Bioerosion on the small scale – examples from the tropical and subtropical littoral

The purpose of this paper is to provide a practical guide assisting field workers in identification and interpretation of bioerosional textures created in limestone and other substrates by intertidal organisms. We provide examples of living, dead, and subfossil bioerosional agents and their corresponding traces. The discussion follows taxonomic order of bioerosional agents, rather than morphologic classification of their effects on the rock substrate. Traces left by sponges, molluscs (chiton Acanthopleura, limpets and various gastropods, bivalves Lithophaga and Tridacna, wood-boring bivalves), worms, echinoid Echinometra, and other taxa are illustrated. Features created by a distinct group of organisms but exhibiting excellent, average, and poor levels of preservation are displayed alongside each other to help identification under suboptimal conditions. We also show composite textures resulting from successive or coeval overlapping traces, and offer examples of pseudo-bioerosional features reminiscent of organism traces but created by physical processes.