Archive

Detailed examination of isolated thecal plates belonging to three discocystinid edrioasteroids, Spiraclavus nacoensis Sumrall, Hypsiclavus kinsleyi Sumrall, and Giganticlavus bennisoni Sumrall and Bowsher, reveals striking similarity in morphology among these species. Stereom observed in the ambulacral floor plates indicates that ligamentous connective tissue opened the ambulacral cover plates and muscle tissue closed them. The ambulacral floor plates are interpreted as rigid supports for the oral surface with the interambulacral areas acting as flexible integuments of plates.

• Read more about Morphology and biomechanical implications of isolated discocystinid plates (Edrioasteroidea, Echinodermata) from the Carboniferous of North America

A low diversity fossil assemblage dominated by Mongolitubulus spines, from the Early Cambrian Geres Member of the Shabakhty Formation at Koksu, Malyi Karatau, Kazakhstan, enables identification of its sclerite variability within the scleritome. No other sclerotised structures could be matched with the spines, indicating that these were the only sclerotised part of the body and were periodically shed. The prominent spines of Mongolitubulus have a scale-like external ornamentation and fibrous internal structure. Possibly they armed the body of a lobopodian similar to Xenusion.

• Read more about Early Cambrian lobopodian sclerites and associated fossils from Kazakhstan

The juvenile shell of living discinid brachiopods is composed of valvular mosaics of rhombic, micrometric-sized siliceous tablets. The tablets are shed in adult growth stages leaving shallow imprints on the primary layer of the organophosphatic mature shell, which occur on an upper Silurian discinoid. Imprints also indent the first-formed shells of over 100 lingulate genera, including all acrotretides and Paterula. No micrometric bodies that could have made these imprints are known, but their structure and composition can be inferred from imprint morphology.

• Read more about Microscopic imprints on the juvenile shells of Palaeozoic linguliform brachiopods

Attention is drawn to Nielsen's radical body plan concept, here named the 'brachiopod fold hypothesis', under which brachiopods and phoronids are recognized to be transversely folded across the ontogenetic anterior-posterior axis so that, to make useful comparisons with other phyla, these organisms must be conceptually unfolded. Under the hypothesis brachiopod brachial and pedicle shell valves are respectively 'anterior' and 'posterior' rather than 'dorsal' and 'ventral' as traditionally described.

• Read more about The brachiopod fold: a neglected body plan hypothesis

An Early Cretaceous (Hauterivian) hermit crab perfectly preserved within an ammonite is described. Palaeontologists have focused too much on the wrong class of molluscs in their attempt to analyse the evolution of the pagurids. The shift of mollusc habitation during the Cretaceous, from ammonites to gastropods, affected the morphology of the aperture-blocking hermit-crab claws.

• Read more about The oldest in situ hermit crab from the Lower Cretaceous of Speeton, UK

Reinvestigation of Nystroemia pectiniformis Halle from the Upper Shihhotze Formation of Shanxi Province, China, has led to the identification of new and important features of this enigmatic Late Permian seed plant, permitting its typification and diagnosis. After reassembling several of the previously studied specimens to form a single articulated branching system comprising at least four orders of branching, previously unknown features of its branching pattern and morphology have been characterized.

• Read more about Reinvestigation of Nystroemia pectiniformis Halle, an enigmatic seed plant from the Upper Permian of China

The genus Ctenopyge is known mainly from disarticulated sclerites and from rare complete specimens flattened in shales. Hitherto, very few specimens have been found preserved intact and in three dimensions. In a recently discovered fauna, however, in the Peltura minor Subzone in Vastergotland, central Sweden, there occur several species of Ctenopyge, of which many are complete and superbly preserved; moreover they occur at all stages of growth.

• Read more about Structure, ontogeny, and moulting of the olenid trilobite Ctenopyge (Eoctenopyge) angusta Westergård, 1922 from the upper Cambrian of Västergötland, Sweden

A conulariid-like fossil is described for the first time from Upper Vendian (late Neoproterozoic) deposits. Vendoconularia triradiata gen. et sp. nov. is found with other fossils in poorly cemented, siliciclastic deposits of the lower part of the Ust'-Pinega Formation, exposed in the middle reaches of the Onega River, north of the Russian Platform. This fossil assemblage, stratigraphically lowermost in the region, includes Swartpuntia Narbonne, endemic Ventogyrus Ivantsov and Grazhdankin, Calyptrina-like tubular forms, and other new, as yet undescribed, species.

• Read more about Conulariid-like fossil from the Vendian of Russia: a metazoan clade across the Proterozoic/Palaeozoic boundary

Sauropod dinosaurs are poorly represented in the Lower Cretaceous of eastern Asia. Here, we describe a number of isolated sauropod teeth from the Kuwajima Formation (?Berriasian-?Hauterivian) of Shiramine, Japan. The mosaic of shared derived characters and symplesiomorphies displayed by the teeth indicate that they are referable to a basal member of the titanosauriform radiation.

• Read more about Sauropod dinosaurs from the Lower Cretaceous of eastern Asia: taxonomic and biogeographical implications

Four Middle and Upper Cambrian burlingiid trilobites from the Oslo Region, Norway, are described including Burlingia angusta sp. nov. from the Ptychagnostus punctuosus Zone and Schmalenseeia athrotryphe sp. nov. from the lower part of the Lejopyge laevigata Zone. New complete material previously attributed to Schmalenseeia jagoi Whittington is assigned to Burlingia.

• Read more about Burlingiid trilobites from Norway, with a discussion of their affinities and relationships