Colonization plasticity of the boring bivalve Lithophaga aristata (Dillwyn, 1817) on the Southeastern Brazilian coast: considerations on its invasiveness potential

Lithophaga aristata is a boring bivalve native to the Caribbean Sea, first recorded in 2005 as an introduced species on the Southeastern Brazilian coast. The geographic distribution and density of L. aristata and of its native congeneric L. bisulcata were assessed in four areas of Brazil (24 sites), additionally considering their relationship with types of substrate, depth and wave exposure. This study records the first occurrence of L. aristata in the Sepetiba Bay and also reports the species at five new localities in the Arraial do Cabo Bay. Lithophaga aristata is established in the four surveyed regions. At intertidal habitats, the exotic species only colonizes the infralittoral fringe but its density was not related to wave action. At subtidal habitats, the species colonizes natural and artificial substrates, from shallow (0.5m) to deep (5.0-7.0m) zones but no relationship between density and these evaluated factors was detected. Broad geographical and ecological distributions and higher densities of this introduced species in relation to its native congeneric are suggested as contrary to Darwin's naturalization hypothesis and instead indicate a high invasiveness potential.