An analysis of museum specimens reveals that reports of the chelonophilic barnacle Cylindrolepas darwiniana are misidentifications of the similar turtle barnacle Platylepas decorata. As a result, contemporary collections from loggerhead and hawksbill sea turtles represent the first report of this turtle barnacle since its description nearly a century ago. Novel morphological characters that clearly distinguish C. darwiniana from other turtle barnacles have been ascertained from the recent specimens and are reported.