Aquatic-beetles
Guides
Aciliini
Aciliini is a tribe of predaceous diving beetles within the family Dytiscidae, containing approximately 7 genera and at least 69-70 extant species. The tribe includes well-known genera such as Acilius, Graphoderus, and Thermonectus, which are medium to large-sized beetles found in freshwater habitats. Members are recognized as active predators in aquatic ecosystems.
Adephaga
Ground and Water Beetles, adephagans
Adephaga is the second-largest suborder of beetles, comprising over 40,000 species across 10 families. The suborder includes ground beetles (Carabidae), tiger beetles, predaceous diving beetles, and whirligig beetles. Members are characterized by specialized anatomical features including visible notopleural sutures and a first abdominal sternum separated by hind coxae. The vast majority of species belong to the family Carabidae.
Agabinus
Agabinus is a genus of predaceous diving beetles (family Dytiscidae) established by Crotch in 1873. The genus contains two described species: Agabinus glabrellus and Agabinus sculpturellus. Members are found in North America and are classified within the subfamily Agabinae.
Bidessini
Bidessini is a tribe of predaceous diving beetles within the family Dytiscidae, comprising at least 40 genera and over 630 described species. Members are small to minute aquatic beetles found across diverse freshwater habitats worldwide, with notable radiations in Australia, South America, and Madagascar. The tribe includes both surface-dwelling (epigean) and subterranean (stygobitic) species, with several genera exhibiting convergent adaptations to groundwater environments.
Brachyvatus
Brachyvatus is a genus of diving beetles in the family Dytiscidae, first described by Zimmermann in 1919. It belongs to the tribe Bidessini within the subfamily Hydroporinae. The genus contains at least four described species distributed in South America, with records primarily from Colombia. As with other dytiscids, members are aquatic predators.
Byrrhoidea
Pill, Water and Toe-winged Beetles
Byrrhoidea is a superfamily of beetles within Elateriformia, comprising families that are primarily aquatic or semi-aquatic. It includes the families Byrrhidae (pill beetles), Elmidae (riffle beetles), Dryopidae (long-toed water beetles), Limnichidae (minute marsh-loving beetles), Psephenidae (water penny beetles), Heteroceridae (variegated mud-loving beetles), Chelonariidae (turtle beetles), Eulichadidae (forest stream beetles), Callirhipidae (cedar beetles), Cneoglossidae, and Ptilodactylidae. The superfamily was historically split into Dryopoidea, which is no longer recognized as separate. The current circumscription of Byrrhoidea may not be monophyletic, with Buprestoidea nested within it in some phylogenetic analyses.
Chaetarthria
Chaetarthria is a genus of water scavenger beetles in the family Hydrophilidae, first described by Stephens in 1835. The genus contains at least 27 described species. These beetles are placed in the subfamily Chaetarthriinae and tribe Chaetarthriini. They are small aquatic beetles associated with freshwater habitats.
Chaetarthriinae
Chaetarthriinae is a subfamily of aquatic beetles in the family Hydrophilidae, containing 92 species in 8 genera. The subfamily is divided into two tribes: Chaetarthriini and Anacaenini. Larvae exhibit morphological diversity reflecting adaptation to varied environments. Phylogenetic analyses based on larval characters have not recovered the subfamily as monophyletic, with Chaetarthria diverging early due to unique modifications associated with riparian habitats.
Clemnius
Clemnius is a genus of diving beetles in the family Dytiscidae, established in 2017 to accommodate species previously placed in related genera. The genus belongs to the tribe Hygrotini within the subfamily Hydroporinae. Species in this genus are small to medium-sized diving beetles adapted to aquatic habitats. The genus has been documented from Southeast Asia based on collection records.
Coelostomatini
Coelostomatini is a tribe of water scavenger beetles within the family Hydrophilidae, containing approximately 7 genera and more than 70 described species. The tribe was established by Heyden in 1891. Members of this tribe are classified in the subfamily Sphaeridiinae and share morphological characteristics typical of this group, including compact body forms. The tribe includes genera such as Coelostoma, Dactylosternum, and Pelosoma, which are distributed across various regions globally.
Copelatinae
copelatine diving beetles
Copelatinae is a subfamily of predaceous diving beetles (Dytiscidae) comprising seven genera: Agaporomorphus, Aglymbus, Copelatus, Exocelina, Lacconectus, Liopterus, and Madaglymbus. The genus Copelatus is the largest with approximately 470 described species worldwide, showing greatest diversity in tropical South America, Africa, and Southeast Asia. Members are predominantly aquatic, though some species have colonized highly ephemeral habitats including forest floor depressions. The subfamily exhibits remarkable morphological diversity and includes phylogenetically isolated lineages such as the South African genus Capelatus.
Coptotominae
Coptotominae is a small subfamily of predaceous diving beetles (family Dytiscidae) containing the single genus Coptotomus. The genus comprises approximately six described species distributed in North America and the Neotropics. These beetles are aquatic predators inhabiting freshwater environments. The subfamily was established by Branden in 1885 and represents a distinct lineage within the diverse diving beetle fauna.
Crenitulus
Crenitulus is a genus of small water scavenger beetles in the family Hydrophilidae, tribe Anacaenini. The genus was established by Winters in 1926 and is part of the subfamily Chaetarthriinae. Members of this genus are aquatic or semi-aquatic beetles associated with freshwater habitats. The genus is poorly documented in the scientific literature, with limited species-level information available.
Desmopachria
Desmopachria is a genus of predaceous diving beetles in the family Dytiscidae, tribe Hyphydrini. The genus contains over 80 described species distributed primarily in the Americas, from the United States through Central America to South America, with particular diversity in the Amazon basin and Caribbean islands. Species are associated with aquatic habitats including river floodplains and high-altitude forest streams. Multiple new species have been described in recent decades, indicating ongoing taxonomic work and likely remaining undescribed diversity.
Dianous
Dianous is a genus of rove beetles in the subfamily Steninae, characterized by their specialized ability to glide across water surfaces. All representatives of this genus possess pygidial glands that secrete alkaloid and terpene compounds, including stenusine and related molecules, which reduce water surface tension to enable rapid skimming locomotion. The genus has been documented across Europe, Asia, and North America, with particular taxonomic attention in China and Turkey where multiple new species have been described in recent years. Dianous species are specialist predators of small invertebrates.
Didactyliini
Didactyliini is a small tribe of water scavenger beetles within the family Hydrophilidae, currently containing the single genus Didactylus. Members of this tribe are aquatic beetles distinguished by reduced tarsal segmentation, with only two visible tarsomeres on the fore and mid legs. The tribe was established to accommodate this unusual morphological condition, which separates it from other Hydrophilinae. The genus occurs in the Neotropical region, where species inhabit freshwater environments.
Dubiraphia
riffle beetles
Dubiraphia is a genus of riffle beetles in the family Elmidae, established by Sanderson in 1954. The genus contains approximately 11 described species distributed in North America. These beetles are aquatic or semi-aquatic, inhabiting flowing water environments. Species within Dubiraphia are distinguished by morphological features of the elytra and male genitalia.
Elodes
marsh beetles
Elodes is a genus of marsh beetles in the family Scirtidae, containing more than 60 described species. These beetles inhabit aquatic and semi-aquatic environments where they are associated with marshy vegetation and slow-moving water bodies. The genus has been subject to ecological study regarding population dynamics and seasonal abundance patterns in wetland habitats.
Gymnusa
Gymnusa is a genus of small rove beetles in the tribe Gymnusini, characterized by uniformly dark coloration and semi-aquatic to aquatic habits. Species range from 4.2 to 6.5 mm in length and inhabit detritus-rich wetlands across the Nearctic and Palearctic regions.
Haliplus
crawling water beetles
Haliplus is a genus of small crawling water beetles comprising at least 180 described species. Members range from 1.75 to 5 mm in length and inhabit freshwater margins worldwide except Antarctica. The genus has been subject to recent taxonomic revision, including synonymization of H. wehnckei with H. sibiricus based on morphometric and genetic evidence.
Heteroceridae
Variegated Mud-loving Beetles
Heteroceridae, commonly known as variegated mud-loving beetles, are a family of small, dorsoventrally depressed beetles inhabiting shorelines worldwide. Approximately 250 species are recognized globally, with highest diversity in tropical and subtropical regions. The family exhibits remarkable phenotypic uniformity in external morphology, making species identification difficult without examination of male genitalia. These beetles construct shallow tunnels in damp soils and have been documented on every continent except Antarctica.
Hydaticini
Hydaticini is a tribe of diving beetles (family Dytiscidae, subfamily Dytiscinae) established by Sharp in 1880. Members of this tribe are aquatic predators found in freshwater habitats. The tribe includes the genus Hydaticus, with species documented from the Neotropics including the Amazon basin and Brazilian highlands.
Hydrochidae
Elongate Water Scavenger Beetles
Hydrochidae is a family of aquatic beetles in the order Coleoptera, containing a single genus Hydrochus with approximately 180–200+ species worldwide. These small elongate water scavenger beetles are found in freshwater habitats across multiple continents including Europe, Asia, Africa, and the Americas. The family is sometimes treated as the subfamily Hydrochinae within Hydrophilidae. Species-level taxonomy is well-developed, with recent revisions documenting substantial diversity in Central America (26 species), South America (77 species in Bolivia, Brazil, and Paraguay alone), and the Mediterranean region.
Hydrodytinae
Hydrodytinae is a subfamily of predaceous diving beetles in the family Dytiscidae, established by K. B. Miller in 2001. It contains at least two genera and four described species. The genus Hydrodytes occurs in North America and the Neotropics, while Microhydrodytes is restricted to the Neotropics. This subfamily represents a relatively recently recognized lineage within the diverse diving beetle fauna.
Hydrophilinae
water scavenger beetles
Hydrophilinae is the largest subfamily of water scavenger beetles (family Hydrophilidae), containing approximately 1852 species in 61 genera and 8 tribes. The subfamily was revised by Short and Fikáček in 2013, which recognized five tribes: Amphiopini, Berosini, Hydrobiusini, Hydrophilini, and Laccobiini. Members are predominantly aquatic beetles found across diverse geographic regions including the Neotropics and Asia. Some genera represent ancient, possibly relict lineages with unusual morphological character combinations.
Hydrophilus
Giant Water Scavenger Beetles
Hydrophilus is a genus of large aquatic beetles in the family Hydrophilidae, commonly known as giant water scavenger beetles. The genus comprises approximately 48 species arranged in three subgenera: Hydrophilus, Dibolocelus, and Temnopterus. These beetles are among the largest aquatic insects in their range, with some species reaching substantial size. Members of this genus are fully aquatic as adults, possess the ability to disperse by flight, and exhibit distinct feeding mode shifts during development—carnivorous larvae transition to omnivorous adults. Several species are rare or endangered in parts of their range, including the great silver water beetle Hydrophilus piceus in Britain.
Hydroscaphidae
skiff beetles
Hydroscaphidae is a small family of water beetles in the suborder Myxophaga, commonly known as skiff beetles. The family contains approximately 23 species as of 2010, distributed across four genera. These beetles are highly specialized for life in thin films of water over algal surfaces.
Laccobiini
Laccobiini is a tribe of aquatic beetles within the family Hydrophilidae, containing 367 species distributed across 8 genera. Members are small to minute water scavenger beetles occupying diverse freshwater habitats across multiple continents. The tribe includes the well-known genus Laccobius and the hygropetric-specialist genus Oocyclus.
Lara
Lara is a genus of beetles in the family Elmidae, commonly known as riffle beetles. The genus was established by John Lawrence LeConte in 1852. Members of this genus are aquatic beetles associated with flowing water habitats. The genus is classified within the subfamily Larainae, which contains other genera of similar aquatic beetles.
Limnebius
minute moss beetles
Limnebius is a genus of minute moss beetles in the family Hydraenidae, containing over 160 described species. The genus exhibits uniform external morphology but highly variable male genitalia, ranging from curved rod shapes in the subgenus Bilimneus to complex structures with up to seven longitudinal folds or appendages in Limnebius s.str. Species occur across multiple continents including Europe, Africa, Australia, and Papua New Guinea. The genus has been extensively studied for its morphological diversification and patterns of sexual dimorphism.
Limnichinae
minute marsh-loving beetles
Limnichinae is a subfamily of minute marsh-loving beetles within the family Limnichidae, containing over 20 genera and approximately 330 described species. Members are characterized by small size, elongate-oval body form, and association with riparian and aquatic habitats. The genus Byrrhinus is the most species-rich in the subfamily, with at least 87 species distributed pantropically. Adults are frequently collected using light traps near water bodies.
Lutrochidae
Travertine Beetles
Lutrochidae is a small family of aquatic beetles commonly known as travertine beetles. The family has been reported from hygropetric habitats for the first time in Venezuela, expanding beyond their previously known association with travertine-depositing springs and streams in North America. Species occur in the Americas from the United States through the Neotropics, with recent revisions documenting new species from Venezuela, the Guianas, and the Lesser Antilles.
Lutrochus
travertine beetles
Lutrochus is the sole genus in the family Lutrochidae, a group of small aquatic beetles commonly called travertine beetles. The genus contains approximately 21 species distributed from the southern United States through Central America to Brazil. Both adults and larvae inhabit shallow, fast-flowing streams where they are specifically associated with submerged decaying wood and travertine deposits.
Matinae
Matinae is a subfamily of predaceous diving beetles within the family Dytiscidae. It contains at least 3 genera (Allomatus, Batrachomatus, and Matus) and approximately 10 described species. These beetles are aquatic predators found in freshwater habitats.
Metaxydytes
Metaxydytes is a genus of predaceous diving beetles in the subfamily Cybistrinae, endemic to the Neotropics. The genus comprises nine species that were reclassified from the genus Megadytes based on phylogenetic and morphological evidence. These are large aquatic beetles adapted to freshwater habitats. The genus was established to accommodate species previously considered part of a broader Megadytes concept.
Nebrioporus
Nebrioporus is a genus of diving beetles (Dytiscidae) established by Régimbart in 1906. The genus has been divided into eight species-groups based on morphological character analysis, replacing historical subgeneric divisions. It contains numerous species distributed across Europe, North Africa, the Middle East, and Asia, with the N. depressus-group being the most speciose.
Neoclypeodytes
Neoclypeodytes is a genus of small diving beetles in the family Dytiscidae, tribe Bidessini, distributed across western North America and northern Central America. The genus was revised in 2001, with 25 valid species recognized and 11 new species described. A single synapomorphy—two maculae on each elytron—supports its monophyly. Relationships to other bidessine genera remain unresolved.
Neohaemonia
Pale pondweed leaf beetles
Neohaemonia is a genus of aquatic leaf beetles in the family Chrysomelidae, established by Székessy in 1941. The genus contains at least four described species distributed in North America. Members are commonly known as pale pondweed leaf beetles. These beetles are associated with aquatic habitats and feed on pondweeds (Potamogeton species).
Novochares
water scavenger beetles
Novochares is a genus of water scavenger beetles (Hydrophilidae: Acidocerinae) erected in 2021 to accommodate New World species previously placed in Helochares. The genus contains 52 described species distributed across the entire Neotropical region from Mexico to Argentina, including Caribbean islands. Species circumscription relies heavily on male aedeagus morphology due to relatively homogeneous external characteristics. An integrative taxonomic approach combining adult morphology with COI and 28S DNA sequence data was used to delimit species boundaries.
Ochthebiinae
minute moss beetles
Ochthebiinae is a subfamily of minute moss beetles (family Hydraenidae) comprising approximately 14 genera and over 650 described species. It represents the second most species-rich subfamily within Hydraenidae and exhibits exceptional ecological diversity, including terrestrial species and those inhabiting nearly all aquatic environments from freshwater to hypersaline waters. The subfamily contains two tribes: Ochtheosini (four species in three genera) and the much larger Ochthebiini. Molecular phylogenetic studies have revised the classification of Ochthebiini, recognizing six genera and establishing multiple subgenera within the diverse genus Ochthebius.
Oodini
Oodini is a tribe of ground beetles (Carabidae: Harpalinae) containing over 400 species in 43 genera, with highest diversity in tropical Africa. Members are generally associated with standing water habitats. The tribe is distinguished by two diagnostic morphological characters: a laterally coadunate metepisternum and an elytral ridge formed by fusion of elytral intervals 7 and 8.
Ora
flea marsh beetles
Ora is a genus of flea marsh beetles in the family Scirtidae, containing approximately 17 described species. These small beetles inhabit wetland environments and are characterized by their association with marshy habitats. The genus was established by Clark in 1865 and represents one of several genera within the Scirtidae family, which are commonly known as marsh beetles.
Peltodytes floridensis
Peltodytes floridensis is a species of crawling water beetle in the family Haliplidae, first described by Matheson in 1912. The genus Peltodytes is distinguished from other haliplid genera by the presence of a distinct pronotal plica—a longitudinal groove or fold on the pronotum. Species in this genus are associated with aquatic or semi-aquatic habitats.
Plateumarini
Plateumarini is a tribe of leaf beetles within the subfamily Donaciinae, established by Böving in 1922. Members of this tribe are aquatic or semi-aquatic beetles associated with freshwater habitats. The tribe is distinguished from the related tribe Donaciini by morphological features of the larval stage, particularly in the structure of the respiratory siphon. Plateumarini contains the genus Plateumaris, which is the primary genus in this group.
Plateumaris
spade reed beetles
Plateumaris is a genus of aquatic leaf beetles in the family Chrysomelidae, subfamily Donaciinae, distributed across the Holarctic region. The genus comprises approximately 27 species globally, with 17 described in North America and 10 in the Palaearctic. Adults are found along margins of water bodies on emergent aquatic plants, while larvae develop submerged on plant roots. Species are recognized by diagnostic morphological features including the lack of pubescence above the procoxa and rounded, declivous elytral apices with a sinuate sutural area. Females possess a strongly sclerotized, shovel-like ovipositor that often protrudes from the abdomen, giving rise to the common name "spade reed beetles".
Postelichus
long-toed water beetles
Postelichus is a genus of long-toed water beetles in the family Dryopidae, established by Nelson in 1989. The genus contains seven described species distributed in North America, with the earliest described species dating to 1852. Members of this genus are associated with aquatic or semi-aquatic habitats, consistent with the family Dryopidae's ecological preferences.
Psephenidae
Water Penny Beetles, Water Pennies
Psephenidae, commonly known as water penny beetles, is a family of aquatic beetles in the order Coleoptera. The family comprises approximately 272 species in 35 genera distributed across all continents in both tropical and temperate regions. Larvae are fully aquatic and bear a distinctive flattened, circular shape resembling a penny, from which the common name derives. Adults are typically terrestrial, short-lived, and non-feeding. The family is divided into two subfamilies: Eubriinae and Psepheninae.
Psepheninae
water-penny beetles
Psepheninae is a subfamily of Psephenidae (Coleoptera: Polyphaga) containing water-penny beetles, named for the distinctive flattened, oval larvae that resemble pennies. The subfamily includes at least six genera: Psephenus, Psephenops, Pheneps, Psephenotarsis, Psephenopalpus, and Belicinus. Members are strictly aquatic and occur in the New World from North America through Central America to South America.
Ptilodactyla
toe-winged beetles
Ptilodactyla is a large and cosmopolitan genus of toe-winged beetles comprising approximately 370–380 described species, representing roughly 70% of all species in the family Ptilodactylidae. The genus is characterized by distinctive morphological features including pectinate male antennae with articulated rami, incomplete lateral pronotal carinae anteriorly, concealed trochantins, and pseudotetramerous tarsi with reduced tarsomere IV and lobed tarsomere III. Fossil records extend to the Eocene, with specimens described from Baltic amber (Russia) and Rovno amber (Ukraine). Some species have been introduced outside their native ranges through human activity.
Ptilodactylidae
Toe-winged Beetles
Ptilodactylidae is a family of approximately 500 extant species in 35 genera, commonly known as toe-winged beetles. The family belongs to the superfamily Dryopoidea within Elateriformia. Members are primarily associated with riparian and aquatic habitats, with larvae typically found in rotting wood, vegetation, or gravel and detritus at water margins. The family has a significant but underappreciated fossil record, including specimens preserved in Baltic, Dominican, Mexican, and Rovno amber dating from the Cretaceous through Eocene.