Palaeoecology of the Hiraiso Formation (Miyagi Prefecture, Japan) and implications for the recovery following the end-Permian mass extinction.

The Hiraiso Formation of northeast Japan represents an important and under-explored archive of Early Triassic marine ecosystems. Here, we present a palaeoecological analysis of its benthic faunas in order to explore the temporal and spatial variations of diversity, ecological structure and taxonomic composition. In addition, we utilise redox proxies to make inferences about the redox state of the depositional environments.

Global record of "ghost" nannofossils reveals plankton resilience to high CO and warming.

Predictions of how marine calcifying organisms will respond to climate change rely heavily on the fossil record of nannoplankton. Declines in calcium carbonate (CaCO) and nannofossil abundance through several past global warming events have been interpreted as biocalcification crises caused by ocean acidification and related factors. We present a global record of imprint-or "ghost"-nannofossils that contradicts this view, revealing exquisitely preserved nannoplankton throughout an inferred Jurassic biocalcification crisis.

Modelling determinants of extinction across two Mesozoic hyperthermal events.

The Late Triassic and Early Toarcian extinction events are both associated with greenhouse warming events triggered by massive volcanism. These Mesozoic hyperthermals were responsible for the mass extinction of marine organisms and resulted in significant ecological upheaval. It has, however, been suggested that these events merely involved intensification of background extinction rates rather than significant shifts in the macroevolutionary regime and extinction selectivity.

Marine Metazoan Modern Mass Extinction: Improving Predictions by Integrating Fossil, Modern, and Physiological Data.

Evolution, extinction, and dispersion are fundamental processes affecting marine biodiversity. Until recently, studies of extant marine systems focused mainly on evolution and dispersion, with extinction receiving less attention. Past extinction events have, however, helped shape the evolutionary history of marine ecosystems, with ecological and evolutionary legacies still evident in modern seas.

Ecological impact of the end-Cretaceous extinction on lamniform sharks.

Lamniform sharks are apex marine predators undergoing dramatic local and regional decline worldwide, with consequences for marine ecosystems that are difficult to predict. Through their long history, lamniform sharks have faced widespread extinction, and understanding those 'natural experiments' may help constrain predictions, placing the current crisis in evolutionary context. Here we show, using novel morphometric analyses of fossil shark teeth, that the end-Cretaceous extinction of many sharks had major ecological consequences.

Subsequent biotic crises delayed marine recovery following the late Permian mass extinction event in northern Italy.

The late Permian mass extinction event was the largest biotic crisis of the Phanerozoic and has the longest recovery interval of any extinction event. It has been hypothesised that subsequent carbon isotope perturbations during the Early Triassic are associated with biotic crises that impeded benthic recovery. We test this hypothesis by undertaking the highest-resolution study yet made of the rock and fossil records of the entire Werfen Formation, Italy.

The oldest post-Palaeozoic Crinoid and Permian-Triassic origins of the Articulata (Echinodermata).

The Crinoidea are the most primitive class of living echinoderms, and suffered a severe crisis during the Late Permian mass extinction event. All post-Palaeozoic crinoids, including living species, belong to the Articulata, and morphological and recent molecular studies demonstrate that they form a monophyletic clade. The Articulata originated from Palaeozoic cladid crinoids, but the nature and timing of their origination remains obscure.

Ecological succession of a Jurassic shallow-water ichthyosaur fall.

After the discovery of whale fall communities in modern oceans, it has been hypothesized that during the Mesozoic the carcasses of marine reptiles created similar habitats supporting long-lived and specialized animal communities. Here, we report a fully documented ichthyosaur fall community, from a Late Jurassic shelf setting, and reconstruct the ecological succession of its micro- and macrofauna. The early 'mobile-scavenger' and 'enrichment-opportunist' stages were not succeeded by a 'sulphophilic stage' characterized by chemosynthetic molluscs, but instead the bones were colonized by microbial mats that attracted echinoids and other mat-grazing invertebrates.

Hierarchical random walks in trace fossils and the origin of optimal search behavior.

Efficient searching is crucial for timely location of food and other resources. Recent studies show that diverse living animals use a theoretically optimal scale-free random search for sparse resources known as a Lévy walk, but little is known of the origins and evolution of foraging behavior and the search strategies of extinct organisms. Here, using simulations of self-avoiding trace fossil trails, we show that randomly introduced strophotaxis (U-turns)--initiated by obstructions such as self-trail avoidance or innate cueing--leads to random looping patterns with clustering across increasing scales that is consistent with the presence of Lévy walks.

Isotopic evidence for long term warmth in the Mesozoic.

Atmospheric CO2 concentrations appear to have been considerably higher than modern levels during much of the Phanerozoic and it has hence been proposed that surface temperatures were also higher. Some studies have, however, suggested that Earth's temperature (estimated from the isotopic composition of fossil shells) may have been independent of variations in atmospheric CO2 (e.g.

The impact of global warming and anoxia on marine benthic community dynamics: an example from the Toarcian (Early Jurassic).

The Pliensbachian-Toarcian (Early Jurassic) fossil record is an archive of natural data of benthic community response to global warming and marine long-term hypoxia and anoxia. In the early Toarcian mean temperatures increased by the same order of magnitude as that predicted for the near future; laminated, organic-rich, black shales were deposited in many shallow water epicontinental basins; and a biotic crisis occurred in the marine realm, with the extinction of approximately 5% of families and 26% of genera. High-resolution quantitative abundance data of benthic invertebrates were collected from the Cleveland Basin (North Yorkshire, UK), and analysed with multivariate statistical methods to detect how the fauna responded to environmental changes during the early Toarcian.

Photic zone euxinia during the Permian-triassic superanoxic event.

Carbon and sulfur isotopic data, together with biomarker and iron speciation analyses of the Hovea-3 core that was drilled in the Perth Basin, Western Australia, indicate that euxinic conditions prevailed in the paleowater column during the Permian-Triassic superanoxic event. Biomarkers diagnostic for anoxygenic photosynthesis by Chlorobiaceae are particularly abundant at the boundary and into the Early Triassic. Similar conditions prevailed in the contemporaneous seas off South China.