Water pennies

Code QC379999

A family of Polyphaga - the large suborder of beetles in which the prothoracic pleuron is entirely concealed and the hind coxae are motile.

Psephenidae are small to medium-size (2.8-8 mm), broadly oval, somewhat flattened beetles. The dorsal surfaces are covered in short, dense setae through which a pattern of light and dark markings can be seen on the elytra. The head is deflexed and only partly visible from above: set within a frontal emargination of the pronotum, and narrowed anteriorly forming a short rostrum. Antennae short, 11-segmented, without a club. Rear margin of the pronotum and front margins of elytra and scutellum finely crenulate and interlocking.

On the underside: Mouthparts usually concealed by a prosternal chin-piece. A prosternal process fits into a metasternal cavity, holding prothorax and hind body together. Transverse suture present on the metasternum.

Psephenidae (Polyphaga, placed in Byrrhoidea by Australian authors, Dryopoidea by American authors) are represented in Australia by around 15 species, all in the genus Sclerocyphon . Larval psephenids are streamlined animals which feed on algae on rocks in exposed positions with high energy flows. The adults are cryptic but have been observed flying above streams on hot days. They occur in eastern Australia, with one species recorded from the George Gill Ranges in central Australia.

Reference:

Lawrence, J.F. and Britton, E.B. (1991) Coleoptera. pp. 543-683. In: CSIRO, Insects of Australia. Volume 2. Melbourne University Press, Carlton, Victoria.