A water beetle is a generalized name for any beetle that is adapted to living in water at any point in its life cycle. Most water beetles can only live in fresh water, with a few marine species that live in the intertidal zone or littoral zone. There are approximately 2000 species of true water beetles native to lands throughout the world.
Polyphaga is the largest and most diverse suborder of beetles. It comprises 144 families in 16 superfamilies, and displays an enormous variety of specialization and adaptation, with over 350,000 described species, or approximately 90% of the beetle species so far discovered.
The Elateroidea are a large superfamily of beetles. It contains the familiar click beetles, fireflies, and soldier beetles and their relatives. It consists of about 25,000 species.
The Lymexylidae, also known as ship-timber beetles, are a family of wood-boring beetles. Lymexylidae belong to the suborder Polyphaga and are the sole member of the superfamily Lymexyloidea.
Scirtoidea is a superfamily of beetles. It is traditionally considered to consist of four families: Clambidae, Decliniidae, Eucinetidae and Scirtidae. However, genetic studies have suggested that Clambidae and Eucinetidae belong to a separate superfamily Clamboidea, which also includes Derodontidae. Scirtoidea and Clamboidea are the two earliest diverging lineages of living polyphagans.
Histeroidea is a superfamily of beetles in the infraorder Staphyliniformia.
Nosodendridae is a family of beetles, with only 67 species in three extant genera, which are found worldwide. Nosodendron, the largest genus, is found in forests and attracted to yeast generated slime on the wounds of trees, and likely consumes fermented substances as well as fungi and microorganisms. Several additional genera and species are known from the fossil record. Nosodendridae is considered to be an isolated lineage within Polyphaga, being the sister group to the clade containing Staphyliniformia, Bostrichoidea and Cucujiformia.
Alexiidae is a family of beetles. It contains a single genus, Sphaerosoma, formerly included within the family Cerylonidae, with around 50 species which are native to the western Palearctic. Species of Sphaerosoma are very small, around 1 to 2 mm in length rounded beetles with clubbed antennae. They are fungivores, having been observed feeding on mushrooms, and have been also been found in leaf litter and on decaying bark.
Phloeostichidae is a family of beetles in the superfamily Cucujoidea. They are typically found under the bark of dead trees. Larvae have been found to consume plant tissue and some fungus, while the adults appear to be exclusively fungivores. The family contains four extant genera, Phloeostichus is native to the Palearctic, Rhopalobrachium is native to central-southern South America and eastern Australia, Hymaea is native to southeastern Australia, and Bunyastichus is found in Tasmania.
The Brachypsectridae are a family of beetles commonly known as the Texas beetles. There are only two extant genera, Brachypsectra and Asiopsectra. Brachypsectra has a cosmopolitan distribution, mostly in arid regions, while Asiopsectra is found in Central Asia and the Middle East.
Rhinorhipus is a genus of beetles that contains a single species, Rhinorhipus tamborinensis from southern Queensland, Australia. It is the sole member of the family Rhinorhipidae and superfamily Rhinorhipoidea. It is an isolated lineage not closely related to any other living beetle, estimated to have split from other beetles at least 200 million years ago, with studies either considering them the earliest diverging member of Elateriformia, or a basal lineage within Polyphaga. They exhibit feigning death (thanatosis) when disturbed. Their ecology is poorly known. It is likely that they are fossorial based on their morphology.
Eucnemidae, or false click beetles, are a family of elateroid beetles including about 1700 species distributed worldwide.
Elmidae, commonly known as riffle beetles, is a family of beetles in the superfamily Byrrhoidea described by John Curtis in 1830. Both adults and larvae are usually aquatic, living under rocks in fast-flowing shallow areas of streams, such as riffles, feeding on algae and biofilms. There are more than 150 genera and 1,500 described species in Elmidae. The oldest record of the group is Cretohypsilara from the Cenomanian aged Burmese amber.
Harley Procter Brown Jr. was an American biologist and an expert in certain types of aquatic beetles. He described over forty new species in his career.
Omethidae is a family of Elateroidea sometimes known as the false soldier beetles. They are native to South, Southeast and Eastern Asia and the Americas. Their biology is obscure and their larvae are unknown. They appear to inhabit vegetation in or surrounding forests, and are probably active during the day.
Ptilodactylidae is a family of beetles belonging to the Elateriformia. There around 500 extant species in 35 genera. They are generally associated with riparian and aquatic habitats. The larvae generally live associated with rotting wood or vegetation, or within gravel and detritus on the edge of water bodies. The larvae of some species feed on submerged rotting wood or on plant roots, while the adults of some species are known to feed on fungus with modified brush-like maxillae.
Dascillidae is a family of beetles within the clade Elateriformia. There are about 100 extant species in 11 genera, which are found worldwide. Dascillidae together with Rhipiceridae form the super family Dascilloidea.
Podabrocephalus is an enigmatic monotypic genus in the family Ptilodactylidae. For decades it had historically been placed in its own family, Podabrocephalidae, or sometimes included in the highly diverse family Cerambycidae, but more recent analyses firmly place it within Ptilodactylidae. Its only species is Podabrocephalus sinuaticollis, known from southern India.
Gymnochthebius seminole is a species of tiny beetle in the family Hydraenidae. It is known only from a single adult male specimen collected in a "sawgrass-mangrove area" along the Snake Bight Trail north of Flamingo in Everglades National Park, Florida on 27 August 1965. This specimen was 1.20 millimetres (0.047 in) long, with a relatively robust body. It is most similar to G. oppositus. The species is named for the Seminole people of Florida.
