Archive
Novel ultrastructure in water-conducting cells of the Lower Devonian plant Sennicaulis hippocrepiformis
A description of the ultrastructure of the water-conducting cells in Sennicaulis hippocrepiformis Edwards (1981), an early land plant of uncertain affinity, is based on pyrite and limonite permineralizations from two Lower Devonian localities in Dyfed and Powys, Wales. The ultrastructure of the two-layered cell wall is unique among land plants, although a simple large helical thickening suggests affinity with the Tracheophyta. The lumen of each cell is lined with a thin microporate layer that overlies the bulk of the wall, including the simple helical thickening, which has a spongy texture.
The Pangaea dicynodont Rechnisaurus and the comparative biostratigraphy of Triassic dicynodont faunas
A dicynodont from the Triassic Manda Beds of East Africa is found to belong to the kannemeyeriid genus Rechnisaurus, first described from India, with which the genus Shaanbeikannemeyeria from China and Mongolia is congeneric. The divergent skull modifications of the Families Lystrosauridae and Kannemeyeriidae from the primitive Permian dicynodont skull morphology are explained in functional terms, both being adaptations to increase the length of the jaw adductor muscles.
Belemnites from the Coniacian to Lower Campanian chalks of Norfolk and southern England
Coniacian to Lower Campanian belemnite faunas from the chalks of Norfolk and southern England are described, using univariate and bivariate biometric analyses. The faunas include 13 species, subspecies and groups, referred to the following genera: Actinocamax Miller, Gonioteuthis Bayle, Belemnellocamax Naidin, and Belemnitella d'Orbigny. Two taxa, 'Actinocamax' lundgreni Stolley and Belemnitella p. propinqua (Moberg) of the Belemnitella lineage, are new for England. The nominate subspecies of Actinocamax verus Miller and two other subspecies are discussed.
Mosasaurs from the Upper Cretaceous of Niger
Fragmentary remains from the Dukamaje Formation (' Mosasaurus Shales'), Upper Maastrichtian, S.W. Niger, reveal a diverse mosasaur fauna of at least six genera - Goronyosaurus, Igdamanosaurus nov. gen., Angolasaurus, Halisaurus, Plioplatecarpus, Mosasaurus, and possibly Platecarpus. This represents an astonishingly high number of mosasaur genera from a single horizon, equalling that of the most prolific mosasaur beds of the world, the Niobrara Formation of Kansas, U.S.A. and the Craie Phosphatee de Ciply, Belgium. Plioplatecarpus represents the first documentation in Africa of this genus.
Isolated graptolites from the Llandovery of Kallholen, Sweden
A graptolite fauna of Monograptus argenteus Biozone age (Aeronian = Middle Llandovery), chemically isolated from limestone nodules formerly thought to be of M. turriculatus Biozone age (Telychian = Upper Llandovery), is described. The total fauna comprises Metadimacograptus hughesi (Nicholson), Glyptograptus aff. incertus Rickards, G.
A new marsupiate cidaroid echinoid from the Maastrichtian of Antarctica
Almucidaris durhami is a new genus and species of cidaroid echinoid from the Maastrichtian (Late Cretaceous) of Seymour Island, Antarctic Peninsula. The species is unique in that the genital plates of the female are expanded and hollowed to form marsupia. The incidence of brooding in invertebrates, including echinoderms, increases with latitude and apparent stress; stressful conditions might have contributed to the evolution of A. durhami.
A new species of machaeridian from the Silurian of Podolia, USSR, with a review of the Turrilepadidae
Machaeridians are enigmatic marine fossils, known from rocks of Ordovician to Carboniferous age. Turrilepas modzalevskae sp. nov., from Podolia, Ukraine, USSR, is only the second turrilepadid machaeridian species to be represented by an articulated assemblage. It provides unequivocal evidence for the presence of minute marginal spines, and demonstrates the relationship between these spines and the ornament of the outer sclerite surface.
Silurian cryptospores and miospores from the type Wenlock area, Shropshire, England
The earliest occurrence of sculptured hilate cryptospores and miospores is near the base of the cf. protophanus-verrucatus Sporomorph Zone, now more accurately located within the lundgreni Graptolite Biozone in the type Wenlock area. Palynofacies studies indicate that this event is unrelated to changes in the depositional environment. All the Sheinwoodian sporomorphs are laevigate (six species) and have either a crassitate or patinate structure.
Fishes and amphibians from the Late Permian Pedra de Fogo Formation of northern Brazil
The vertebrate fauna of the Pedra de Fogo Formation of northern Brazil includes a palaeonisciform fish Brazilichthys macrognathus gen. et sp. nov., which is placed in a new family, the Brazilichthyidae. Other fishes include fragments of ctenacanth and xenacanth sharks, edestid holocephalians, and dipnoans. Tetrapods include the archegosaurid amphibian Prionosuchus plummeri, which is compared with other archegosaurs. Its extremely long narrow snout suggests that the Pedra de Fogo Formation is of Late Permian age, rather than Early Permian.