The Conchological Society of Great Britain and Ireland

Populations of the planorbid Gyraulus acronicus have been surveyed in four rivers in the upper catchment of the River Thames, England. The species appears to be restricted to short sections of each river near their confluences with the Thames. The habitats are characterized by clean, slow-flowing calcareous water and densely vegetated margins. Recent evidence suggests that the species is very restricted in its distribution in England and therefore conservation of G. acronicus should have a high priority in the management programmes for the rivers that support the species.