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The Tree of Life will be irrevocably reshaped as anthropogenic extinctions continue to unfold. Theory suggests that lineage evolutionary dynamics, such as age since origination, historical extinction filters and speciation rates, have influenced ancient extinction patterns – but whether these factors also contribute to modern extinction risk is largely unknown. We examine evolutionary legacies in contemporary extinction risk for over 4000 genera, representing ~30,000 species, from the major tetrapod groups: amphibians, birds, turtles and crocodiles, squamate reptiles and mammals. We find consistent support for the hypothesis that extinction risk is elevated in lineages with higher recent speciation rates. We subsequently test, and find modest support for, a primary mechanism driving this pattern: that rapidly diversifying clades predominantly comprise range-restricted, and extinction-prone, species. These evolutionary patterns in current imperilment may have important consequences for how we manage the erosion of biological diversity across the Tree of Life.

Pneumocystis jirovecii, the fungal agent of human Pneumocystis pneumonia, is closely related to macaque Pneumocystis. Little is known about other Pneumocystis species in distantly related mammals, none of which are capable of establishing infection in humans. The molecular basis of host specificity in Pneumocystis remains unknown as experiments are limited due to an inability to culture any species in vitro. To explore Pneumocystis evolutionary adaptations, we have sequenced the genomes of species infecting macaques, rabbits, dogs and rats and compared them to available genomes of species infecting humans, mice and rats. Complete whole genome sequence data enables analysis and robust phylogeny, identification of important genetic features of the host adaptation, and estimation of speciation timing relative to the rise of their mammalian hosts. Our data reveals insights into the evolution of P. jirovecii, the sole member of the genus able to infect humans., Cissé, Ma et al. utilize genomic data from Pneumocystis species infecting macaques, rabbit, dogs and rats to investigate the molecular basis of host specificity in Pneumocystis. Their analyses provide insight to the specific adaptations enabling the infection of humans by P. jirovecii.

Domestic and captive animals and cultivated plants should be recognised as integral components in contemporary ecosystems. They interact with wild organisms through such mechanisms as hybridization, predation, herbivory, competition and disease transmission and, in many cases, define ecosystem properties. Nevertheless, it is widespread practice for data on domestic, captive and cultivated organisms to be excluded from biodiversity repositories, such as natural history collections. Furthermore, there is a lack of integration of data collected about biodiversity in disciplines, such as agriculture, veterinary science, epidemiology and invasion science. Discipline-specific data are often intentionally excluded from integrative databases in order to maintain the “purity” of data on natural processes. Rather than being beneficial, we argue that this practise of data exclusivity greatly limits the utility of discipline-specific data for applications ranging from agricultural pest management to invasion biology, infectious disease prevention and community ecology. This problem can be resolved by data providers using standards to indicate whether the observed organism is of wild or domestic origin and by integrating their data with other biodiversity data (e.g. in the Global Biodiversity Information Facility). Doing so will enable efforts to integrate the full panorama of biodiversity knowledge across related disciplines to tackle pressing societal questions.

Preventing extinctions requires understanding macroecological patterns of vulnerability or persistence. However, correlates of risk can be nonlinear, within-species risk varies geographically, and current-day threats cannot reveal drivers of past losses. We investigated factors that regulated survival or extinction in Caribbean mammals, which have experienced the globally highest level of human-caused postglacial mammalian extinctions, and included all extinct and extant Holocene island populations of non-volant species (219 survivals or extinctions across 118 islands). Extinction selectivity shows a statistically detectable and complex body mass effect, with survival probability decreasing for both mass extremes, indicating that intermediate-sized species have been more resilient. A strong interaction between mass and age of first human arrival provides quantitative evidence of larger mammals going extinct on the earliest islands colonized, revealing an extinction filter caused by past human activities. Survival probability increases on islands with lower mean elevation (mostly small cays acting as offshore refugia) and decreases with more frequent hurricanes, highlighting the risk of extreme weather events and rising sea levels to surviving species on low-lying cays. These findings demonstrate the interplay between intrinsic biology, regional ecology and specific local threats, providing insights for understanding drivers of biodiversity loss across island systems and fragmented habitats worldwide.

Summary Reconstructing the tempo at which biodiversity arose is a fundamental goal of evolutionary biologists, yet the relative merits of evolutionary-rate estimates are debated based on whether they are derived from the fossil record or time-calibrated phylogenies (timetrees) of living species. Extinct lineages unsampled in timetrees are known to "pull" speciation rates downward, but the temporal scale at which this bias matters is unclear. To investigate this problem, we compare mammalian diversification-rate signatures in a credible set of molecular timetrees (n = 5,911 species, ∼70% from DNA) to those in fossil genus durations (n = 5,320). We use fossil extinction rates to correct or "push" the timetree-based (pulled) speciation-rate estimates, finding a surge of speciation during the Paleocene (∼66–56 million years ago, Ma) between the Cretaceous-Paleogene (K-Pg) boundary and the Paleocene-Eocene Thermal Maximum (PETM). However, about two-thirds of the K-Pg-to-PETM originating taxa did not leave modern descendants, indicating that this rate signature is likely undetectable from extant lineages alone. For groups without substantial fossil records, thankfully all is not lost. Pushed and pulled speciation rates converge starting ∼10 Ma and are equal at the present day when recent evolutionary processes can be estimated without bias using species-specific "tip" rates of speciation. Clade-wide moments of tip rates also enable enriched inference, as the skewness of tip rates is shown to approximate a clade's extent of past diversification-rate shifts. Molecular timetrees need fossil-correction to address deep-time questions, but they are sufficient for shallower time questions where extinctions are fewer.

The insular radiation of hutias is remarkable among mammals for its high rate of extinction during the Holocene (∼58% of species), yet fragments of intact habitat throughout the West Indies retain a critical portion of endemic diversity needing assessment. Cuba contains 8 of the 11 recognized living species of hutias, with surviving forms also on Hispaniola, Jamaica, and the Bahamas. Herein, we performed molecular phylogenetic analyses across populations of Cuban hutias in the genera Capromys, Mesocapromys, and Mysateles to address major gaps in our understanding of their species limits, phylogenetic structure, and geographic distributions. Comparing sequences of mitochondrial genes (cyt-b, COI, 12S rRNA) from 41 individuals and 21 sites across the archipelago, we found evidence that Capromys pilorides contains a major species-level subdivision from western to eastern Cuba, spanning a greater geographic region than previously hypothesized. Populations of Capromys in each clade last shared a common ancestor ∼1.1 million years ago (Ma; 5.2% cyt-b divergence). The western clade is further subdivided between mainland hutias (C. p. pilorides) and those on Isla de la Juventud plus Cayo Cantiles (C. p. relictus has priority). The eastern clade contains all Capromys east of Sierra del Escambray in central Cuba, including mainland and insular forms. However, without paired analyses of morphology and genetics or data from type localities, we cannot assign a name to the eastern Capromys sp. nov. at this time. Divergencetime analyses across 9 named species of hutias (plus 1 extinct), including nuclear genes (GHR, vWF, RAG1), dates the Capromyidae split from their South American relatives (Echimyidae) at 15.5 Ma. The crown radiation of hutias was 8.8 Ma, with successive divergences at 5.4 Ma (Geocapromys), 3.1 Ma (Capromys), and 2.2 Ma (Mysateles–Mesocapromys). Detailed surveys are needed to assess the conservation status of these evolutionarily distinct Cuban taxa.

The majority (90%) of native terrestrial mammal species living in the Dominican Republic are bats, and two-thirds of these species are endemic to the Caribbean. However, recent molecular studies using DNA barcoding of the mitochondrial cytochrome c oxidase subunit 1 gene have suggested at least a 25% underestimation of biodiversity in bats throughout the world. A recent survey of bats in the Dominican Republic documented 15 of the 18 known species on the island of Hispaniola. Phylogenetic analysis of 132 individuals resulted in well-supported monophyletic species-level clades (maximal bootstrap values) with intraspecific variation ranging from 0% to 4.7% and interspecific variation ranging from 14.1% to 32.5%. A phylogeographic pattern separating the northern and southern Dominican Republic was recovered in 3 species of bats (Macrotus waterhousii, Pteronotus parnellii, and Pteronotus quadridens). The inclusion of broader geographic sampling across the Neotropics indicated that 3 widely distributed species (Eptesicus fuscus, Molossus molossus, and Monophyllus redmani) have high sequence divergence among insular or between insular and continental populations. Further systematic study is needed to identify morphologically cryptic species and their implications for conservation priorities in the Caribbean.

“What is crucial for your ability to communicate with me… pivots on the recipient’s capacity to interpret—to make good inferential sense of the meanings that the declarer is able to send” (Rescher 2000, p148). Conventional approaches to reconciling taxonomic information in biodiversity databases have been based on string matching for unique taxonomic name combinations (Kindt 2020, Norman et al. 2020). However, in their original context, these names pertain to specific usages or taxonomic concepts, which can subsequently vary for the same name as applied by different authors. Name-based synonym matching is a helpful first step (Guala 2016, Correia et al. 2018), but may still leave considerable ambiguity regarding proper usage (Fig. 1). Therefore, developing "taxonomic intelligence" is the bioinformatic challenge to adequately represent, and subsequently propagate, this complex name/usage interaction across trusted biodiversity data networks. How do we ensure that senders and recipients of biodiversity data not only can share messages but do so with “good inferential sense” of their respective meanings? Key obstacles have involved dealing with the complexity of taxonomic name/usage modifications through time, both in terms of accounting for and digitally representing the long histories of taxonomic change in most lineages. An important critique of proposals to use name-to-usage relationships for data aggregation has been the difficulty of scaling them up to reach comprehensive coverage, in contrast to name-based global taxonomic hierarchies (Bisby 2011). The Linnaean system of nomenclature has some unfortunate design limitations in this regard, in that taxonomic names are not unique identifiers, their meanings may change over time, and the names as a string of characters do not encode their proper usage, i.e., the name “Genus species” does not specify a source defining how to use the name correctly (Remsen 2016, Sterner and Franz 2017). In practice, many people provide taxonomic names in their datasets or publications but not a source specifying a usage. The information needed to map the relationships between names and usages in taxonomic monographs or revisions is typically not presented it in a machine-readable format. New approaches are making progress on these obstacles. Theoretical advances in the representation of taxonomic intelligence have made it increasingly possible to implement efficient querying and reasoning methods on name-usage relationships (Chen et al. 2014, Chawuthai et al. 2016, Franz et al. 2015). Perhaps most importantly, growing efforts to produce name-usage mappings on a medium scale by data providers and taxonomic authorities suggest an all-or-nothing approach is not required. Multiple high-profile biodiversity databases have implemented internal tools for explicitly tracking conflicting or dynamic taxonomic classifications, including eBird using concept relationships from AviBase (Lepage et al. 2014); NatureServe in its Biotics database; iNaturalist using its taxon framework (Loarie 2020); and the UNITE database for fungi (Nilsson et al. 2019). Other ongoing projects incorporating taxonomic intelligence include the Flora of Alaska (Flora of Alaska 2020), the Mammal Diversity Database (Mammal Diversity Database 2020) and PollardBase for butterfly population monitoring (Campbell et al. 2020).

Big, time-scaled phylogenies are fundamental to connecting evolutionary processes to modern biodiversity patterns. Yet inferring reliable phylogenetic trees for thousands of species involves numerous trade-offs that have limited their utility to comparative biologists. To establish a robust evolutionary timescale for all approximately 6,000 living species of mammals, we developed credible sets of trees that capture root-to-tip uncertainty in topology and divergence times. Our “backbone-and-patch” approach to tree building applies a newly assembled 31-gene supermatrix to two levels of Bayesian inference: (1) backbone relationships and ages among major lineages, using fossil node or tip dating, and (2) species-level “patch” phylogenies with nonoverlapping in-groups that each correspond to one representative lineage in the backbone. Species unsampled for DNA are either excluded (“DNA-only” trees) or imputed within taxonomic constraints using branch lengths drawn from local birth–death models (“completed” trees). Joining time-scaled patches to backbones results in species-level trees of extant Mammalia with all branches estimated under the same modeling framework, thereby facilitating rate comparisons among lineages as disparate as marsupials and placentals. We compare our phylogenetic trees to previous estimates of mammal-wide phylogeny and divergence times, finding that (1) node ages are broadly concordant among studies, and (2) recent (tip-level) rates of speciation are estimated more accurately in our study than in previous “supertree” approaches, in which unresolved nodes led to branch-length artifacts. Credible sets of mammalian phylogenetic history are now available for download at http://vertlife.org/phylosubsets, enabling investigations of long-standing questions in comparative biology., This study presents a newly robust evolutionary timescale for ~6000 extant species of mammals, aimed at understanding their species-specific rates of diversification and distinct phylogenetic history. Ages and relationships in the tree of life are estimated with probabilistic confidence levels to help future tests of eco-evolutionary hypotheses.

Biodiversity is distributed unevenly from the poles to the equator, and among branches of the tree of life, yet how those enigmatic patterns are related is unclear. We investigated global speciation-rate variation across crown Mammalia using a novel time-scaled phylogeny (N=5,911 species, ~70% with DNA), finding that trait- and latitude-associated speciation has caused uneven species richness among groups. We identify 24 branch-specific shifts in net diversification rates linked to ecological traits. Using time-slices to define clades, we show that speciation rates are a stronger predictor of clade richness than age. Speciation is slower in tropical than extra-tropical lineages, but only at the level of clades not species tips, consistent with fossil evidence that the latitudinal diversity gradient may be a relatively young phenomenon in mammals. In contrast, species tip rates are fastest in mammals that are low dispersal or diurnal, consistent with models of ephemeral speciation and ecological opportunity, respectively. These findings juxtapose nested levels of diversification, suggesting a central role of species turnover gradients in generating uneven patterns of modern biodiversity.

The genome of the red vizcacha rat (Rodentia, Octodontidae, Tympanoctomys barrerae) is the largest of all mammals, and about double the size of their close relative, the mountain vizcacha rat Octomys mimax, even though the lineages that gave rise to these species diverged from each other only about five million years ago. The mechanism for this rapid genome expansion is controversial, and hypothesized to be a consequence of whole genome duplication or accumulation of repetitive elements. To test these alternative but nonexclusive hypotheses, we gathered and evaluated evidence from whole transcriptome and whole genome sequences of T. barrerae and O. mimax. We recovered support for genome expansion due to accumulation of a diverse assemblage of repetitive elements, which represent about one half and one fifth of the genomes of T. barrarae and O. mimax, respectively, but we found no strong signal of whole genome duplication. In both species, repetitive sequences were rare in transcribed regions as compared to the rest of the genome, and mostly had no close match to annotated repetitive sequences from other rodents. These findings raise new questions about the genomic dynamics of these repetitive elements, their connection to widespread chromosomal fissions that occurred in the T. barrerae ancestor, and their fitness effects ? including during the evolution of hypersaline dietary tolerance in T. barrerae. Fil: Evans, Ben J.. Mc Master University; Canadá Fil: Upham, Nathan S.. Mc Master University; Canadá. Field Museum of Natural History; Estados Unidos. University of Yale; Estados Unidos Fil: Golding, G. Brian. Mc Master University; Canadá Fil: Ojeda, Ricardo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; Argentina Fil: Ojeda, Agustina Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; Argentina

International audience; Echimyidae is one of the most speciose and ecologically diverse rodent families in the world, occupying a wide range of habitats in the Neotropics. However, a resolved phylogeny at the genus-level is still lacking for these 22 genera of South American spiny rats, including the coypu (Myocastorinae), and 5 genera of West Indian hutias (Capromyidae) relatives. Here, we used Illumina shotgun sequencing to assemble 38 new complete mitogenomes, establishing Echimyidae, and Capromyidae as the first major rodent families to be completely sequenced at the genus-level for their mitochondrial DNA. Combining mitogenomes and nuclear exons, we inferred a robust phylogenetic framework that reveals several newly supported nodes as well as the tempo of the higher level diversification of these rodents. Incorporating the full generic diversity of extant echimyids leads us to propose a new higher level classification of two subfamilies: Euryzygomatomyinae and Echimyinae. Of note, the enigmatic Carterodon displays fast-evolving mitochondrial and nuclear sequences, with a long branch that destabilizes the deepest divergences of the echimyid tree, thereby challenging the sister-group relationship between Capromyidae and Euryzygomatomyinae. Biogeographical analyses involving higher level taxa show that several vicariant and dispersal events impacted the evolutionary history of echimyids. The diversification history of Echimyidae seems to have been influenced by two major historical factors, namely (1) recurrent connections between Atlantic and Amazonian Forests and (2) the Northern uplift of the Andes.

Evolutionary radiations on continents are less well-understood and appreciated than those occurring on islands. The extent of ecological influence on species divergence can be evaluated to determine whether a radiation was ultimately the outcome of divergent natural selection or else arose mainly by nonecological divergence. Here, we used phylogenetic comparative methods to test distinct hypotheses corresponding to adaptive and nonadaptive evolutionary scenarios for the morphological evolution of sigmodontine rodents. Results showed that ecological variables (diet and life-mode) explain little of the shape and size variation of sigmodontine skulls and mandibles. A Brownian model with varying rates for insectivory versus all other diets was the most likely evolutionary model. The insectivorous sigmodontines have a faster rate of morphological evolution than mice feeding on other diets, possibly due to stronger selection for features that aid insectivory. We also demonstrate that rapid early-lineage diversification is not accompanied by high morphological divergence among subclades, contrasting with island results. The geographic size of continents permits spatial segregation to a greater extent than on islands, allowing for allopatric distributions and escape from interspecific competition. We suggest that continental radiations of rodents are likely to produce a pattern of high species diversification coupled with a low degree of phenotypic specialization.

Background The tropical Andes and Amazon are among the richest regions of endemism for mammals, and each has given rise to extensive in situ radiations. Various animal lineages have radiated ex situ after colonizing one of these regions from the other: Amazonian clades of dendrobatid frogs and passerine birds may have Andean ancestry, and transitions from the Amazon to Andes may be even more common. To examine biogeographic transitions between these regions, we investigated the evolutionary history of three clades of rodents in the family Echimyidae: bamboo rats (Dactylomys-Olallamys-Kannabateomys), spiny tree-rats (Mesomys-Lonchothrix), and brush-tailed rats (Isothrix). Each clade is distributed in both the Andes and Amazonia, and is more diverse in the lowlands. We used two mitochondrial (cyt- b and 12S) and three nuclear (GHR, vWF, and RAG1) markers to reconstruct their phylogenetic relationships. Tree topologies and ancestral geographic ranges were then used to determine whether Andean forms were basal to or derived from lowland radiations. Results Four biogeographic transitions are identified among the generic radiations. The bamboo rat clade unambiguously originated in the Amazon ca. 9 Ma, followed by either one early transition to the Andes (Olallamys) and a later move to the Amazon (Dactylomys), or two later shifts to the Andes (one in each genus). The Andean species of both Dactylomys and Isothrix are sister to their lowland species, raising the possibility that highland forms colonized the Amazon Basin. However, uncertainty in their reconstructed ancestral ranges obscures the origin of these transitions. The lone Andean species of Mesomys is confidently nested within the lowland radiation, thereby indicating an Amazon-to-Andes transition ca. 2 Ma. Conclusions Differences in the timing of these biogeographic transitions do not appear to explain the different polarities of these trees. Instead, even within the radiation of a single family, both Andean and Amazonian centers of endemism appear enriched by lineages that originated in the other region. Our survey of other South American lineages suggests a pattern of reciprocal exchange between these regions—among mammals, birds, amphibians, and insects we found no fewer than 87 transitions between the Andes and Amazon from Miocene-Pleistocene. Because no clear trend emerges between the timing and polarity of transitions, or in their relative frequency, we suggest that reciprocal exchange between tropical highland and lowland faunas in South America has been a continual process since ca. 12 Ma.