Abstract

"The Strait of Magellan is a complex natural channel that connects the Pacific and Atlantic Oceans. Due to the weather and oceanographic characteristics of this zone, scientists have been interested in its biota, generating numerous expeditions and studies focused to the marine ecosystems. However, major research has been oriented towards sublitoral environments, creating a lack in the knowledge of numerous intertidal places. The Buque Quemado Beach, located on the oriental end of the Strait of Magellan, corresponds to an area dominated by soft substrata, and it has not yet been characterized from the malacological point of view. In April 2008, exhaustive sampling using a transect perpendicular to the coast line, from the upper intertidal to the lower intertidal was carried out, where all molluscs were collected, which were then fixed, identified and photographed; carrying out observations on the taxonomy, ecology, distribution and biogeography of all species. Twelve species were identified (2 Polyplacophora, 9 Gastropoda and 1 Bivalvia) from the 218 examined specimens, of which 69% corresponded the bivalve Mytilus edulis chilensis. Fifty eight percent of the species exhibited a Magellan distribution and the 42% remaining demonstrated a wide distribution embracing two or more biogeographic provinces. The low number of obtained species could respond mainly to physical factors of the beach, considering that soft substrates act as an important spatial factor, shrinking intertidal diversity."