There are two UK Noterus species. The genus can be recognised by the broad coxal process on the underside - see ID Aids below.

Length 4 - 5 mm. This species is boat-shaped with the elytra broadest in front of middle. The colour of the elytra is variable but usually mid to dark brown with a slightly lighter pronotum and head. It has a mid-line ridge on the prosternum - see ID Aids below.

Noterus crassicornis is very similar but smaller, 3.5 - 4mm. This species lacks the mid-line ridge on the prosternum. It is less common than N. clavicornis but is found in Leicestershire and Rutland.

It is important to state the size with this species together with a good image of both the upper and lower side of the beetle.

Usually found in ponds.

All year round but most easily recorded in summer.

Both adults and larvae are aquatic, and are commonly found around plants. They have a habit of burrowing through pond and marsh substrate, thus the common name, and are primarily carnivorous, with some scavenging observed.

Widespread and frequent in England and Wales, with fewer records coming from Scotland.

Common in Leicestershire and Rutland.