Palaeontology

  • Article
    | Open Access

    Harmful algal and bacterial blooms are increasingly frequent in lakes and rivers. From the Sydney Basin, Australia, this study uses fossil, sedimentary and geochemical data to reveal bloom events following forest ecosystem collapse during the end-Permian event and that blooms have consistently followed warming-related extinction events, inhibiting the recovery of freshwater ecosystems for millennia.

    • Chris Mays
    • , Stephen McLoughlin
    •  & Vivi Vajda
  • Article
    | Open Access

    Snakes are one of the most successful groups of living vertebrates, but the timing of their diversification is unclear. Combining molecular clocks, fossils, and biogeography, Klein et al. show that snakes experienced a diversification, and underwent dispersal, around the time of the end-Cretaceous mass extinction.

    • Catherine G. Klein
    • , Davide Pisani
    •  & Nicholas R. Longrich
  • Article
    | Open Access

    The linkage between temperature change and extinction rates in the fossil record is well-known qualitatively but little explored quantitatively. Here the authors investigate the relationship of marine animal extinctions with rate and magnitude of temperature change across the last 450 million years, and identify thresholds in climate change linked to mass extinctions.

    • Haijun Song
    • , David B. Kemp
    •  & Xu Dai
  • Article
    | Open Access

    The common ancestor of all living arthropods had biramous postantennal appendages, with an endopodite and exopodite branching off the limb base. This study uses microtomographic imaging of the Cambrian arthropod Leanchoilia to reveal a previously undetected exite at the base of most appendages, suggesting a deeper origin for exites in arthropod phylogeny.

    • Yu Liu
    • , Gregory D. Edgecombe
    •  & Xianguang Hou
  • Article
    | Open Access

    Increasing body and brain size constitutes a key pattern in human evolution, but the mechanisms driving these changes remain debated. Using a large fossil dataset combined with global paleoclimatic reconstructions, the authors show that different environmental variables influenced the evolution of brain and body size in Homo.

    • Manuel Will
    • , Mario Krapp
    •  & Andrea Manica
  • Article
    | Open Access

    In addition to major innovations in their locomotor system, early birds evolved highly derived skulls. Here, Wang et al. three dimensionally reconstruct the skull of a new enantiornithine bird from the Early Cretaceous that illustrates the early avialan transitions in skull morphology and function.

    • Min Wang
    • , Thomas A. Stidham
    •  & Zhonghe Zhou
  • Article
    | Open Access

    Age-richness rate (ARR) estimates of evolutionary diversification are widely used to study factors that influence species richness among clades. Here the authors show that ARR inference is based on problematic assumptions and recommend against its use in comparison of past diversity or diversification rates across clades.

    • Daniel L. Rabosky
    •  & Roger B. J. Benson
  • Article
    | Open Access

    Terrestrial ecosystems underwent major restructuring through the early Mesozoic, culminating in dinosaur-dominated faunas. Here Singh et al. use jaw morphology to classify tetrapod herbivores into distinct feeding groups and show that their success was shaped by environmental changes and competitive constraints.

    • Suresh A. Singh
    • , Armin Elsler
    •  & Michael J. Benton
  • Article
    | Open Access

    There are a number of competing explanations for the late Pleistocene extinction of many North American megafauna species. Here, the authors apply a Bayesian regression approach that finds greater concordance between megafaunal declines and climate change than with human population growth.

    • Mathew Stewart
    • , W. Christopher Carleton
    •  & Huw S. Groucutt
  • Article
    | Open Access

    The Cambrian is known as a period of rapid animal diversification, but the development of these animals is not well characterized. Here, Steiner et al. describe a new assemblage of Cambrian eggs, embryos and early postembryonic stages from Mongolia that provides insight into ancient bilaterian development and evolution.

    • Michael Steiner
    • , Ben Yang
    •  & Philip Donoghue
  • Article
    | Open Access

    The deglaciation of Marinoan snowball Earth (~635 Myr ago) has been associated with potentially extensive CH4 emissions in relation to transient marine euxinia. Here, the authors find that active methanogenesis occurred during the termination of Marinoan snowball Earth, fueled by methyl sulfide production in sulfidic seawater.

    • Zhouqiao Zhao
    • , Bing Shen
    •  & Haoran Ma
  • Article
    | Open Access

    Fungi may have evolved up to 2.4 billion years ago, but it is unclear when they first colonized land. Here Gan and colleagues report filamentous Ediacaran microfossils from South China that may represent early terrestrial fungi.

    • Tian Gan
    • , Taiyi Luo
    •  & Shuhai Xiao
  • Article
    | Open Access

    Oldupai Gorge, Tanzania is a key site for understanding early human evolution. Here, the authors report a multiproxy dataset from the Western basin of Oldupai Gorge dating to 2 million years ago, enabling the in situ comparison of lithic assemblages, paleoenvironments and hominin behavioral adaptability.

    • Julio Mercader
    • , Pam Akuku
    •  & Michael Petraglia
  • Article
    | Open Access

    Fish production is predicted to decrease with anthropogenic global warming. Here the authors analyse fish fossil assemblages from 62–46 My old deep-sea sediments and instead find a positive correlation between fish production and ocean temperature over geological timescales, which a data-constrained model explains in terms of trophic transfer efficiency and primary production.

    • Gregory L. Britten
    •  & Elizabeth C. Sibert
  • Article
    | Open Access

    High-latitude records show large diversity losses of marine plankton, such as radiolarians, with historical climate change. Here, Trubovitz et al. present a low-latitude record spanning the last 10 million years, finding that many high-latitude radiolarians did not shift equatorward but instead went extinct.

    • Sarah Trubovitz
    • , David Lazarus
    •  & Paula J. Noble
  • Article
    | Open Access

    Modern mammals are endothermic, but it has not been clear when this type of metabolism evolved. Here, Newham et al. analyse tooth and bone structure in Early Jurassic stem-mammal fossils to estimate lifespan and blood flow rates, which inform about basal and maximum metabolic rates, respectively, and show these stem-mammals had metabolic rates closer to modern ectothermic reptiles than to endothermic mammals.

    • Elis Newham
    • , Pamela G. Gill
    •  & Ian J. Corfe
  • Article
    | Open Access

    Pleistocene population dynamics can inform the consequences of current climate change. This phylogeography of 35 complete American mastodon mitochondrial genomes suggests distinct lineages in this species repeatedly expanded northwards and then went locally extinct in response to glacial cycles.

    • Emil Karpinski
    • , Dirk Hackenberger
    •  & Hendrik N. Poinar
  • Article
    | Open Access

    Non-traditional stable isotopes, such as of calcium, have potential to expand our understanding of ancient diets. Here, Martin et al. use stable calcium isotopes recovered from fossil tooth enamel to compare the dietary ecology of hominins and other primates in the Turkana Basin 2-4 million years ago.

    • Jeremy E. Martin
    • , Théo Tacail
    •  & Vincent Balter
  • Article
    | Open Access

    The dynamics of how major clades and body plans arise and evolve in deep time remain poorly understood. Here, Simões et al. report major time lags between phases of rapid phenotypic change at the origin of major reptile lineages and periods of fast molecular change and adaptive radiation.

    • Tiago R. Simões
    • , Oksana Vernygora
    •  & Stephanie E. Pierce
  • Article
    | Open Access

    Parasitic interactions are difficult to document in the fossil record. Here, Zhang et al. analyze a large population of a Cambrian brachiopod and show it was frequently encrusted by tubes aligned to its feeding currents and that encrustation was associated with reduced biomass, suggesting a fitness cost.

    • Zhifei Zhang
    • , Luke C. Strotz
    •  & Glenn A. Brock
  • Article
    | Open Access

    Key events in human evolution are thought to have occurred between 3 and 2.5 Ma, but the fossil record of this period is sparse. Here, Alemseged et al. report a new fossil site from this period, Mille-Logya, Ethiopia, and characterize the geology, basin evolution and fauna, including specimens of Homo.

    • Zeresenay Alemseged
    • , Jonathan G. Wynn
    •  & Joseph Mohan
  • Article
    | Open Access

    The causes of the Upper Pleistocene megafauna extinction in Australia and New Guinea are debated, but fossil data are lacking for much of this region. Here, Hocknull and colleagues report a new, diverse megafauna assemblage from north-eastern Australia that persisted until ~40,000 years ago.

    • Scott A. Hocknull
    • , Richard Lewis
    •  & Rochelle A. Lawrence
  • Article
    | Open Access

    Complex macroscopic organisms are first found in the Ediacaran period, but their ecology during this time is not well understood. Here, Bobrovskiy et al. analyse biomarkers from Ediacaran sediments hosting macrofossils and find evidence for abundant algal food sources available for these organisms.

    • Ilya Bobrovskiy
    • , Janet M. Hope
    •  & Jochen J. Brocks
  • Article
    | Open Access

    Cloudinomorphs were one of the few groups to survive from the Ediacaran into the Cambrian, but they are known only from their external tubes. Here, Schiffbauer et al. report soft-tissue preservation of cloudinomorphs; the internal structures are interpreted as guts characteristic of bilaterians.

    • James D. Schiffbauer
    • , Tara Selly
    •  & Emily F. Smith
  • Article
    | Open Access

    The relative role of the Deccan Traps volcanic activity versus the role of the Chicxulub impact event in terms of potential contributions to the Cretaceous-Paleogene (K-Pg) mass extinction has been subject to longstanding debate. Here, the authors observe a global signal of abruptly increased ocean temperatures and elevated [Hg] in the same biogenic carbonate specimens, prior to the impact event but aligning with the onset of Deccan volcanism.

    • Kyle W. Meyer
    • , Sierra V. Petersen
    •  & Ian Z. Winkelstern
  • Article
    | Open Access

    Numerous feathered dinosaurs and early birds have been discovered from the Jurassic and Cretaceous, but the early evolution of feather-feeding insects is not clear. Here, Gao et al. describe a new family of ectoparasitic insects from 10 specimens found associated with feathers in mid-Cretaceous amber.

    • Taiping Gao
    • , Xiangchu Yin
    •  & Dong Ren
  • Article
    | Open Access

    The proximal femur is key for understanding locomotion in primates. Here, the authors analyze the evolution of the proximal femur in catarrhines, including a new Aegyptopithecus fossil, and suggest that Old World monkeys and hominoids diverged from an ancestral state similar to Aegyptopithecus.

    • Sergio Almécija
    • , Melissa Tallman
    •  & Erik R. Seiffert
  • Article
    | Open Access

    Little is known about the long-term dynamics of mesopelagic fish despite their large contribution to total fish biomass. Here, the authors analyze the Santa Barbara Basin otolith record and suggest that mesopelagic fish populations were large but fluctuated with surface climate over the last ~2000 years.

    • William A. Jones
    •  & David M. Checkley Jr.
  • Article
    | Open Access

    Late Middle Pleistocene (LMP) hominin fossils are scarce, limiting reconstruction of human evolution during this key period. Here, the authors use phylogenetic modelling to predict the modern human last common ancestor’s morphology and inform hypotheses of human origins by comparison to LMP fossils.

    • Aurélien Mounier
    •  & Marta Mirazón Lahr
  • Article
    | Open Access

    Sponge animals likely originated in the Precambrian, but their early spicular fossils are ambiguous. Here, Tang et al. report a new Cambrian sponge taxon with weakly biomineralized spicules and suggest that the poor Precambrian record may reflect the later evolution of biomineralization.

    • Qing Tang
    • , Bin Wan
    •  & Shuhai Xiao
  • Article
    | Open Access

    Hypsodonty is a durable pattern of dentition seen in mammals with abrasive diets. Here, Melo and colleagues describe new fossils of the stem-mammal Menadon besairiei from the Late Triassic, which show the convergent evolution of hypsodonty before mammals.

    • Tomaz P. Melo
    • , Ana Maria Ribeiro
    •  & Marina Bento Soares
  • Article
    | Open Access

    The transition from smectite to illite requires potassium incorporation, yet the role of microbes in facilitating K+ uptake remains debated, especially during the early Earth. Here, the authors suggest that the Paleoproterozoic microbial mats extracted potassium from sea water and induced localized illitization during early low-temperature diagenesis.

    • Jérémie Aubineau
    • , Abderrazak El Albani
    •  & Kurt O. Konhauser
  • Article
    | Open Access

    Little is known about the internal anatomy of early eyes. Here, Scholtz and colleagues show the internal eye structures from fossils of two genera of trilobites, which support an ancestral apposition eye with crystalline cones in Trilobita and a close affinity with Mandibulata.

    • Gerhard Scholtz
    • , Andreas Staude
    •  & Jason A. Dunlop
  • Article
    | Open Access

    Chemical imaging and spectroscopy have previously been used to identify eumelanin residue in fossils and infer dark coloration. Here, Manning and colleagues develop an approach to identify pheomelanin (red pigment) residues and ascertain their distribution in fossils.

    • Phillip L. Manning
    • , Nicholas P. Edwards
    •  & Roy A. Wogelius
  • Article
    | Open Access

    Our understanding of the origin of jaws is hampered by the poor fossil preservation of pharyngeal morphology. Here, Dearden et al. provide insight into the skull conditions of early jawed vertebrates through three-dimensional computed tomography imaging of a 415 million year old stem-chondrichthyan.

    • Richard P. Dearden
    • , Christopher Stockey
    •  & Martin D. Brazeau
  • Article
    | Open Access

    Previously, little direct evidence has been found to link large volcanic eruption events with the end-Permian mass extinction. Here, the authors find that mercury enrichment and isotope records in marine sections across the globe can be linked to increased volcanic activity, which resulted in the protracted Permian-Triassic biocrisis

    • Jun Shen
    • , Jiubin Chen
    •  & Noah J. Planavsky