An ichthyosaur carcass-fall community from the Posidonia Shale (Toarcian) of Germany

The possibility that large marine reptiles and other Mesozoic vertebrates produced nekton-fall communities similar to those of modern cetaceans is presently receiving increased attention in the literature. The author describes a rare ichthyosaur carcass-fall community from the Posidonia Shale (lower Toarcian) of Germany, which provides insights into the role played by large marine vertebrates in determining regional benthic ecology during this period. It is demonstrated here that, while more important than previously thought, there is little evidence to suggest that ichthyosaur carcasses played a substantial role in structuring the benthic ecology of the European Toarcian epeiric sea. In general, within the shallow waters of the Posidonia Shale, conditions conducive to the creation of carcass-fall communities were rare, and when present, resulted in localized magnification of background taxa and higher local biodiversity, rather than a unique community of epibiont organisms. The community which developed is ecologically similar to modern whale-fall communities, but differs in important ways, particularly with regard to the presence/absence of the chemosynthetic faunas which are most intensively described in the literature.