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Black shales of the lower member of the Carnian Xiaowa Formation (previously known as the Wayao Member of the Falang Formation or as the Wayao Formation) in the Guanling area, Guizhou Province, south-west China, are yielding a rich marine reptile fauna and exceptional remains of pelagic crinoids. The black shales represent deposition on the drowned southern margin of the Yangtze Platform during a Maximum Flooding Interval.

• Read more about The Late Triassic black shales of the Guanling area, Guizhou Province, South-West China: a unique marine reptile and pelagic crinoid fossil Lagerstätte

Correct interpretation of the Ediacara biota is critical to our understanding of the dramatic events at the base of the Cambrian. We review here the history of thought and examine new laser images of the holotype of Charnia masoni Ford, 1958, of the Ediacara biota, in terms of growth and development. Growth and development are argued to provide critical tools for understanding this and other enigmatic fossil groups. We show that Charnia cannot be related to the modern cnidarian group, the sea pens, with which it has for so long been compared, because they have opposite growth polarities.

• Read more about Charnia at 50: developmental models for Ediacaran fronds

A remarkable new fossil horseshoe crab, Lunataspis aurora gen. et sp. nov., from recently discovered Upper Ordovician (c. 445 Ma) shallow marine Konservat-Lagerstätten deposits in Manitoba (Canada), is characterized by fusion of opisthosomal tergites into two sclerites. A broad mesosoma of six or seven fused segments, followed by a narrow metasoma of three reduced segments, represents an advanced transitional condition in the development of the xiphosurid thoracetron.

• Read more about The oldest horseshoe crab: a new xiphosurid from Late Ordovician Konservat-Lagerstätten deposits, Manitoba, Canada

Xenoposeidon proneneukos gen. et sp. nov. is a neosauropod represented by BMNH R2095, a well-preserved partial mid-to-posterior dorsal vertebra from the Berriasian-Valanginian Hastings Beds Group of Ecclesbourne Glen, East Sussex, England. It was briefly described by Lydekker in 1893, but it has subsequently been overlooked. This specimen's concave cotyle, large lateral pneumatic fossae, complex system of bony laminae and camerate internal structure show that it represents a neosauropod dinosaur.

• Read more about An unusual new neosauropod dinosaur from the Lower Cretaceous Hastings Beds Group of East Sussex, England

Dicynodont therapsids were near-ubiquitous components of Permo-Triassic terrestrial faunas, but the morphology of many of the nominal species remains poorly understood. Here we provide a detailed redescription of the cranium of the poorly known Dolichuranus primaevus from the Middle Triassic Omingonde Formation of Namibia, based on both the holotype and previously undescribed referred specimens. We identify a number of autapomorphic characters of D. primaevus and provide a revised taxon diagnosis.

• Read more about Dolichuranus primaevus (Therapsida: Anomodontia) from the Middle Triassic of Namibia and its phylogenetic relationships

During the Triassic, some 250-200 million years ago, the basal archosaurs showed a transition from sprawling to erect posture. Past studies focused on changes in bone morphology, especially on the joints, as they reorientated from a sprawling to an erect posture.

• Read more about Evolution of hindlimb posture in archosaurs: limb stresses in extinct vertebrates

Twenty-nine species of bryozoans from the Upper Ordovician-Lower Silurian Pin Formation (Spiti, India) have been identified. Eight of these are new: Trematopora minima, Ulrichostylus bhargavai, Ptilodictya exiliformis, Phaenopora ordinarius, Oanduellina himalayaica, Pesnastylus? vesiculosum, Ralfina? originalis and Pinocladia triangulata. The fossil record and facies analyses of the area investigated indicate shallow-water conditions within the subtropical-tropical realm.

• Read more about Upper Ordovician bryozoans of the Pin Formation (Spiti Valley, northern India)

The extant, introduced razor shell Ensis americanus (Binney) is a burrowing inhabitant of sandy, shallow-water substrates off the North Sea and Wadden Sea coasts of The Netherlands and adjacent areas. Three articulated shells with broken valves, collected from the strandline at Zandvoort, Noord-Holland, in April 2006 have dense skeletozoan infestations of the barnacle Balanus crenatus Brugiere on the outer and inner surfaces of all valves. Such infestations must have occurred after death of the bivalve, decomposition of the soft tissues (but not the ligament) and disinterment of the shells.

• Read more about A cautionary tale: razor shells, acorn barnacles and palaeoecology

Palaeozoic and Mesozoic cephalopod conchs occasionally reveal dark organic coatings at the aperture. A number of these coatings, including still unrecorded examples, are described, figured and interpreted herein. On the basis of elemental analysis, actualistic comparison and a comparison with Triassic bivalves, some of these coatings are shown to consist of apatite and primarily probably of conchiolin (and also probably melanin).

• Read more about Ammonoid shell structures of primary organic composition

An essential tool in micropalaeontological studies is analysis and imaging using a scanning electron microscope (SEM). It is commonly necessary to coat the sample with a thin layer of gold or gold-palladium alloy in order to prevent charging of the surface, to promote the emission of secondary electrons so that the specimen conducts evenly, and to provide a homogeneous surface for analysis and imaging. However, coating a specimen with gold is a semi-destructive process that masks the surface of specimens, and a common curatorial practice is to prohibit coating of important specimens.

• Read more about Removing gold coating from SEM samples