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Specimens of four teuthid species, Loligosepia aalensis (Zieten), Jeletzkyteuthis agassizi (Deslongchamps), Teudopsis schuebleri (Quenstedt) and T. subcostata (Munster), are described from the Whitby Mudstone Formation (Toarcian) of North Yorkshire. Jeletzkyteuthis nom. nov. is erected to replace Loliginites Quenstedt which is nomenclaturally invalid. This teuthid fauna is found to be similar to that of southern England, Normandy and southern Germany.

• Read more about Teuthid cephalopods from the Lower Jurassic of Yorkshire

Previously described communities (' associations') from the Ludlow of the Welsh Borderland were subjected to cluster analysis on a PC microcomputer. Miscellaneous absence-presence data sets derived from the published information were analysed using different combinations of clustering algorithms, distance and similarity measurements, with and without Jaccard's coefficient of association. Variations in order of data entry produced major differences (chaotic behaviour) in clustering using unmodified data.

• Read more about Cluster analysis of previously described communities from the Ludlow of the Welsh Borderland

The bony fish Prohalecites is redescribed from new well-preserved material from the locality of Ca' del Frate (northern Italy), dated close to the Ladinian-Carnian boundary. A few poorly preserved specimens from the type locality, Perledo (Ladinian), have also been restudied. The specimens represent several ontogenetic stages as evidenced by vertebral column development, and it is concluded that in structure Prohalecites is intermediate between the Parasemionotidae and Dapedium plus the Pholidophoridac, being closer to the last two.

• Read more about The actinopterygian fish Prohalecites from the Triassic of northern Italy

Recent studies on ontogeny and shell microstructurc enable recognition of the inherent weakness of basing thecideidine taxonomy and phylogeny on morphological characteristics of separated brachial valves. Some previous assumptions are invalidated. The more robust components of lophophore supports are useful in determining relationships, but the form of the brachial lobes, because of their fragility, is less easy to establish, and, without the supporting evidence from sectioned complete shells, their value as taxonomic indicators is questionable.

• Read more about The classification, origin and phylogeny of thecideidine brachiopods

The ammonite faunas of the Woodbine Formation and lower part of the Eagle Ford Group of north-east and central Texas can be referred to five successive zonal assemblages of the standard sequence recognized for the southern part of the US Western Interior. The upper lower Cenomanian Forbesiceras brundrettei zone is represented by a limited assemblage in old collections believed to be from the Pepper Shale Member of the Woodbine, and from the Waco area. The middle Cenomanian Conlinoceras tarrantense zone is represented in the Tarrant Formation of the Eagle Ford in the area west of Dallas.

• Read more about Cenomanian ammonite faunas from the Woodbine Formation and lower part of the Eagle Ford Group, Texas

New SEM observations of topotype material of Palaeoperidinium cretaceum from the early Cretaceous of Alberta, Canada have allowed a complete description of this poorly known morphotype, including tabulation and plate overlap patterns. The features displayed by P. cretaceum show that, unlike other members of the genus, this morphotype cannot be interpreted as an extrathecal 'exophragm'. The life-cycle stage represented by P. cretaceum is discussed in relation to the life-cycle of modern dinoflagellates. It is suggested that P.

• Read more about Palaeoperidinium cretaceum: a brackish-water peridiniinean dinoflagellate from the early Cretaceous

Thirteen taxa of Permian crinoids are reported from Australia. These crinoids increase our knowledge of the cooler water Australian late Palaeozoic faunas, are dominantly sand substrate dwellers, and provide new fossils which support earlier correlations of recognized Permian strata in eastern and Western Australia. The early Permian age of several Australian species, which are also found in Timor, supports earlier views that the previously assigned late Permian age of the Timor crinoid-bearing Basleo Beds of the Maubisse Formation may be incorrect.

• Read more about New Permian crinoids from Australia

Bioimmuration is a poorly-known mode of preservation which results from organic overgrowth of sessile organisms. Soft-bodied organisms (and organisms with lightly mineralized skeletons) can be preserved if overgrown by other organisms possessing mineralized skeletons. These bioimmured fossils are visible on the attachment areas of the overgrowing organisms as natural moulds which sometimes become filled by diagenetic mineral growth to give a natural cast. Three types of bioimmuration are distinguished: substratum bioimmuration, epibiont bioimmuration and bioclaustration.

• Read more about Preservation of soft-bodied and other organisms by bioimmuration – a review

Soft-bodied ctenostome bryozoans, preserved as bioimmurations following overgrowth by encrusting organisms with hard skeletons, are described from the Middle and Upper Jurassic of England and Normandy. They include one new genus, Cardoarachnidium, and three new species, C. bantai, C. voigti and Arachnoidella abusensis. These and new bioimmured specimens of Arachnidium smithii (Phillips) show fine-scale details of original morphology as well as artefacts caused by partial collapse of zooids during overgrowth.

• Read more about Bioimmured ctenostomes from the Jurassic and the origin of the cheilostome Bryozoa

The apparatus of Pterospathodus species comprises Pa, Pb, PC, M and Sa/Sb elements. A more complete first symmetry transition series of Sa-Sc elements occurs in some related species, which are assigned to a new genus, Pranognathus. A sequence through the celloni and amorphognathoides biozones of Estonia has been sampled in detail, allowing documentation of sequential changes shown by Pterospathodus populations. The least conservative element is the Pa, in which gradual trends of increasing size, lateral process development and platform development prevail.

• Read more about Evolution, taxonomy and relationships of the Silurian conodont Pterospathodus