Gracilaria chilensis sp.nov. (Rhodophyta, Gigartinales), from Pacific South America

Abstract

Gracilaria chilensis sp.nov. is described and recorded from 30° S to 42° S on the coast of Chile. It closely resembles G. lemaneiformis (Bory) Weber-van Bosse, which also occurs in this region, and has been known by both this name and G. verrucosa (Hudson) Papenfuss. Gracilaria chilensis differs fundamentally from these species in having spermatangia in deep cortical (textorii-type) conceptacles and in having basal absorbing filaments in the cystocarp. Isolates of the species from sites 1300 km apart were cultured through the complete life history and used to verify conspecificity of reproductive plants in field collections. Moreover, the isolates were interfertile, thus demonstrating genetic compatibility of widely disjunct populations and verifying the distribution range. Because of its wide thermal and halotolerance, it is suggested that G. chilensis is distributed farther north and south in the eastern Pacific than present records indicate.