The distribution of all known Cambrian echinoderm taxa, encompassing both articulated specimens and taxonomically diagnostic isolated ossicles, is documented for the first time. The database described by 2011 comprises 188 species recorded from 65 formations from around the world. Formations that have yielded articulated echinoderms are unequally distributed in space and time. Only Laurentia and West Gondwana provide reasonably complete records at the resolution of Stage. The review of the biogeographical distributions of the eight major echinoderm clades shows that faunas from Laurentia and Northeast Gondwana (China and Korea) are distinct from those of West Gondwana and Southeast Gondwana (Australia); other regions are too poorly sampled to make firm palaeobiogeographical statements. Analysis of alpha diversity (species per formation) shows that diversity rose initially to Cambrian Stage 5, declined into Guzhangian and Paibian before returning to Stage 5 levels by the end of the Cambrian. This pattern is replicated in Laurentia and West Gondwana. We show that taxonomically diagnostic ossicles found in isolation typically occur significantly earlier than the first articulated specimens of the same taxa and provide important information on the first occurrence and palaeobiogeographical distribution of key taxa, and of the phylum as a whole.Supplementary material:Articulated Cambrian echinoderms and Isolated plates of Cambrian echinoderms are provided at:http://www.geolsoc.org.uk/SUP18668
Central Europe consists of a complex mosaic of more or less independent terranes with varying tectonometamorphic histories, usually also of different lithological compositions and protolith, and thus it is reasonable to suppose that the majority of these blocks have experienced somewhat different palaeogeographical evolution. The present terrane juxtaposition has been interpreted in general as a result of the Variscan collision of peri-Gondwanan and peri-Baltic derived terranes, with Gondwana on one side and Baltica and/or Laurentia on the other side. However, reconstruction of the pre-Variscan development and mutual palaeogeographical relationships remains a major challenge of interpretation.
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