Anadara kagoshimensis (Mollusca: Bivalvia: Arcidae) in the Adriatic Sea: morphological analysis, molecular taxonomy, spatial distribution, and prediction

Morphological analysis, molecular characterization, and a study of the distribution and density of Anadara kagoshimensis (Tokunaga, 1906) specimens collected in the Adriatic Sea were carried out using materials and data collected in the course of 329 bottom trawl hauls conducted in five yearly surveys, from 2010 to 2014. Morphological and molecular analysis allowed clarifying the confused taxonomy of the largest alien ark clam species invading Italian waters and the Mediterranean Sea. Analysis of the distribution and density data demonstrated that, along the Italian coast, A. kagoshimensis is mostly found at depths of 8 to 50 m, with a catch frequency of more than 98% in the hauls involving silty-clay sediment at a depth of 8-30 m. The hotspot map clearly shows a reduction in the distribution area of the species from 2010 to 2012.