Archive

Eight morphological types of microsculpture have been recognized on the outer shell surface of well-preserved ammonites. They consist mainly of wrinkles and creases which were developed on a pliant material. They are interpreted as the result of compressive stresses which occurred on a free (i.e. uncalcified) periostracum. This is the first evidence of periostracal development in ammonoids, and its relation to the shell suggests a mode of calcification similar to present-day molluscs. This periostracum was also attached to the soft body along longitudinal lines.

• Read more about A model for the morphogenesis of ribs in ammonites inferred from associated microsculptures

A new uncalcified arthropod, Soomaspis, is described from the latest Ordovician Soom Shale of South Africa. It is included with other primitive and uncalcified trilobites in the family Naraoiidae, the composition and evolution of which are re-evaluated. Naraoiids are considered to have arisen by the heterochronic process of hypermorphosis, whereas Agnostida, to which they bear a superficial resemblance, are progenetic. The place of Soomaspis and naraoiids within the trilobite-like arthropods is analysed cladistically; they comprise a sister group of the rest of the clade.

• Read more about A new Ordovician anthropod, Soomaspis, and the agnostid problem

The general morphological features of arthropod trackways are defined under headings of trackway width, imprint morphologies, track rows, repeat distance, symmetry, continuous marks, discontinuous marks and trackway curvature. These features are combined in a standard format for use in trackway description and diagnosis. The data can be used in a Trackway Data System, in which trackway attributes are represented by a formula of numbers and letters.

• Read more about A draft system for the identification and description of arthropod trackways

Detailed sampling of Palaeogene sediments from Barbados has resulted in the rediscovery of the type locality of the rare siliceous dinoflagellate Peridinites. Electron microscopic examination has revealed that Peridinites can only be interpreted as the remains of dinoflagellate motile thecate cells, rather than hypnozygotic cysts; it thus represents the first unequivocal example of a fossil dinoflagellate theca. Dinoflagellate cysts have also been found and identified as belonging to Lithoperidinium.

• Read more about Siliceous dinoflagellate thecal fossils from the Eocene of Barbados

Two new Triassic isopod crustaceans from the southern Calcareous Alps are described on the basis of well preserved specimens. This small assemblage comes from the late Norian Calcare di Zorzino, which is especially well-known for its vertebrate fauna. At least two new genera of Isopoda are present, here assign to the Sphaeromatidae and Serolidae. Triassphaeroma magnificum is erected for specimens whose single first pleonal unit comprises five fused tergites, a feature peculiar to Sphaeromatidae.

• Read more about New Triassic isopod crustaceans from northern Italy

The apparatus composition and architecture of the coniform conodont genus Panderodus (Llanvirn-Givetian) has been reconstructed from a bedding plane assemblage associated with soft parts from the Waukesha lagerstatte of Wisconsin, together with published clusters and discrete element collections. This modelling enables a redefinition of the apparatus and species concepts within Panderodus, which is now reconstructed as a nonimembrate apparatus, with four subdivisions in the graciliform element category. Architecturally the apparatus falls into three locational domains.

• Read more about The apparatus architecture of Panderodus and its implications for coniform conodont classification

Recent field work in the upper Eocene Krabi Basin (south Thailand) has yielded several dental and postcranial remains of a new genus and species, Egatochoerus jaegeri, of a tayassuid morphologically very close to the upper Eocene North American genus Perchoerus. According to the somewhat more primitive morphology of the Thai species, the family Tayassuidae seems to have originated in South East Asia, and then migrated into the New World as early as late Eocene.

• Read more about An Eocene peccary from Thailand and the biogeographical origins of the artiodactyl family Tayassuidae

The swordfish-like ichthyosaur Eurhinosaurus, primarily from the German Upper Liassic, is generally considered to be monotypic. The authority of the type species, E. longirostris, has usually been given as Jaeger, 1856, but it is shown that Mantell, 1851 is the correct authority. The subject of Mantell's description (BMNH 14566) is from the Upper Liassic of Yorkshire. Recent preparation confirms the presence of an abbreviated mandible, confirming its eurhinosaurian status. E. longirostris (Mantell 1851) is thus unequivocall; the type species of Eurhinosaurus, and BMNH 14566 is the holotype.

• Read more about The taxonomic status of the Upper Liassic ichthyosaur Eurhinosaurus longirostris

Coloborhynchus wadleighi, a new pterosaur from the Paw Paw Formation (upper Albian), Texas, is closely related to an English species Coloborhynchus clavirostris. A dentulous partial snout shows unique tooth arrangement and a dorsal medial crest on the anterior portion of the premaxilla. This is the first tooth-bearing pterodactyloid pterosaur known from North America. The genus Coloborhynchus is assigned to the family Ornithocheiridae.

• Read more about The Early Cretaceous pterodactyloid pterosaur Coloborhynchus from North America

The holotype and only known specimen of Nothosaurus juvenilis from the Hauptmuschelkalk of Germany is redescribed and compared with the type material of all other Nothosaurus species described from the Muschelkalk of central Europe. N. juvenilis proves to be a valid species diagnosed by morphological features and by cranial proportions, as well as by its small overall size.

• Read more about The status of the sauropterygian reptile Nothosaurus juvenilis from the Middle Triassic of Germany