The platycopid signal: a means of detecting kenoxic events using Ostracoda

Abstract. It has been shown that during Jurassic and Cretaceous kenoxic events, while other groups of benthonic Ostracoda severely decline and eventually disappear, the Platycopina tend to survive. The survival of the platycopids is attributed to their being filter feeders who, in dysaerobic conditions manage to obtain sufficient oxygen by virtue of the greater volume of water which they circulate across their respiratory surface in the course of their normal feeding behaviour. The podocopid ostracods, which are predators, scavengers and deposit feeders, are unable to survive the diminished oxygen concentrations which characterise these events. The platycopid genus Cytherella is shown to dominate the oxygen mininmum zone in two different parts of the Atlantic at the present day.