajus using ultra-conserved elements (UCEs) to reconstruct a capuchin phylogeny. All phylogenomic analyses strongly supported a deep divergence of Sapajus and Cebus clades within the capuchin monkeys, and provided support for Sapajus nigritus, S. robustus and S. xanthosternos as distinct species. However, the UCE phylogeny lumped the putative species S. cay, S. libidinosus, S. apella, S. macrocephalus, and S. flavius together as a single widespread lineage. A SNP phylogeny constructed from the UCE data was better resolved and recovered S. flavius and S. libidinosus as sister species; however, S. apella, S. macrocephalus, and S. cay individuals were recovered in two geographic clades, from northeastern and southwestern Amazon, rather than clustering by currently defined morphospecies. STRUCTURE analysis of population clustering revealed widespread admixture among Sapajus populations within the Amazon and even into the Cerrado and Atlantic Forest. Difficulty in assigning species by morphology may be a result of widespread population admixture facilitated through frequent movement across major rivers and even ecosystems by robust capuchin monkeys.

A voucher is a permanently preserved specimen that is maintained in an accessible collection. In genomics, vouchers serve as the physical evidence for the taxonomic identification of genome assemblies. Unfortunately, the vast majority of vertebrate genomes stored in the Genbank database do not refer to voucher specimens. Here, we urge researchers generating new genome assemblies to deposit voucher specimens in accessible, permanent research collections, and to link these vouchers to publications, public databases, and repositories. We also encourage scientists to deposit voucher specimens in order to recognize the work of local field biologists and promote a diverse and inclusive knowledge base, and we recommend best practices to in voucher deposition to prevent taxonomic errors and ensure reproducibility and legality in genetic studies.

Spiny-rayed fishes (Acanthomorpha) dominate modern marine habitats and comprise more than a quarter of all living vertebrate species 1-3 . It is believed that this dominance resulted from explosive lineage and phenotypic diversification coincident with the Cretaceous-Paleogene (K-Pg) mass-extinction event 4 . It remains unclear, however, if living acanthomorph diversity is the result of a punctuated burst or gradual accumulation of diversity following the K-Pg. We assess these hypotheses with a time-calibrated phylogeny inferred using ultraconserved elements from a sampling of species that represent over 91% of all acanthomorph families, as well as an extensive body shape dataset of extant species. Our results indicate that several million years after the end-Cretaceous, acanthomorphs underwent a prolonged and significant expansion of morphological disparity primarily driven by changes in body elongation, and that acanthomorph lineages containing the bulk of the living species diversity originated throughout the Cenozoic. These acanthomorph lineages radiated into distinct regions of morphospace and retained their iconic phenotypes, including a large group of laterally compressed reef fishes, fast-swimming open-ocean predators, bottom-dwelling flatfishes, seahorses, and pufferfishes. The evolutionary success of spiny-rayed fishes is the culmination of a post K-Pg adaptive radiation in which rates of lineage diversification were decoupled from periods of high phenotypic disparity. MainThe Cretaceous-Paleogene (K-Pg) mass extinction fundamentally affected the evolutionary trajectory of terrestrial vertebrates, laying the foundation for spectacular radiations Main references1 Near, T. J. et al. Phylogeny and tempo of diversification in the superradiation of spinyrayed fishes.

Spiny-rayed fishes (Acanthomorpha) dominate modern marine habitats and comprise more than a quarter of all living vertebrate species1-3. It is believed that this dominance resulted from explosive lineage and phenotypic diversification coincident with the Cretaceous-Paleogene (K-Pg) mass-extinction event4. It remains unclear, however, if living acanthomorph diversity is the result of a punctuated burst or gradual accumulation of diversity following the K-Pg. We assess these hypotheses with a time-calibrated phylogeny inferred using ultraconserved elements from a sampling of species that represent over 91% of all acanthomorph families, as well as an extensive body shape dataset of extant species. Our results indicate that several million years after the end-Cretaceous, acanthomorphs underwent a prolonged and significant expansion of morphological disparity primarily driven by changes in body elongation, and that acanthomorph lineages containing the bulk of the living species diversity originated throughout the Cenozoic. These acanthomorph lineages radiated into distinct regions of morphospace and retained their iconic phenotypes, including a large group of laterally compressed reef fishes, fast-swimming open-ocean predators, bottom-dwelling flatfishes, seahorses, and pufferfishes. The evolutionary success of spiny-rayed fishes is the culmination of a post K-Pg adaptive radiation in which rates of lineage diversification were decoupled from periods of high phenotypic disparity.

Chendytes lawi, an extinct flightless diving anseriform from coastal California, was traditionally classified as a sea duck, tribe Mergini, based on similarities in osteological characters. We recover and analyze mitochondrial genomes of C. lawi and five additional Mergini species, including the extinct Labrador Duck, Camptorhynchus labradorius. Despite its diving morphology, C. lawi is reconstructed as an ancient relictual lineage basal to the dabbling ducks (tribe Anatini), revealing an additional example of convergent evolution of characters related to feeding behavior among ducks. The Labrador Duck is sister to Steller's Eider which may provide insights into the evolution and ecology of this poorly known extinct species. Our results demonstrate that inclusion of full length mitogenomes, from taxonomically distributed ancient and modern sources can improve phylogeny reconstruction of groups previously assessed with shorter single-gene mitochondrial sequences.