Distribution and ecology of Pisidium chiquitanum (Ituarte, 2001) (Bivalvia, Sphaeriidae) in Central-West from Argentina.).

CIOCCO, NÉSTOR; KOCH E

Congreso; XXXIV Reunión Científica de la Sociedad de Biología de Cuyo; 2018

Sociedad Biología de Cuyo

The first record of genus Pisidium in central-west from Argentina was in 2008 when P.chiquitanum was found on a site fromnorthern Mendoza Province (MP), which greatly enlarged the southern range distribution of this species (central Bolivia to NWArgentina). The first data on distribution of this clam and environmental variables associated with the species from the North tothe South of MP (Southern portion of Cuyo Malacological Province, CMP) were reported three years later. As part ofcomprehensive surveys of CMP, we explored the Northern portion of this malacological region, from South of La Rioja Province(LRP) to South of San Juan Province (SJP). The goal is to provide unedited data on presence and environmental variablesassociated with this clam in North of CMPand to complete the available information about ecology of this clam in all CMP.Twenty-one lentic and moderately lotic sites were sampled between716 and 2731 m a.s.l., from 29º20.72S (Bermejo dam, LRP)to 32º7.04S (Santa Clara, SJP), and from 67º19.478W (Las Tumanas, SJP East) to 69º50.301W (Manantiales, Andeanmountains). At each site biological samples and environmental variables were recorded. The ranges (21 sites in all) ofconductivity (C), water temperature (WT), pH, Depth (D), dissolved oxygen (DO), turbidity (T), current velocity (CV) andvegetation cover (VC) were: 0.241?22.2 mS cm-1; 7.4?32.5 ℃; 7.4?9.1; 1?27 cm; 4?15.8 mg l-1; 0?432.7 NTU; 0?1.7 m sec-1and 0?90%, respectively. P. chiquitanum only was recorded at Vega El Leoncito, a shallow and moderately lotic site with highplant cover located in South of SJP at 2184 m.a.s.l. In this site high clam densities were associated to soft and relatively warmwaters (C mean: 0.24 mS cm-1; WT spring mean: 15.7 ℃) and substratum dominated by very fine sand (mean %: 78.5). On atotal of 94 lentic and lotic sites prospected to date in all CMP from 29º20.72S to 35º39S and 402 to 4000 m a.s.l.,P.chiquitanumwas found in 9 sites between 965 and 2386 m a.s.l.,8 from Mendoza, Tunuyán, Atuel and Llancanelo basins (mostly shallowmargins of streams and brookletswith abundant vegetation cover), and the spring of Vega El Leoncito reported hear. In all,ranges of C, WT, pH, D and very fine sand % where the clamoccurred were 0.18-1.21mS.cm-1, 6.2-25.1oC, 6.84-9.40, 5-50cm BIOCELL 43 (suppl. 4), 2019 ABSTRACTSISSN 0327- 9545 A1 ? A210ISSN 1667-5746 (online version)and 9.4-78.5%, respectively. In central-west of Argentina, P. chiquitanum inhabits mostly shallow, vegetated and slightlyrunning waters from Andean piedmont, and it has a relatively broad range of tolerance to environmental conditions.