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Family Psephenidae - Water Penny Beetles

Acneus larva - Acneus Acneus quadrimaculatus Horn - Acneus quadrimaculatus - male Dicranopselaphus variegatus Horn - Dicranopselaphus variegatus Water Penny Beetle - Psephenus herricki Psephenus sp - Psephenus herricki Acneus from Oregon - Acneus Psephenus herricki Dicranopselaphus variegatus
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Coleoptera (Beetles)
Suborder Polyphaga (Water, Rove, Scarab, Long-horned, Leaf and Snout Beetles)
No Taxon (Series Elateriformia)
Superfamily Byrrhoidea (Pill, Water and Toe-winged Beetles)
Family Psephenidae (Water Penny Beetles)
Explanation of Names
Psephenidae Lacordaire 1854
Water penny: larvae are flat, often circular
16 spp. in 6 genera in our area(1), ~300 spp. in 15 genera total(2)
3-7 mm(1)
Adults flattened, usually dark:

Larvae aquatic, distinctive, cling to rocks and found more often than adults:
worldwide, most diverse in E. Asia; Eubrianacinae (represented in our area by Eubrianax) are circumpacific, Psepheninae (represented in our area by Psephenus) are primarily a New World group, and Eubriinae (the rest of our genera) are globally distributed(1)
Larvae on the underside of rocks of submerged wood in fast-flowing water. Adults on rocks and vegetation along streams.
Adults only in summer(1)
Larvae graze on algae; some are detritivorous(1); adults are short-lived
Life Cycle
semivoltine; larvae overwinter, pupate under riparian substrates or in water(1)
Print References
Internet References
Family page (Hammond 2009)
Works Cited
1.American Beetles, Volume II: Polyphaga: Scarabaeoidea through Curculionoidea
Arnett, R.H., Jr., M. C. Thomas, P. E. Skelley and J. H. Frank. (eds.). 2002. CRC Press LLC, Boca Raton, FL.
2.Order Coleoptera Linnaeus, 1758. In: Zhang Z.-Q. (ed.) Animal biodiversity: An outline of higher-level classification...
Ślipiński S.A., Leschen R.A.B., Lawrence J.F. 2011. Zootaxa 3148: 203–208.
3.Water Beetles of South Carolina
Janet Ciegler. 2003. Clemson University.
4.Lawrence J.F., et al. (2000-2005) Elateriformia (Coleoptera): descriptions, illustrations, identification...