Water-penny beetle
family of beetles
Water-penny beetles are a family (the Psephenidae) of 273 species (in 35 genera) of aquatic beetles found on all continents except Antarctica, in both tropical and temperate areas. The young, which live in water, resemble tiny pennies. The larvae feed – usually nocturnally – on algae on rock surfaces. The presence of water-penny larvae in a stream can be used as a test for the quality of the water, as they are pollution-sensitive. They cannot live in habitats where rocks acquire a thick layer of algae, fungi, or inorganic sediment. Therefore, their presence along with other diverse phyla signifies good-quality water. They are around 6 to 10 millimeters in length.
A water-penny larva's shell is oval-shaped to almost circular and is commonly a copper color, hence the name, 'water-penny'. Water-pennies obtain oxygen through their membrane and through feathery gills located at the base of the abdomen. They are typically found in riffles in streams with a moderate to fast current, clinging to the underside of logs or rocks.
“Water-penny beetle” enters the record as family of beetles. Crown Archives preserves that source wording while asking what Water-penny, beetle and family can confirm, complicate or overturn.
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This entry incorporates text from “Water-penny beetle” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.