All post- Cambrian ichnospecies of Psammichnites Torell, 1870 belong to Olivellites Fenton and Fenton, 1937a

The ichnogenus Psammichnites herein restricted to Psammichnites gigas is based on comparison of morphology, feeding behaviour, contrast between the burrows and the host rock, and possible producers. The record of siphonal activity as a “snorkel device” is discussed. The diagnosis of the ichnogenus Olivellites now is amended and includes all the records of Psammichnites in the post-Cambrian. Olivellites is now documented in successions other than the classical tidal flat deposits facies of the Carboniferous of the USA. We propose that the producer of Olivellites was an animal with capacity for displacement to different shallow infaunal levels for different feeding strategies. An interpretation of detritus feeding behavior with sediment displacement (pasichnia) is favoured here. The producer of Olivellites was likely to have been a bivalved mollusc that evolved after the Late Ordovician mass extinction. It was euryhaline and lived in a broad bathymetric range, and is recorded in temperate to glacially related successions. The material of Olivellites implexus from western Argentina is the youngest record of the ichnogenus from Western Gondwana.