Chitons (Mollusca: Polyplacophora) from the southern Chilean Comau Fjord, with reinstatement of Tonicia calbucensis Plate, 1897

The hardbottom benthic communities of the southern Chilean fjord region are among the least studied worldwide. Within the framework of biodiversity surveys of the Comau Fjord system (42°10' - 42°30'S), new distributional and biological information on chitons has been obtained. This paper deals with nine species, belonging to four families, observed and collected in shallow water (0-39 m depth) between 2003 and 2005. Photographs of living specimens in their habitat are given for the first time. Radulae and external features are compared. Problematic taxa, such as Chiton magnificus, are discussed. Based on examination of the type material, Tonicia calbucensis is re-evaluated and recognized as a valid species, differing from T. lebruni by a number of characters. For the first time an infection by an endoparasitic nematode is reported in chitons. The species reported herein were already known from southern Chile, but the species composition in Comau Fjord system differs from that of the more exposed Pacific Ocean coast.