Chilean bivalves: Knowns and unknowns

GÜLLER M. Y D. G. ZELAYA

México DF

Congreso; Mollusca 2014: el Encuentro de las Americas. XIII RENAMAC, IX CAMA, LXXX AMS y XLVII WSM; 2014

Facultad de Ciencias, Universidad Nacional Autónoma de México

The Chilean territory extends for ca. 4.270 km, from 18º24'S (Arica) to 55º56'S (Cape Horn), showing a remarkably narrow, steep continental shelf. Its coast can be roughly divided around 42ºS in a more regular northern area, and a highly intricate southern one, the latter comprising numerous fjords, canals and islets. This change in the coastal physiognomy, associated with changes in physical conditions and faunal associations, is usually considered the boundary between the Magellan and Perú Chilean Provinces. However, a transitional zone between 30° and 42°S has also been suggested by some authors. A revision of extant bibliography reveals a total of 179 valid species of bivalves mentioned over the last two centuries of malacological studies in Chilean waters. But how was the study effort over time? Is at present taxonomic knowledge good enough to allow unequivocal identifications? Are all size ranges equally studied? How many of these species are actually living in the continental shelf? How well do bivalves fit with the two currently recognised biogeographic scenaria? Addressing these questions is the aim of this presentation. For that, a combined study considering all published records, and additional material from several museum collections and personal samplings, is performed. The area south of 42°S is particularly taken as an example of macro and microscale of analysis.