Taxonomic revision of the Onchidiidae (Mollusca: Gastropoda: Pulmonata) from the Tropical Eastern Pacific

The diversity of air-breathing onchidiid marine slugs is revised for the Tropical Eastern Pacific, or TEP, which extends from the northernmost end of the Gulf of California to the Gulf of Guayaquil, Peru, including nearby oceanic islands such as the Galapagos. Six nominal species exist in the literature for the TEP. Four names are regarded as valid: Onchidella binneyi Stearns, 1894, from Ecuador to the Gulf of California; Onchidella steindachneri (Semper, 1885) and Hoffmannola lesliei (Stearns, 1892), endemic to the Galapagos; Hoffmannola hansi Marcus and Marcus, 1967, endemic to the Gulf of California. Onchidella hildae Hoffmann, 1928 is regarded as a new synonym. Onchidella carpenteri (Binney, 1861) is regarded as a nomen dubium. Our data confirm previous results indicating that the highest rate of endemism in the TEP is found in the Galapagos. The anatomy of valid species is described and compared to other onchidiids.