Abstract The shallow marine carbonate deposits of the S. Miguel Formation in the Lusitanian Basin reveal erosional events exposing stiff substrates with abundant Bergaueria hemispherica . The ichnoassociation represented by B. hemispherica , Thalassinoides suevicus , Spongeliomorpha isp., Asterosoma ludwigae and Rhizocorallium commune is dated from lowermost Pliensbachian by the association with ammonites from the jamesoni Biozone, brevispina Subzone. The unlined forms of B. hemispherica include peripheral and bottom burrow concentrations of shell debris, annular-like structures in the burrow margin and paired burrows-to-linear clusters that are comparable with the penetrative burrowing mechanism, anchoring and feeding behaviours of sea anemones. From the ethological point of view, and comparing with modern behaviours of burrowing anemones, the B. hemispherica from the Lusitanian Basin may represent temporary burrowing and relocation of actiniarian anemones. Their comparison with either thenarian or athenarian actiniarians may evidence a preferred surficial feeding strategy on the organic-rich muddy sediments they burrowed.

Abstract Coastal erosion impact on low-lying sandy shorelines represents a worldwide problem, which is particularly felt in various segments of the Portuguese coast where this geomorphological type represents 42% of its total length. Beach nourishment is a viable engineering alternative for shore protection and the assessment of offshore sources of beach-fill material is an essential aspect when implementing this mitigation strategy. The CHIMERA project carried out a multidisciplinary inspection on four segments of the west Portuguese coast to assess their potential as offshore borrow areas for beach nourishment. Altogether, these segments covered an area of c . 35 km 2 , at water depths between 20 and 42 m. They were surveyed using multibeam, sub-bottom profiler, ultra-high resolution multichannel seismics and a set of 126 surface samples and 72 vibrocores (with 3 m long each). To comply with the Portuguese legislation, sand types were assessed by granulometric and chemical analyses for evaluating the quality of sediments in terms of contamination. High-resolution magnetic surveys were conducted to find potential archaeological artefacts. The adopted methodology proved to be adequate to quantify and describe the spatial distribution of useful sediment volumes, supporting the ongoing Integrated Coastal Sediment Strategy for mainland Portugal.