CONICET | Buscador de Institutos y Recursos Humanos

The ichnogenus Psammichnites herein restricted to Psammichnites gigas is based oncomparison of morphology, feeding behaviour, contrast between the burrows and the hostrock and possible producers. The record of siphonal activity as a ?snorkel device? isdiscussed. The diagnosis of the ichnogenus Olivellites now is amended and includes all therecords of Psammichnites in the post-Cambrian. Olivellites is now documented in successionsother than the classical tidal flat deposits facies of the Carboniferous of the USA. We proposethat the producer of Olivellites was an animal with capacity for displacement to differentshallow infaunal levels for different feeding strategies. An interpretation of detritus feedingbehavior with sediment displacement (pasichnia) is favoured here. The producer of Olivelliteswas likely to have been a bivalved mollusc that evolved after the Late Ordovician massextinction. It was euryhaline and lived in a broad bathymetric range, and is recorded intemperate to glacially related successions. The material of Olivellites implexus from westernArgentina is the youngest record of the ichnogegenus from Western Gondwana.