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Author(s): Indr liobait (corresponding author) [1, 2, 3]; Mikael Fortelius [1, 2]; Nils C. Stenseth [2] In the fossil record, taxa exhibit a regular pattern of waxing and waning of [...]

Localized ecological systems are known to shift abruptly and irreversibly from one state to another when they are forced across critical thresholds. Here we review evidence that the global ecosystem as a whole can react in the same way and is approaching a planetary-scale critical transition as a result of human influence. The plausibility of a planetary-scale 'tipping point' highlights the need to improve biological forecasting by detecting early warning signs of critical transitions on global as well as local scales, and by detecting feedbacks that promote such transitions. It is also necessary to address root causes of how humans are forcing biological changes., Humans now dominate Earth, changing it in ways that threaten its ability to sustain us and other species (1-3). This realization has led to a growing interest in forecasting biological [...]

The Cretaceous-Paleogene mass extinction approximately 66 million years ago is conventionally thought to have been a turning point in mammalian evolution (1,2). Prior to that event and for the first two-thirds of their evolutionary history, mammals were mostly confined to roles as generalized, small-bodied, nocturnal insectivores (3), presumably under selection pressures from dinosaurs (4). Release from these pressures, by extinction of non-avian dinosaurs at the Cretaceous-Paleogene boundary, triggered ecological diversification of mammals (1,2). Although recent individual fossil discoveries have shown that some mammalian lineages diversified ecologically during the Mesozoic era (5), comprehensive ecological analyses of mammalian groups crossing the Cretaceous-Paleogene boundary are lacking. Such analyses are needed because diversification analyses of living taxa (6,7) allow only indirect inferences of past ecosystems. Here we show that in arguably the most evolutionarily successful clade of Mesozoic mammals, the Multituberculata, an adaptive radiation began at least 20 million years before the extinction of non-avian dinosaurs and continued across the Cretaceous-Paleogene boundary. Disparity in dental complexity, which relates to the range of diets, rose sharply in step with generic richness and disparity in body size. Moreover, maximum dental complexity and body size demonstrate an adaptive shift towards increased herbivory. This dietary expansion tracked the ecological rise of angiosperms (8) and suggests that the resources that were available to multituberculates were relatively unaffected by the Cretaceous-Paleogene mass extinction. Taken together, our results indicate that mammals were able to take advantage of new ecological opportunities in the Mesozoic and that at least some of these opportunities persisted through the Cretaceous-Paleogene mass extinction. Similar broad-scale ecomorphological inventories of other radiations may help to constrain the possible causes of mass extinctions (9,10)., Multituberculate mammals were a taxonomically rich (3,11) and numerically abundant (12) clade that had originated by the Middle Jurassic epoch (approximately 165 million years (Myr) ago) and went extinct in [...]

The extinction of dinosaurs at the Cretaceous/Paleogene (K/Pg) boundary was the seminal event that opened the door for the subsequent diversification of terrestrial mammals. Our compilation of maximum body size at the ordinal level by sub-epoch shows a near-exponential increase after the K/Pg. On each continent, the maximum size of mammals leveled off after 40 million years ago and thereafter remained approximately constant. There was remarkable congruence in the rate, trajectory, and upper limit across continents, orders, and trophic guilds, despite differences in geological and climatic history, turnover of lineages, and ecological variation. Our analysis suggests that although the primary driver for the evolution of giant mammals was diversification to fill ecological niches, environmental temperature and land area may have ultimately constrained the maximum size achieved. 10.1126/science.1194830

The Late Miocene development of faunas and environments in western Eurasia is well known, but the climatic and environmental processes that controlled its details are incompletely understood. Here we map the rise and fall of the classic Pikermian fossil mammal chronofauna between 12 and 4.2 Ma, using genus-level faunal similarity between localities. To directly relate land mammal community evolution to environmental change, we use the hypsodonty paleoprecipitation proxy and paleoclimate modeling. The geographic distribution of faunal similarity and paleoprecipitation in successive timeslices shows the development of the open biome that favored the evolution and spread of the open-habitat adapted large mammal lineages. In the climate model run, this corresponds to a decrease in precipitation over its core area south of the Paratethys Sea. The process began in the latest Middle Miocene and climaxed in the medial Late Miocene, about 7-8 million years ago. The geographic range of the Pikermian chronofauna contracted in the latest Miocene, a time of increasing summer drought and regional differentiation of habitats in Eastern Europe and Southwestern Asia. Its demise at the Miocene-Pliocene boundary coincides with an environmental reversal toward increased humidity and forestation, changes inevitably detrimental to openadapted, wide-ranging large mammals. fossil mammals | paleoclimate | Pikermi | similarity index

Do large mammals evolve faster than small mammals or vice versa? Because the answer to this question contributes to our understanding of how life-history affects long-term and large-scale evolutionary patterns, and how microevolutionary rates scale-up to macroevolutionary rates, it has received much attention. A satisfactory or consistent answer to this question is lacking, however. Here, we take a fresh look at this problem using a large fossil dataset of mammals from the Neogene of the Old World (NOW). Controlling for sampling biases, calculating per capita origination and extinction rates of boundary-crossers and estimating survival probabilities using capture-mark-recapture (CMR) methods, we found the recurring pattern that large mammal genera and species have higher origination and extinction rates, and therefore shorter durations. This pattern is surprising in the light of molecular studies, which show that smaller animals, with their shorter generation times and higher metabolic rates, have greater absolute rates of evolution. However, higher molecular rates do not necessarily translate to higher taxon rates because both the biotic and physical environments interact with phenotypic variation, in part fueled by mutations, to affect origination and extinction rates. To explain the observed pattern, we propose that the ability to evolve and maintain behavior such as hibernation, torpor and burrowing, collectively termed 'sleep-orhide' (SLOH) behavior, serves as a means of environmental buffering during expected and unexpected environmental change. SLOH behavior is more common in some small mammals, and, as a result, SLOH small mammals contribute to higher average survivorship and lower origination probabilities among small mammals. body size | environmental buffering | metabolism | Neogene mammals | turnover

A classic example of adaptive radiation is the diversification of Cenozoic ungulates into herbivore adaptive zones. Their taxonomic diversification has been associated with changes in molar tooth morphology. Analysis of molar crown types of the Artiodactyla, Perissodactyla, and archaic ungulates ('Condylarthra') shows that the diversity of genera and crown types was high in the Eocene. Post-Eocene molars of intermediate crown types are rare, and thus the ungulate fauna contained more taxa having fewer but more disparate crown types. Taxonomic diversity trends alone give incomplete descriptions of adaptive radiations., Mammals are today the dominant terrestrial vertebrate group using plants as food(1). Mammalian herbivory has evolved independently numerous times during the past 65 million years(2). Along with rodents, ungulates are [...]

Author(s): Jukka Jernvall (corresponding author) [1, 2]; Mikael Fortelius (corresponding author) [3] During the past 20 million years, herbivorous mammals of numerous lineages have evolved hypsodont, or high-crowned, cheek teeth. [...]

The discovery of a fossil hominoid partial skull from the Upper Miocene Sinap Formation of central Turkey shows that Ankarapithecus meteai are stem members of the great ape and human clade. Contrary to findings from the more fragmentary remains, this specimen shows facial, mandibular, and dental features which differ from any of the other extant or fossil hominoid. This nearly complete specimen has a relatively narrow interorbital region, extensive frontal and maxillary sinuses, moderate supraorbital tori, square orbits, robust mandibular corpus, and incisor heteromorphy.

Molar teeth from multiple populations of Anchitherium in three dimensions were analyzed to test if anchitheriines showed any changes interpretable as adaptation to local conditions. Collectively the data obtained suggested that even a taxon such as Anchitherium, with a long and successful history of forest adaptation, responded to regional environmental changes in an adaptive manner.

Author(s): Alistair R. Evans (corresponding author) [1]; Gregory P. Wilson [2]; Mikael Fortelius [1, 3]; Jukka Jernvall [1] The study of mammalian evolution depends greatly on understanding the evolution of [...]

Author(s): Indr[e dot] [Z caron]liobait[e dot] (corresponding author) [1]; Mikael Fortelius [1] We contend that definitions of conflicts of interest (COI) in peer review need to be reassessed to reflect [...]