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The principal problem in biostratigraphical theory is a justification for using fossils to identify isochronous horizons. Biostratigraphers establish the sequential order of fossil events but there is no theoretical justification for equating constancy in stratigraphical position (homotaxy) with constancy in time of deposition. The problem is important as the way in which it is solved greatly influences the direction of biostratigraphical research. A partial solution is to use homotaxy as a weak test for diachroneity.

• Read more about Homotaxy and biostratigraphical theory

The five genera and thirteen named species of edrioasteroid from the Cambrian are reviewed and, where necessary, redescribed. All are interpreted as sessile suspension feeders, with an external system of radial water vessels and tube feet that functioned in opening the cover plate sheets. The relationships of these five genera to one another and to other edrioasteroid groups is analysed and a revised classification of the Edrioasteroidea is proposed. Stromatocystites has fewest autapomorphic characters and is placed as primitive sister group to the other four genera.

• Read more about Cambrian eleutherozoan echinoderms and the early diversification of edrioasteroids

Published guidance on the preparation of ultrathin sections of biological material rarely gives sufficient detail to enable fossil material in general and graptolite material in particular to be prepared to a consistently high standard. The crucial steps relative to pre-microtoming, ultramicrotoming, and post-microtome work, including museum storage, are described together with the 'tricks of the trade' that, taken in total, result in successful micrographs.

• Read more about Optimum preparation, preservation, and processing techniques for graptolite electron microscopy

Twenty-two multi-element conodont species are described from Caradoc-Ashgill (Ordovician) strata sampled throughout Wales and the Welsh Borderland. Plectodina bullhillensis, P. bergstroemi, and Prioniodus deani are described as new species. Strata from the Costonian to Soudleyan stages appear to lie within the tvaerensis conodont Biozone, with Longvillian to ?Onnian strata in the superbus Biozone, and Pusgillian to Hirnantian strata in the ordovicicus Biozone, although in no sections are the zonal boundaries sharply defined.

• Read more about Caradoc–Ashgill conodont faunas from Wales and the Welsh Borderland

Two species otlsocrinus, one of which is new (Isocrinus (Chladocrinus) hanaii sp. nov.), are described from the upper Aptian of the Miyako Group, Northeast Japan. The skeletons of I. (C.) hanaii are preserved intact at several localities, so it is presumed that they were rapidly buried either alive or shortly after death, the animals having lived on a sandy bottom in agitated water.

• Read more about Early Cretaceous Isocrinus from northeast Japan

The forelimb and pectoral girdle of Struthiomimus altus are described for the first time. The ornithomimid pectoral girdle differs from that of other theropods in having a higher scapular prominence (acromion process), an anterior flange on the supraglenoid buttress, and a narrow, attenuated coracoid.Osteological and myological comparisons with recent reptiles and birds, combined with muscle scar evidence, suggests that the primary girdle of Struthiomimus was oriented somewhat laterally, as in recent crocodiles and lizards, and that it was mobile with respect to the body wall.

• Read more about Structure and function of the pectoral girdle and forelimb of Struthiomimus altus (Theropoda: Ornithomimidae)

Two new species of herbaceous lycopods, Haskinsia sagittata and Colpodexylon cachiriense, are described from Devonian strata in the Cano Grande-Rio Cachiri region (north central Sierra de Perija) of Venezuela. The recently discovered diverse assemblage of megafossils also contains the first record of progymnosperms in South America as well as possible cladoxylaleans. The lycopods exhibit a number of preservation forms, and these are related to their putative preservational history. The assemblage is of Laurentian aspect, showing greatest similarity to those from New York State.

• Read more about Two new species of herbaceous lycopods from the Devonian of Venezuela with comments on their taphonomy

Bilobate burrows lying parallel to bedding are described from a shallow-water sandstone. The burrows are linked to structures produced by oblique movement through the sediment, the outlines of these suggesting that the animal responsible was a xiphosurid, perhaps Bellinurus. The internal structure of the burrows shows transverse markings on either side of a median furrow but the external surfaces are poorly preserved and it is uncertain to which of the existing bilobate ichnogenera the trace fossil belongs. It is provisionally referred to Aulichnites Fenton and Fenton, 1937 as Aulichnites?

• Read more about Xiphosurid burrows from the Lower Coal Measures (Westphalian A) of West Yorkshire

A pilot study comparing ostracode faunas from the North American and European plates dispels the notion that Ordovician ostracodes show strict endemicity. Problems addressed include: how some ostracodes managed to cross the Ordovician lapetus Ocean estimated at 3,000 + km wide; and why some of their ostracode counterparts in the Silurian show provinciality? It is concluded that, from the point of view of ostracode dispersal, opposing Ordovician plates may have been in closer effective geographical proximity than hitherto supposed.

• Read more about Ostracodes across the Iapetus Ocean

Records of occurrence are presented in the form of two new taxa of peridinioid dinoflagellate cysts and twenty-three comparison records from Upper Wealden strata of Barremian age in the British Geological Survey's Warlingham Borehole, Surrey. Because these well-preserved dinocysts are not accompanied by any other dinocyst palynomorphs, their presence is interpreted as a short-lived and local record of very low palaeo-salinity.

• Read more about Wealden occurrence of an isolated Barremian dinocyst facies