The Global Ordovician Biodiversification Event (GOBE) was undoubtedly one of the most significant evolutionary events in the history of the marine biosphere. A continuous increase in ichnodiversity occurs through the Ordovician in both shallow- and deep-marine environments. The earlier view that early Paleozoic deep-marine ichnofaunas are of low alpha diversity has been challenged by discoveries of moderately diverse associations. Interestingly, however, the increase in global ichnodiversity through the Ordovician is not paralleled by an increase in ichnodisparity of bioturbation structures. In fact, whereas global ichnodiversity in the Ordovician almost doubled Cambrian levels, Ordovician ichnodisparity of bioturbation structures is roughly similar to that resulting from the Cambrian explosion. Macroboring organisms also display significant evolutionary innovation and diversification in shallow-water hardgrounds and other carbonate substrates, resulting in the Ordovician Bioerosion Revolution. Along with this macroboring ichnodiversity and ichnodisparity increase is a significant rise in the rate of bioerosion in carbonate substrates. Ichnofaunal changes in lower-shoreface and offshore siliciclastic deposits through the Ordovician reveal faunal turnovers resulting from the evolutionary radiation. Lower Ordovician deposits tend to be dominated by abundant trilobite-produced trace fossils. Middle to Upper Ordovician shallow-marine ichnofaunas tend to show more varied behavioral patterns and trilobite trace fossils are rarely the dominant components. During the early Paleozoic, the tiering structure of ichnofaunas became more complex, as a result of both the addition of deeper tiers and of a wider variety of biogenic structures in previously occupied tiers. Infaunalization by deposit feeders in offshore siliciclastic environments was most likely diachronous, with the establishment of a mid-tier infauna first in Laurentia and Baltica, and only subsequently in Gondwana.

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The Great Ordovician Biodiversification Event

Ichnology is the study of traces created in the substrate by living organisms. This is the first book to systematically cover basic concepts and applications in both paleobiology and sedimentology, bridging the gap between the two main facets of the field. It emphasizes the importance of understanding ecologic controls on benthic fauna distribution and the role of burrowing organisms in changing their environments. A detailed analysis of the ichnology of a range of depositional environments is presented using examples from the Precambrian to the recent, and the use of trace fossils in facies analysis and sequence stratigraphy is discussed. The potential for biogenic structures to provide valuable information and solve problems in a wide range of fields is also highlighted. An invaluable resource for researchers and graduate students in paleontology, sedimentology and sequence stratigraphy, this book will also be of interest to industry professionals working in petroleum geoscience.

Ichnology: Organism-Substrate Interactions in Space and Time

https://www.cell.com/current-biology/pdf/S0960-9822(13)00029-8.pdf

Molecular timetrees reveal a Cambrian colonization of land and a new scenario for ecdysozoan evolution.

https://decapoda.nhm.org/pdfs/10268/10268.pdf

Model-based multi-locus estimation of decapod phylogeny and divergence times.

Phylogeny of Decapoda using two nuclear protein-coding genes: origin and evolution of the Reptantia.

A reexamination of all available palaeopalaemonid specimens, of the genus Palaeopa- laemon, and material of Bellocaris newfoundlandensis Fong, 1972, is presented. The four described species of Palaeopalaemon are synonymized as one, P. newberryi Whitfield, 1880. A detailed study of the anatomy leads to the conclusion that P. newberryi is the earliest recognized decapod eucarid crustacean with characters of both the glypheoidean palinurans and astacideans. Bellocaris is not a paleopalaemonid but a pygocephalomorph mysidacean peracarid, closely related to Pygocephalus.

M. J. Copeland

Papers

The Late Devonian Palaeopalaemonidae and the earliest decapod crustaceans

A new species of erymid lobster from Lower Jurassic strata (Sinemurian/Pliensbachian), Fernie Formation, southwestern Alberta