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The ancestry of the vertebrates
The stratigraphy of the Actinocamax plenus Subzone (Turonian) in the Anglo-Paris Basin
In the central parts of the Anglo-Paris Basin the Actinocamax plenus Subzone of the Inoceramus labiatus Zone conforms more or less to a standard succession of eight beds, numbered 1 to 8 in ascendingExpand
The Ordovician Fossil Lagynocystis pyramidalis (Barrande) and the Ancestry of Amphioxus
It follows, since Lagynocystis had a calcite skeleton, that such a skeleton has been lost at least twice in the evolution of the chordates, and that the latest common ancestor of vertebrates and amphioxus would be a primitive mitrate. Expand
The Early Phylogeny of Chordates and Echinoderms and the Origin of Chordate Left–Right Asymmetry and Bilateral Symmetry
The history of the echinoderm stem group is reconstructed and left–right asymmetry in Dexiothetica results mainly from dexiothetism—an episode in their ancestry when an animal resembling the Recent pterobranch Cephalodiscus lay right-side-downwards on the sea floor. Expand
Findings from the Lower Devonian Hunsruck Slate clearly demonstrate that the mitrate appendage was used in locomotion and that this movement took place appendage-first, and argues against a phylogenetic position in the echinoderm crown-group. Expand
Paired gill slits in a fossil with a calcite skeleton
Using computer X-ray microtomography, the anatomy of Jaekelocarpus is described in greater detail than formerly possible, evidence of paired gill slits internally is revealed and its phylogenetic position within the deuterostomes is suggested. Expand
The English Silurian fossil Placocystites forbesianus and the ancestry of the vertebrates
Placocystites forbesianus de Koninck, from the Silurian Dudley Limestone, is here interpreted as a primitive chordate with a calcite skeleton of echinoderm type, which agrees with earlier papers by the senior author and disagrees with the work of Ubaghs. Expand
Two types of bilateral symmetry in the Metazoa: chordate and bilaterian.
Evidence derived from certain bizarre Palaeozoic marine fossils gives a detailed history of the early evolution of echinoderms and chordates and shows how the new bilateral symmetry was gradually acquired in chordates. Expand