Siliquariid Tenagodus (synonym: Siliquaria) snails are obligatory sponge commensals, with uncoiling and laterally slitted shells embedded inside Demospongiae hosts, and shell apertures facing the outside allowing for respiratory and gill-filter-feeding activities. Live-collected animals observed in situ within hosts provide the first detailed functional morphological study of the group, and form the basis for systematic revision of the western Atlantic members of type genus Tenagodus (Siliquariidae, synonym: Tenagodidae). Three species are recognized. Overall anatomical features of wide-ranging Atlantic T. modestus (Dall, 1881) and T. squamatus (de Blainville, 1827) [ = T. anguillae Morch, 18611 are similar to those previously described for New Zealand... |