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Biodiversity is declining worldwide. Because species interact with one another and with their environment, losses of particular organisms alter the function of ecosystems. Our understanding of the global rates and specific causes of functional decline remains limited, however. Species losses also reduce the cumulative amount of extant evolutionary history ("phylogenetic diversity" [PD]) in communities-our biodiversity heritage. Here we provide a global assessment of how each known anthropogenic threat is driving declines in functional diversity (FD) and PD, using terrestrial mammals as a case study. We find that habitat loss and harvest (e.g., legal hunting, poaching, snaring) are by far the biggest drivers of ongoing FD and PD loss. Declines in FD in high-biodiversity countries, particularly in Southeast Asia and South America, are greater than would be expected if species losses were random with respect to ecological function. Among functional guilds, herbivores are disproportionately likely to be declining from harvest, with important implications for plant communities and nutrient cycling. Frugivores are particularly likely to be declining from both harvest and habitat loss, with potential ramifications for seed dispersal and even forest carbon storage. Globally, phylogenetically unique species do not have an elevated risk of decline, but in areas such as Australia and parts of Southeast Asia, both habitat loss and harvest are biased toward phylogenetically unique species. Enhanced conservation efforts, including a renewed focus on harvest sustainability, are urgently needed to prevent the deterioration of ecosystem function, especially in the South American and equatorial Asian tropics., Competing Interests: The authors declare no competing interest.

Dicynodont therapsids were a major component of the Permo-Triassic terrestrial ecosystems across Pangea and have been regarded as specialized herbivores. In South America, the group was represented by several taxa of the clade Kannemeyeriiformes spanning from the Middle to the Late Triassic. In order to evaluate if cranial differences among taxa are potentially related to differences in feeding function, we performed a geometric morphometric analysis on 28 South American dicynodont crania. We digitized 19 cranial landmarks and conducted generalized Procrustes analysis, principal component analysis (PCA), principal component analysis between groups (bg-PCA), and a branch weighted squared-change parsimony approach. Phylogenetic inertia was not a significant driver of cranial shape evolution in the group, whereas PCA and bg-PCA support that major morphological shape differences are concentrated in the preorbital region (relative length of the snout and width of the caniniform process), in the position of quadrate condyle in relation to the caniniform process, and in the increase in the intertemporal surface area. In this context, tusked Dinodontosaurus, "Kannemeyeria," and Vinceria have relatively smaller adductor attachment areas and input moment arm than younger taxa lacking tusks, such as Ischigualastia, Stahleckeria, and Jachaleria. Differences in cranial morphology in later dicynodonts reflect modifications in feeding mechanics, probably due to changes in food resources (vegetation) in their habitats toward the end of the Triassic., (© 2019 Wiley Periodicals, Inc.)

We sequenced the mitochondrial DNA (mtDNA) control region of 59 peccaries (44 white-lipped peccaries, Tayassu pecari, and 15 collared peccaries, Pecari tajacu). We also genotyped 3 DNA microsatellites from 78 white-lipped peccaries representing the 4 putative morphological subspecies (i.e., spiradens, aequatoris, pecari, and albirostris) present in northwestern South America (i.e., Colombia, Ecuador, Peru, and Bolivia). Our results showed: 1) the estimated diversity of the mtDNA control region in the T. pecari population was extremely high, whereas the average genetic diversity for the microsatellites was medium to high and similar to that observed in European pig breeds; 2) there was no significant genetic heterogeneity among the quoted putative morphological subspecies at the mitochondrial marker, but we did detect significant (although relatively small) genetic heterogeneity using microsatellites, indicating that T. pecari albirostris is a uniquely differentiated group; and 3) the phylogenetic mtDNA trees showed that haplotypes were intermixed independent of their "a priori" subspecies classification. In addition, the microsatellite assignation analyses yielded low percentages of well-classified individuals when the analysis considered the geographic morphology of the subspecies. Thus, the molecular results do not support the putative morphological subspecies of T. pecari in northwestern South America. Finally, our results did not detect clear historical demographic changes using the mtDNA control region sequences. These genetic results are discussed in the context of the ecological and social characteristics of T. pecari.

Since the late eighteenth century, fossils of bizarre extinct creatures have been described from the Americas, revealing a previously unimagined chapter in the history of mammals. The most bizarre of these are the 'native' South American ungulates thought to represent a group of mammals that evolved in relative isolation on South America, but with an uncertain affinity to any particular placental lineage. Many authors have considered them descended from Laurasian 'condylarths', which also includes the probable ancestors of perissodactyls and artiodactyls, whereas others have placed them either closer to the uniquely South American xenarthrans (anteaters, armadillos and sloths) or the basal afrotherians (e.g. elephants and hyraxes). These hypotheses have been debated owing to conflicting morphological characteristics and the hitherto inability to retrieve molecular information. Of the 'native' South American mammals, only the toxodonts and litopterns persisted until the Late Pleistocene-Early Holocene. Owing to known difficulties in retrieving ancient DNA (aDNA) from specimens from warm climates, this research presents a molecular phylogeny for both Macrauchenia patachonica (Litopterna) and Toxodon platensis (Notoungulata) recovered using proteomics-based (liquid chromatography-tandem mass spectrometry) sequencing analyses of bone collagen. The results place both taxa in a clade that is monophyletic with the perissodactyls, which today are represented by horses, rhinoceroses and tapirs.

Untangling the root of the evolutionary tree of placental mammals has been nearly an impossible task. The good news is that only three possibilities are seriously considered. The bad news is that all three possibilities are seriously considered. Paleontologists favor a root anchored by Xenarthra (e.g., sloths and anteater), whereas molecular evolutionists have favored the two other possible roots: Afrotheria (e.g., elephants, hyraxes, and tenrecs) and Atlantogenata (Afrotheria + Xenarthra). Now, two groups of researchers have scrutinized the largest available genomic data sets bearing on the question and have come to opposite conclusions, as reported in this issue of Molecular Biology and Evolution. Needless to say, more research is needed.

Background: This paper tests Vrba's resource-use hypothesis, which predicts that generalist species have lower specialization and extinction rates than specialists, using the 879 species of South American mammals. We tested several predictions about this hypothesis using the biomic specialization index (BSI) for each species, which is based on its geographical range within different climate-zones. The four predictions tested are: (1) there is a high frequency of species restricted to a single biome, which henceforth are referred to as stenobiomic species, (2) certain clades are more stenobiomic than others, (3) there is a higher proportion of biomic specialists in biomes that underwent through major expansion-contraction alternation due to the glacial-interglacial cycles, (4) certain combinations of inhabited biomes occur more frequently among species than do others., Results: Our results are consistent with these predictions. (1) We found that 42 % of the species inhabit only one biome. (2) There are more generalists among species of Carnivora than in clades of herbivores. However, Artiodactyla, shows a distribution along the specialization gradient different from the one expected. (3) Biomic specialists are predominant in tropical rainforest and desert biomes. Nevertheless, we found some differences between small and large mammals in relation to these results. Stenobiomic species of micromammalian clades are more abundant in most biomes than expected by chance, while in the case of macromammalian clades stenobiomic species are more frequent than expected in tropical rainforest, tropical deciduous woodland and desert biomes only. (4) The most frequent combinations of inhabited biomes among the South American mammals are those with few biomes, i.e., the ones that suffered a higher rate of vicariance due to climatic cycles., Conclusion: Our results agree with the resource-use hypothesis and, therefore, with a major role of the past climatic changes as drivers of mammalian evolution. Nevertheless, deviations from the expectations indicate the importance of differences in reproductive traits and paleobiogeographic history for the macroevolutionary processes involved. In the case of South American mammals, the Pliocene Great American Biotic Interchange strongly influences the ecological characteristics of this assemblage. Furthermore, the Andes have acted as a fertile ground for speciation in environments prone to vicariance. Finally, the micromammals appear as more prone to biomic specialization than larger species. These factors are responsible for some of the differences found between South America and Africa in the studied pattern. For example, the extensive South American mountain ranges favour a higher number of combinations of inhabited biomes in comparison with Africa.

Life on Earth is characterized by strong diversity skewness: related lineages typically show pronounced variation in diversification success, and clades contain hyperdiverse and depauperate subclades. Previous studies have documented diversity skewness only for entire (global) clades. We demonstrate methods for measurement and significance testing of diversity skewness of local assemblages and regional biotas; we illustrate this with an analysis of geographic structure in diversity skewness of primate assemblages. For primates, continental faunas differ in diversity skewness from expectations based on the global phylogeny: South American faunas have significantly low skewness and African faunas have significantly high skewness. However, no local assemblage has diversity skewness different from that expected based on sampling the continental fauna. We also document a latitudinal gradient in diversity skewness for the African assemblages and test for (but do not find) associations of skewness with longitude, local species richness, and net primary productivity. Our data suggest that continental-scale biogeographic events rather than local-scale processes have shaped diversity skewness in modern primate faunas.

Molecular phylogenetic studies have resolved placental mammals into four major groups, but have not established the full hierarchy of interordinal relationships, including the position of the root. The latter is critical for understanding the early biogeographic history of placentals. We investigated placental phylogeny using Bayesian and maximum-likelihood methods and a 16.4-kilobase molecular data set. Interordinal relationships are almost entirely resolved. The basal split is between Afrotheria and other placentals, at about 103 million years, and may be accounted for by the separation of South America and Africa in the Cretaceous. Crown-group Eutheria may have their most recent common ancestry in the Southern Hemisphere (Gondwana).