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Biodiversity today has the unusual property that 85% of plant and animal species live on land rather than in the sea, and half of these live in tropical rainforests. Anexplosive boost to terrestrial diversity occurred from c. 100–50 million years ago, the Late Cretaceous and early Palaeogene. During this interval, the Earth-life system on land was reset, and the biosphere expanded to a new level of productivity, enhancing the capacity and species diversity of terrestrial environments. This boost in terrestrial biodiversity coincided with innovations in flowering plant biology and evolutionary ecology, including their flowers and efficiencies in reproduction; coevolution with animals, especially pollinators and herbivores; photosynthetic capacities; adaptability; and ability to modify habitats. The rise of angiosperms triggered a macroecological revolution on land and drove modern biodiversity in a secular, prolonged shift to new, high levels, a series of processes we name here the Angiosperm Terrestrial Revolution.

It is often postulated that mammalian diversity was suppressed during the Mesozoic Era and increased rapidly after the Cretaceous–Palaeogene (K–Pg) extinction event. We test this hypothesis by examining macroevolutionary patterns in early therian mammals, the group that gave rise to modern placentals and marsupials. We assess morphological disparity and dietary trends using morphometric analyses of lower molars, and we evaluate generic level taxonomic diversity patterns using techniques that account for sampling biases. In contrast with the suppression hypothesis, our results suggest that an ecomorphological diversification of therians began 10–20 Myr prior to the K–Pg extinction event, led by disparate metatherians and Eurasian faunas. This diversification is concurrent with ecomorphological radiations of multituberculate mammals and flowering plants, suggesting that mammals as a whole benefitted from the ecological rise of angiosperms. In further contrast with the suppression hypothesis, therian disparity decreased immediately after the K–Pg boundary, probably due to selective extinction against ecological specialists and metatherians. However, taxonomic diversity trends appear to have been decoupled from disparity patterns, remaining low in the Cretaceous and substantially increasing immediately after the K–Pg extinction event. The conflicting diversity and disparity patterns suggest that earliest Palaeocene extinction survivors, especially eutherian dietary generalists, underwent rapid taxonomic diversification without considerable morphological diversification.

Pelagic ecosystem function is integral to global biogeochemical cycling, and plays a major role in modulating atmospheric CO2 concentrations (pCO2). Uncertainty as to the effects of human activities on marine ecosystem function hinders projection of future atmospheric pCO2. To this end, events in the geological past can provide informative case studies in the response of ecosystem function to environmental and ecological changes. Around the Cretaceous–Palaeogene (K–Pg) boundary, two such events occurred: Deccan large igneous province (LIP) eruptions and massive bolide impact at the Yucatan Peninsula. Both perturbed the environment, but only the impact coincided with marine mass extinction. As such, we use these events to directly contrast the response of marine biogeochemical cycling to environmental perturbation with and without changes in global species richness. We measure this biogeochemical response using records of deep-sea carbonate preservation. We find that Late Cretaceous Deccan volcanism prompted transient deep-sea carbonate dissolution of a larger magnitude and timescale than predicted by geochemical models. Even so, the effect of volcanism on carbonate preservation was slight compared with bolide impact. Empirical records and geochemical models support a pronounced increase in carbonate saturation state for more than 500 000 years following the mass extinction of pelagic carbonate producers at the K–Pg boundary. These examples highlight the importance of pelagic ecosystems in moderating climate and ocean chemistry.

Sexual selection often favours investment in expensive sexual traits that help individuals compete for mates. In a rapidly changing environment, however, allocation of resources to traits related to reproduction at the expense of those related to survival may elevate extinction risk. Empirical testing of this hypothesis in the fossil record, where extinction can be directly documented, is largely lacking. The rich fossil record of cytheroid ostracods offers a unique study system in this context: the male shell is systematically more elongate than that of females, and thus the sexes can be distinguished, even in fossils. Using mixture models to identify sex clusters from size and shape variables derived from the digitized valve outlines of adult ostracods, we estimated sexual dimorphism in ostracod species before and after the Cretaceous/Palaeogene mass extinction in the United States Coastal Plain. Across this boundary, we document a substantial shift in sexual dimorphism, driven largely by a pronounced decline in the taxa with dimorphism indicating both very high and very low male investment. The shift away from high male investment, which arises largely from evolutionary changes within genera that persist through the extinction, parallels extinction selectivity previously documented during the Late Cretaceous under a background extinction regime. Our results suggest that sexual selection and the allocation of resources towards survival versus reproduction may be an important factor for species extinction during both background and mass extinctions.

Free-ranging common tenrecs, Tenrec ecaudatus, from sub-tropical Madagascar, displayed long-term (nine months) hibernation which lacked any evidence of periodic interbout arousals (IBAs). IBAs are the dominant feature of the mammalian hibernation phenotype and are thought to periodically restore long-term ischaemia damage and/or metabolic imbalances (depletions and accumulations). However, the lack of IBAs in tenrecs suggests no such pathology at hibernation Tbs > 22°C. The long period of tropical hibernation that we report might explain how the ancestral placental mammal survived the global devastation that drove the dinosaurs and many other vertebrates to extinction at the Cretaceous–Palaeogene boundary following a meteorite impact. The genetics and biochemistry of IBAs are of immense interest to biomedical researchers and space exploration scientists, in the latter case, those envisioning a hibernating state in astronauts for deep space travel. Unravelling the physiological thresholds and temperature dependence of IBAs will provide new impetus to these research quests.

Molecular phylogenies suggest some major radiations of open-ocean fish clades occurred roughly coincident with the Cretaceous–Palaeogene (K/Pg) boundary, however the timing and nature of this diversification is poorly constrained. Here, we investigate evolutionary patterns in ray-finned fishes across the K/Pg mass extinction 66 million years ago (Ma), using microfossils (isolated teeth) preserved in a South Pacific sediment core spanning 72–43 Ma. Our record does not show significant turnover of fish tooth morphotypes at the K/Pg boundary: only two of 48 Cretaceous tooth morphotypes disappear at the event in the South Pacific, a rate no different from background extinction. Capture–mark–recapture analysis finds two pulses of origination in fish tooth morphotypes following the mass extinction. The first pulse, at approximately 64 Ma, included short-lived teeth, as well as forms that contribute to an expansion into novel morphospace. A second pulse, centred at approximately 58 Ma, produced morphotype novelty in a different region of morphospace from the first pulse, and contributed significantly to Eocene tooth morphospace occupation. There was no significant increase in origination rates or expansion into novel morphospace during the early or middle Eocene, despite a near 10-fold increase in tooth abundance during that interval. Our results suggest that while the K/Pg event had a minor impact on fish diversity in terms of extinction, the removal of the few dominant Cretaceous morphotypes triggered a sequence of origination events allowing fishes to rapidly diversify morphologically, setting the stage for exceptional levels of ray-finned fish diversity in the Cenozoic.

The discovery of huge gas plays in the deep-water geological systems (e.g., eastern Mediterranean, North America, southern Pacific, etc.), along with improving the exploration technique, have encouraged the exploration campaign to resume the exploration activities in similar contexts around the globe. As such, the onshore-offshore Taranaki Basin, which is the sole gas-bearing basin in New Zealand, has an extensive exploration campaign focused on the onshore parts of the basin, whereas the deep-water regions are still poorly explored. Among these petroleum systems, the architecture of the Palaeogene-Neogene reservoirs in the Western offshore Taranaki Basin, and the implication of depositional and diagenetic attributes on their reservoir quality are yet obscure. To address the above uncertainties, we integrate seismic-stratigraphy, well log analysis, and petrographic investigations to define the stratigraphic evolution and reservoir facies distribution, revealing the factors controlling the development of their pore systems. This petrophysical analysis reveals that, the sandstones of Farewell F have the best reservoir quality within the Palaeocene transgressive succession. Furthermore, clastic-dominated shelf conditions continued during the Eocene, where the transgressive sandstones of Kaimiro D reservoir presented the main reservoir within the Eocene succession. However, due to ineffective migration, both reservoirs are tested and considered non gas-producing. Results of this testing suggested that, upwards, a deep-water sedimentation prevailed during the Middle Miocene, resulting in the deposition of basin-floor fan lobes/sandstones of the Manganui Formation and its equivalent Moki Formation, which could host the most potential reservoir targets due to the presence of many sand lobes. Therefore, the present study recommends testing these sand lobes. Finally, our findings highlight the significance of reanalyzing and integrating seismic stratigraphy, well logging, and petrography in exploring the untapped potential reservoir zones in the Taranaki Basin that can be used globally in similar settings.

The early Paleogene (56–48 Myr) provides valuable information about the Earth’s climate system in an equilibrium high \\[p_{{\\rm{CO}}_2}\\] world. High ocean temperatures have been reconstructed for this greenhouse period, but land temperature estimates have been cooler than expected. This mismatch between marine and terrestrial temperatures has been difficult to reconcile. Here we present terrestrial temperature estimates from a newly calibrated branched glycerol dialkyl glycerol tetraether-based palaeothermometer in ancient lignites (fossilized peat). Our results suggest early Palaeogene mid-latitude mean annual air temperatures of 23–29 °C (with an uncertainty of ± 4.7 °C), 5–10 °C higher than most previous estimates. The identification of archaeal biomarkers in these same lignites, previously observed only in thermophiles and hyperthermophilic settings, support these high temperature estimates. These mid-latitude terrestrial temperature estimates are consistent with reconstructed ocean temperatures and indicate that the terrestrial realm was much warmer during the early Palaeogene than previously thought.

Early lagomorphs are central to our understanding of how the brain evolved in Glires (rodents, lagomorphs and their kin) from basal members of Euarchontoglires (Glires + Euarchonta, the latter grouping primates, treeshrews, and colugos). Here, we report the first virtual endocast of the fossil lagomorph Megalagus turgidus , from the Orella Member of the Brule Formation, early Oligocene, Nebraska, USA. The specimen represents one of the oldest nearly complete lagomorph skulls known. Primitive aspects of the endocranial morphology in Megalagus include large olfactory bulbs, exposure of the midbrain, a small neocortex and a relatively low encephalization quotient. Overall, this suggests a brain morphology closer to that of other basal members of Euarchontoglires (e.g. plesiadapiforms and ischyromyid rodents) than to that of living lagomorphs. However, the well-developed petrosal lobules in Megalagus , comparable to the condition in modern lagomorphs, suggest early specialization in that order for the stabilization of eye movements necessary for accurate visual tracking. Our study sheds new light on the reconstructed morphology of the ancestral brain in Euarchontoglires and fills a critical gap in the understanding of palaeoneuroanatomy of this major group of placental mammals.

Large-scale magmatic events like the emplacement of the North Atlantic Igneous Province (NAIP) are often coincident with periods of extreme climate change such as the Palaeocene–Eocene Thermal Maximum (PETM). One proxy for volcanism in the geological record that is receiving increased attention is the use of mercury (Hg) anomalies. Volcanic eruptions are among the dominant natural sources of Hg to the environment; thus, elevated Hg∕TOC values in the sedimentary rock record may reflect an increase in volcanic activity at the time of deposition. Here we focus on five continental shelf sections located around the NAIP in the Palaeogene. We measured Hg concentrations, total organic carbon (TOC) contents, and δ13C values to assess how Hg deposition fluctuated across the PETM carbon isotope excursion (CIE). We find a huge variation in Hg anomalies between sites. The Grane field in the North Sea, the most proximal locality to the NAIP analysed, shows Hg concentrations up to 90 100 ppb (Hg∕TOC = 95 700 ppb wt %−1) in the early Eocene. Significant Hg∕TOC anomalies are also present in Danish (up to 324 ppb wt %−1) and Svalbard (up to 257 ppb wt %−1) sections prior to the onset of the PETM and during the recovery period, while the Svalbard section also shows a continuous Hg∕TOC anomaly during the body of the CIE. The combination with other tracers of volcanism, such as tephra layers and unradiogenic Os isotopes, at these localities suggests that the Hg∕TOC anomalies reflect pulses of magmatic activity. In contrast, we do not observe clear Hg anomalies on the New Jersey shelf (Bass River) or the Arctic Ocean (Lomonosov Ridge). This large spatial variance could be due to more regional Hg deposition. One possibility is that phreatomagmatic eruptions and hydrothermal vent complexes formed during the emplacement of sills led to submarine Hg release, which is observed to result in limited distribution in the modern era. The Hg∕TOC anomalies in strata deposited prior to the CIE may suggest that magmatism linked to the emplacement of the NAIP contributed to the initiation of the PETM. However, evidence for considerable volcanism in the form of numerous tephra layers and Hg∕TOC anomalies post-PETM indicates a complicated relationship between LIP volcanism and climate. Factors such as climate system feedbacks, changes to the NAIP emplacement style, and/or varying magma production rates may be key to both the onset and cessation of hyperthermal conditions during the PETM. However, processes such as diagenesis and organic matter sourcing can have a marked impact on Hg∕TOC ratios and need to be better constrained before the relationship between Hg anomalies and volcanic activity can be considered irrefutable.