There are e types of skeletal abnormalities observed on individuals caught in Sado estuary: dentary, vertebrae and hypural plates, with the latter the most common. These deformaties were more frequent in the industrialized bank of the estuary allowing the relationship between pollution and observed teratology; thus, the species may be considered a pollution indicator species (Ref. 45053). Found in Tagus estuary (Ref. 51031).