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We present the rationale for a cross‐disciplinary investigation addressing the ‘Devonian plant hypothesis’ which proposes that the evolutionary appearance of trees with deep, complex rooting systems represents one of the major biotic feedbacks on geochemical carbon cycling during the Phanerozoic. According to this hypothesis, trees have dramatically enhanced mineral weathering driving an increased flux of Ca²⁺ to the oceans and, ultimately, a 90% decline in atmospheric CO₂ levels through the Palaeozoic.

• Read more about Investigating Devonian trees as geo‐engineers of past climates: linking palaeosols to palaeobotany and experimental geobiology

The Ordovician and Silurian periods were times of major geological activity as regards palaeogeography, volcanism and climate change, the last of these evidenced by a series of cooling episodes and glaciations that climaxed in the Hirnantian (Late Ordovician). The presence of cryptospores in the Darriwilian (Middle Ordovician) marked the advent of higher plants on land. A critical survey of direct (mega‐ and microfossils) and some indirect evidence in succeeding rocks indicates the presence of algae, Bacteria, Cyanobacteria, Fungi, probable lichens, cryptophytes and basal tracheophytes.

• Read more about Could land‐based early photosynthesizing ecosystems have bioengineered the planet in mid‐Palaeozoic times?

Extant aplacophorans, a group of shell‐less vermiform molluscs, respire through appendages within or projecting from a posterior cavity. Respiratory structures differ between the subclasses Caudofoveata (ctenidia within the cavity) and Solenogastres (folds of the mantle itself). Acaenoplax hayae, a Silurian vermiform mollusc from the Herefordshire Lagerstätte, England, exhibits characteristics of both these groups.

• Read more about A novel respiratory architecture in the Silurian mollusc Acaenoplax

As the sister lineage of all other actinopterygians, the Middle to Late Devonian (Eifelian–Frasnian) Cheirolepis occupies a pivotal position in vertebrate phylogeny. Although the dermal skeleton of this taxon has been exhaustively described, very little of its endoskeleton is known, leaving questions of neurocranial and fin evolution in early ray‐finned fishes unresolved. The model for early actinopterygian anatomy has instead been based largely on the Late Devonian (Frasnian) Mimipiscis, preserved in stunning detail from the Gogo Formation of Australia.

• Read more about Endoskeletal structure in Cheirolepis (Osteichthyes, Actinopterygii), An early ray‐finned fish

Patterns of last occurrences of fossil species are often used to infer the tempo and timing of mass extinction, even though last occurrences generally precede the time of extinction. Numerical simulations with constant extinction demonstrate that last occurrences are not randomly distributed, but tend to cluster at subaerial unconformities, surfaces of forced regression, flooding surfaces and intervals of stratigraphical condensation, all of which occur in predictable stratigraphical positions.

• Read more about The stratigraphy of mass extinction

A new cryptostome bryozoan, Prophyllodictya simplex sp. nov., is described from the Nantzinkuan Formation (Lower Ordovician, lower Tremadoc) of Liujiachang, central China. This antedates the previously oldest known bryozoan by several million years. Colony morphology and the phylogenetic position of Prophyllodictya within Cryptostomata are explored.

• Read more about The oldest known bryozoan: Prophyllodictya (Cryptostomata) from the lower Tremadocian (Lower Ordovician) of Liujiachang, south‐western Hubei, central China

• Read more about Cyanobacteria and the Great Oxidation Event: evidence from genes and fossils

A review of all available specimens of fossil fishes from the classic Pennsylvanian Joggins locality of Nova Scotia, Canada, reveals the existence of a diverse community of chondrichthyans (xenacanthids, ctenacanthids and the enigmatic Ageleodus), acanthodians (gyracanthids), sarcopterygians (rhizodontids, megalichthyids, rhizodopsids and dipnoans) and actinopterygians (haplolepids).

• Read more about Early Pennsylvanian (Langsettian) fish assemblages from the Joggins Formation, Canada, and their implications for palaeoecology and palaeogeography

Characterized by atypical frontalmost appendages, leanchoiliids are early arthropods whose phylogenetic placement has been much debated. Morphological interpretations have differed, some of which concern critical characters such as the number of eyes and head appendages, but methodological approaches also have diverged. Here, we describe a new leanchoiliid, Yawunik kootenayi gen. et sp. nov., based on 42 specimens from the newly discovered Marble Canyon locality of the Burgess Shale (Kootenay National Park, British Columbia; middle Cambrian).

• Read more about A large new leanchoiliid from the Burgess Shale and the influence of inapplicable states on stem arthropod phylogeny

It is often assumed that life originated and diversified in the oceans prior to colonizing the land. However, environmental constraints in chemical evolution models point towards critical steps leading to the origin of life as having occurred in subaerial settings. The earliest fossil record does not include finds from terrestrial deposits, so much of our understanding about the presence of a terrestrial microbial cover prior to the Proterozoic is based on inference and geochemical proxies that indicate biospheric carbon cycling during the Archaean.

• Read more about The terrestrial biota prior to the origin of land plants (embryophytes): a review of the evidence