Cornish Biodiversity Network  -  Supporting Wildlife Recording

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Cornish Red Data (2009)

The descriptive text, below the map, is from the Cornish Red Data Book (2009). The map on this web page depicts the organisms distribution and shows the records made pre-2000 and those made since.

Hydraena pygmaea - A water beetle

Range & Status

Primarily western in distribution from Cornwall to Aberdeenshire, with an outlying record for Sussex. There are very few modern records. Foster (1990) provides a national distribution map.

Regional Distribution

Two records by the author: from the River Kenwyn in 1980 and a small stream at

Trebudannon in 1981. Found in the West Looe River by Adrian Brown in 2004.

Habitat & Ecology

Under stones, in moss and on clods of clay in swift flowing, stony streams and rivers.


Pollution of water courses and river improvement schemes.




I.J. Bennallick, S. Board, C.N. French, P.A. Gainey, C. Neil, R. Parslow, A. Spalding and P.E. Tompsett. eds. 2009. Red Data Book for Cornwall and the Isles of Scilly. 2nd Edition.Croceago Press.

The Cornish Red Data Book Project was led by the Cornwall and Isles of Scilly Federation for Biological Recorders (CISFBR). The full text and species accounts (minus the maps) are available on the CISFBR website.