Due to the fact that Anomalocardia brasiliana occurs
predominantly in the first 10 cm of the sediment column
(Silva and Silveira, 1992; Narchi, 1972; Schaeffer-Novelli,
1980), we used a circular collector with an area of
0.0192 m2 buried approximately 10 cm into the substrate
to collect the animals. The collected specimens were
washed, and subsequently stored in labelled plastic vials
and frozen for further analysis. The sediment was collected
using a galvanised iron collector with a diameter of
5.6 cm and a length of 10 cm. The collected material was
analysed at the Laboratory of Limnology of the Brazilian
Federal University at Mossoró-RN (Universidade Federal
Rural do Semi-Árido, UFERSA). Shell length of all
living individuals of A. brasiliana was determined using
a 0.05 mm precision caliper. The sediment was collected
using a galvanised iron collector with a diameter of
5.6 cm and a length of 10 cm. For the analysis, the samples
were oven-dried at 60 °C until constant weight. Sub-