Palaeoenvironmental control on distribution of crinoids in the Bathonian (Middle Jurassic) of England and France

Bulk sampling of a number of different marine and marginal marine lithofacies in the British Bathonian has allowed us to assess the palaeoenvironmental distribution of crinoids for the first time. Although remains are largely fragmentary, many species have been identified by comparison with articulated specimens from elsewhere, whilst the large and unbiased sample sizes allowed assessment of relative proportions of different taxa. Results indicate that distribution of crinoids well corresponds to particular facies. Ossicles of Chariocrinus and Balanocrinus dominate in deeper-water and lower-energy facies,with the former extending further into shallower-water facies than the latter. Isocrinus dominates in shallower water carbonate facies, accompanied by rarer comatulids, and was also present in the more marine parts of lagoons. Pentacrinites remains are abundant in very high-energy oolite shoal lithofacies. The presence of millericrinids within one, partly allochthonous lithofacies suggests the presence of an otherwise unknown hard substrate from which they have been transported. These results are compared to crinoid assemblages from other Mesozoic localities, and it is evident that the same morphological ad-aptations are present within crinoids from similar lithofacies throughout the Jurassic and Early Cretaceous

Traces of cassid snails predation upon the echinoids from the Middle Miocene of Poland: Comments on Ceranka and Zlotnik [2003]

Small round holes in the tests of fossil echinoids present problems of interpretation, the most obvious questions being who did it and why? Both have been the cause of considerable conjecture by ichnologists and echinoderm palaeontologists. “Drill holes” described from the Miocene of Poland in the echinoid Echinocyamus linearis Capeder are classified within the ichnospecies Oichnus simplex Bromley. Contrary to the original analysis, the possibility remains that some of these holes were the result of eulimid parasitism rather than predation by juvenile cassids. If other, larger echinoids in the fauna suffered predation by adult cassids, then the available samples are probably too small for it to be recognised