Distribution and environmental parameters related to the presence of the clam Pisidium chiquitanum Ituarte, 2001 (Bivalvia, Sphaeriidae) in Mendoza Province, Argentina.

CIOCCO, N.F.; DE FRANCESCO, C. ; MACCHI, P.; BUONFIGLI, J.

Mendoza Argentina

Congreso; XXVIII Reunión Científica de la Sociedad de Biología de Cuyo; 2010

Sociedada Biológica de Cuyo

Nineteen species of the genus Pisidium have been described in southern South America.  None was recorded in Cuyo region until 2008, when P.chiquitanum was found on a site from northern Mendoza Province (MP), which greatly enlarged the southern range of the species distribution (central Bolivia to NW Argentina) and was the first record of the genus in central-west Argentina. In prospecting water bodies from north to south of MP, the species was detected at several new sites. The goal is to provide unedited data on distribution of this clam in MP and the first records of environmental variables associated with the species. We explored presence-absence of the clam in 73 benthos samples from lentic and lotic sites between 402 and 4000 m a.s.l. (meters above sea level) from all MP basins, and recorded conductivity (C), water temperature (WT), pH, depth (D), and sediment organic content (%; OC) and grain size for each locality. The species was found at 8 sites (965-2386 m a.s.l.) from Mendoza, Tunuyán, Atuel and Llancanelo basins (32o22´ to 35o39´S), mostly streams and brooklets. Ranges of C, WT, pH, D, OC and very fine sand % where the clam occurred were 0.18-1.21mS.cm-1, 6.2-25.1oC, 6.84-9.40, 5-50cm, 1.7-11.7% and 9.4-63.4%, respectively. Our data enhance P. chiquitanum’s southern distribution and suggest that it mostly inhabits shallow, slightly running waters and that it has a relatively broad range of tolerance to environmental conditions.