First comparative assessment of the reproductive cycle of three species of Chiton on a temperate rocky shore of the southeastern Pacific

The present study provides the first assessment of the reproductive cycle of three common and widespread species of the genus Chiton, sympatric in rocky shores of Coquimbo, northern Chile (~30°S): C. granosus, C. cumingsii, and C. magnificus. From specimens seasonally sampled during a 2-year period, a histological study was performed in order to describe the gonad structure and stages of gonadal development for each species. The morphological structure of the gonad was similar in the three species, with sexual cells developing from the gonad wall towards its center. The three species were gonochoric and iteroparous, with asynchronous gamete maturation at population level; in all seasons, sexual maturity was evident in small to large individuals of each species (≥25 mm in total length for C. cumingsii and C. granosus, and ≥47 mm for C. magnificus).