Eight sections of Cenomanian Chalk from Southern England have been examined for their Ostracoda. A total of 111 species and 3 sub-species have been found and these fall into 47 genera. 38 of these species have been previously described, 47 are new and the r e s t have been left under open nomenclature. A generalised distribution chart for some of the more important species has been drawn up and the distribution of species in each individual section has been compared to this chart. As a result it can be seen that Ostracoda can be very useful in stratigraphic work in the Cenomanian. Their stratigraphy has been related to the macrofossil zonations and in particular to the Foraminiferal zonation. The Ostracoda indicate that normal marine salinities prevailed throughout the Cenomanian period in Southern England and that temperatures were probably in excess of 10°C. Distinct changes in the ostracod fauna during the Cenomanian may be due in part to an increasing temperature but some of the changes appear to be related to an increase in sea depth. The presence of numerous small specimens in the Middle and Upper Cenomanian may indicate very quiet conditions of deposition during which oxygen levels were reduced. The ostracod fauna from Southern England has more affinity to the fauna described from the eastern part of the Paris Basin and the southern Alpine region of France than with other areas in France.

The exceptional preservation of the Lower Cambrian Chengjiang Lagerstätte provides a unique insight into the early evolution of vermiform animals. This study presents new vermiform taxa, describes their morphological features, hypothesizes possible modes of life and discusses phylogenetic relationships among early metazoan phyla. Morphological features are re-assessed in the Cambrian lobopodian Luolishania longicruris, and Miraluolishania haikouensis is considered to be its junior synonym. Evidence indicates that L. longicruris may have had a filter feeding lifestyle. Cladistic analysis suggests that Cambrian lobopodians are paraphyletic or even polyphyletic, and that L. longicruris with well developed sensory structures (‘antennae’, eyes and setae) and tagmosis (a distinct head and two trunk sections) may be an important representative of the stem lineage leading to arthropods. A new fossil priapulid Eximipriapulus globocaudatus is reported and described on the basis of specimens that reveal exquisite morphological details. Possible internal fertilization is suggested and a putative juvenile is described. Evidence indicates that the animal was an active burrower using a double-anchor strategy. Cladistic analysis resolves E. globocaudatus as one of the most derived Cambrian stem priapulids. The eyes of Hallucigenia fortis and Cardiodictyon catenulum are reported, along with a re-description of eyes from L. longicruris. Three visual units are found within the eyes of H. fortis and L. longicruris, suggesting that they resemble arthropod lateral visual organs and appear to represent the primitive visual systems of arthropods. Three new vermiform taxa, Acanthipos torquatus, Hamuscolex bosolveri, and Palaeomyzon discus are described. Comparison with extant taxa suggests that they may be stem group representatives of three separate phyla of extant parasitic worms. The oral disc of Palaeomyzon discus indicates a parasitic lifestyle. This study extends both the biodiversity and ecological diversity of known Early Cambrian ecosystems.

No description available.

Testudine remains are exceptionally scarce in the Middle Jurassic in Western Europe. However, in the Upper Jurassic testudines are represented by two pleurodiran families, the Notoemydidae and the Platychelidae, and cryptodires: the paracryptodiran Pleurosternidae (known only from fragmentary remains from the continent and a single taxon from the Portland Limestone Formation), and the eucryptodiran families Eurysternidae and the Plesiochelyidae. The sudden appearance of these families in marine deposits of the European Upper Jurassic suggests that they constitute one of the earliest marine radiations of testudines. The work described herein is the first study of European Late Jurassic testudines that combines multiple aspects of osteology, palaeopathologies, taphonomy and functional morphology. The most significant testudine remains in terms of these aspects are from the Kimmeridgian Reuchenette Formation, Switzerland, and the Tithonian Solnhofen Limestone Formation, Germany. The synonymy of Tholemys Andrews, 1921, with Plesiochelys Rütimeyer, 1873, is refuted. Thalassemys chelonia, previously a nomen nudum, is described and figured here for the first time. A new genus and species of eurysternid unique to the British Isles is described and figured. The first record of the range and extent of palaeopathologies in Late Jurassic testudines, and a new classification scheme is provided. An experimental method using a moderately controlled and monitored outdoor environment illustrates differences between natural disarticulation and predation or scavenger attack, preferential scavenging activity and the effects of resistant integuments within a carcass. Upper Jurassic testudines are preserved in a variety of styles, reflecting different taphonomic pathways. The Kimmeridge Clay represents an attritional accumulation of testudines, whilst the accumulation of the Solnhofen Limestone Formation is a combination of attritional and catastrophic. The process which resulted in the accumulation of the Reuchenette Formation remains enigmatic. For the first time, the relationship between the length of the mantis relative to the length of the arm has been applied to Late Jurassic testudines as a method of determining habitat preference. No Late Jurassic testudines included in the analysis had forelimbs with ratios equivalent to fully terrestrial or fully marine turtles, but most appear to have been moderately adapted for the neritic (shallow to coastal marine) environment, with increased mobility and terrestrial ability when compared to extant marine turtles. These factors would probably be a selective advantage in a coastal island environment, where widespread migrations were not required, but large marine predators (e. g. Machimosaurus) were present.

The Lower Jurassic species of Spiriferina d'Orbigny are revised in this thesis. Twenty-six species and one subspecies are described from Europe, North and South America, Africa, Asia and Indonesia, based on morphological, stratigraphical and ecological observations. Detailed examination permits the introduction of new taxa comprising two subgenera, Plicatispiriferina and a nominate subgenus, one species S. thorncombensis and a subspecies S. tumida chilensis, A key is included for easy identification. All species have been traced as far as possible to their original publication and aided by museum, reference and collections made by the writer. The composition and status of the genus, subgenera and species including the origin and history of the type-species are discussed in detail. Serial transverse grinding has been used to study the internal structure of all but the rarest species and depicted as detailed drawings made from acetate peels. The geographical distribution of certain and distinctive species is plotted and discussed. It is suggested that a distinctive province is recognisable in the south-eastern Mediterranean part of Tethys. Their evolutionary relationship to those spiriferinids of the Triassic is discussed and a scheme proposed for the classification of the superfamily Spiriferinacea Davidson. The ecological and stratigraphical distribution is considered at length and in conclusion a number of possible explanations are suggested for their mass extinction in the Upper Liss.

No description available.

No description available.

No description available.

No description available.

No description available.