Psephenidae

Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Protostomia
Cladus: Ecdysozoa
Cladus: Panarthropoda
Phylum: Arthropoda
Subphylum: Hexapoda
Classis: Insecta
Cladus: Dicondylia
Subclassis: Pterygota
Cladus: Metapterygota
Infraclassis: Neoptera
Cladus: Eumetabola
Cladus: Endopterygota
Superordo: Coleopterida
Ordo: Coleoptera
Subordo: Polyphaga
Infraordo: Elateriformia
Superfamilia: Byrrhoidea

Familia: Psephenidae
Subfamiliae (5): Afroeubriinae - Eubrianacinae - Eubriinae - Psepheninae - Psephenoidinae

Overview of genera (27)

Acneus – Aethioeubria – Afrobrianax – Afrocephonoides – Afroeubria – Belicinus – Dicranopselaphus – Ectopria – Eubria – Eubrianax – Falsodrupeus – Jaechanax – Jinbrianax – Malacopsephenoides – Mataeopsephus – Micreubrianax – Mubrianax – Neoeubria – Odontanax – Pheneps – Psephenoides – Psephenopalpus – Psephenops – Psephenotarsis – Psephenus – Rhipidiomorphus – Sclerocyphon
Name

Psephenidae Lacordaire, 1854

References

Lee, C.-F.; Jäch, M.A.; Beutel, R.G. 2005: 18.7. Psephenidae Lacordaire, 1854. Pp. 521-533 in: Beutel, R.G. & Leschen, R.A.B. (volume eds.) Coleoptera, Beetles. Volume 1: Morphology and systematics (Archostemata, Adephaga, Myxophaga, Polyphaga partim). In: Kristensen, N.P. & Beutel, R.G. (eds.) Handbook of zoology. A natural history of the phyla of the animal kingdom. Volume IV. Arthropoda: Insecta. Part 38. Berlin, New York: Walter de Gruyter.
Lee, C.-F.; Satô, M.; Shepard, W.D.; Jäch, M.A. 2007: Phylogeny of Psephenidae (Coleoptera: Byrrhoidea) based on larval, pupal and adult characters. Systematic entomology, 32: 502–538. DOI: 10.1111/j.1365-3113.2006.00374.x PDF
Catalogue of Palearctic Coleoptera. Vol. 3 ed. I. Lobl, & A. Smetana, Apollo Books, Stenstrup, Denmark, 2006
ISBN 87-88757-59-5, p.449

Links

Australian Faunal Directory
Psephenidae in SYNOPSIS OF THE DESCRIBED COLEOPTERA OF THE WORLD
Atlas of water pennies (Psephenidae) of Russia
EoL

Vernacular names
čeština: Peřejníkovití
English: water pennies
русский: Волнушки

Water-penny beetles are a family (the Psephenidae) of 272 species (in 35 genera) of aquatic beetles found on all continents except Antarctica, in both tropical and temperate areas.[2] The young, which live in water, resemble tiny pennies. The larvae feed – usually nocturnally – on algae on rock surfaces.[3] 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.[4] 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.[5]

A water-penny larva's shell is oval-shaped to almost circular and is commonly a copper color, which explains 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. Occasionally, they can be found on rocks along the shores of lakes. Attached to the legs are scrapers, which are used to scrape the algae from the surface of a log or rock.

In North America, they are usually found in the Northeast, and occasionally discovered in the Southwest. Some genera in the US:[6]

Psephenus: the Northeast and the west coast (from Oregon to California; usually below 4,000 feet elevation in California).
Eubrianax: California, up to 6,000 feet elevation.
Ectopria: the northeastern and Central U.S.
Acneus: California and Oregon up to 4,000 feet.

As adults, water-pennies become terrestrial. Adults are relatively short lived and eat little to nothing.[3]
Fossil genera

Subfamily Eubrianacinae Jacobson 1913
†Succinumanax Bao et al. 2018 Burmese amber, Myanmar, Cenomanian
†Vetujinbrianax Cai and Huang 2018 Burmese amber, Myanmar, Cenomanian
†Protacnaeus Wickham 1914 Florissant Formation, Colorado, Eocene
†Psephenella Martins-Neto 1998 Tremembé Formation, Brazil, Oligocene

References

"Psephenidae". Integrated Taxonomic Information System.
Beutel, Rolf G. & Leschen, Richard (2005). Morphology and Systematics. Vol. 1. Walter de Gruyter. p. 521. ISBN 978-3-11-090455-0.
Evans, Arthur V. (2014). Beetles of Eastern North America. Princeton University Press. p. 203. ISBN 978-1-4008-5182-9.
EPA: The pollution sensitivity categories for benthic macroinvertebrates: sensitive, somewhat-sensitive, and tolerant. Water-pennies belong to the sensitive category.
Arnett, Ross H. & Thomas, Michael C. (2002). American Beetles: Polyphaga: Scarabaeoidea through Curculionoidea, Volume 2. Pages 133-134.
Usinger, Robert, L., 1956, Aquatic Insects of California, p. 365.