The original description of Tegula ignota was based on three shells found on the coast of Totoralillo Sur, northern Chile. Until now, there are no reports of living specimens of the species. The present study redescribes this snail based on shell, radula, epipodium and mantle characteristics observed in living specimens collected from the subtidal zone of La Boca, central Chile. Additionally, we extend the distribution of T. ignota more than 700 km to the south-eastern Pacific with additional material. Molecular analyses based on the 16S ribosomal DNA mitochondrial gene show that T. ignota is most closely related to Tegula atra than other Chilean species of Tegula. Voucher specimens of T. ignota were deposited in the Museo Nacional de Historia Natural de Chile.

The effect of short-term (5 days) exposure to CO2-acidified seawater (year 2100 predicted values, ocean pH = 7.6) on key aspects of the function of the intertidal common limpet Patella vulgata (Gastropoda: Patellidae) was investigated. Changes in extracellular acid–base balance were almost completely compensated by an increase in bicarbonate ions. A concomitant increase in haemolymph Ca2+ and visible shell dissolution implicated passive shell dissolution as the bicarbonate source. Analysis of the radula using SEM revealed that individuals from the hypercapnic treatment showed an increase in the number of damaged teeth and the extent to which such teeth were damaged compared with controls. As radula teeth are composed mainly of chitin, acid dissolution seems unlikely, and so the proximate cause of damage is unknown. There was no hypercapnia-related change in metabolism (O2 uptake) or feeding rate, also discounting the possibility that teeth damage was a result of a CO2-related increase in grazing. We conclude that although the limpet appears to have the physiological capacity to maintain its extracellular acid–base balance, metabolism and feeding rate over a 5 days exposure to acidified seawater, radular damage somehow incurred during this time could still compromise feeding in the longer term, in turn decreasing the top-down ecosystem control that P. vulgata exerts over rocky shore environments.

Specimens of Conus jaspideus Gmelin, 1791 collected along the Brazilian coast were dissected for morphological studies of the soft parts and radula, in a recharacterization of the species. Two specimens collected in the State of Bahia, proved to be imposex. Specimens in an aquarium were photographed during the process of predation. Herein, for the first time, the atrophied penis of an imposex specimen of C. jaspideus is illustrated, as well as the feeding process, contributing to the knowledge of the family.