Riffle-beetle
Guides
Ampumixis
Ampumixis is a monotypic genus of riffle beetles in the family Elmidae, containing the single species Ampumixis dispar. The genus was described by Sanderson in 1954 and is endemic to the Western United States, specifically the region between California and Oregon. Adults are small, measuring approximately 2.1–2.5 mm in length.
Ancyronyx
spider water beetles, spider riffle beetles
Ancyronyx is a genus of aquatic riffle beetles in the family Elmidae, commonly known as spider water beetles or spider riffle beetles. The genus comprises 21 described species distributed across North America, South Asia, China, and Southeast Asia, with the Philippines recognized as a center of diversity containing 11 endemic species. Members are obligate inhabitants of lotic freshwater environments, where both adults and larvae cling to submerged substrates using their elongated legs and strong claws. The genus is notable for its potential use as a bioindicator of water quality due to its sensitivity to pollution and oxygen levels.
Ancyronyx variegata
Spider Water Beetle
Ancyronyx variegata is a riffle beetle (Elmidae) commonly known as a Spider Water Beetle, characterized by extremely long legs and often a cross-like elytral color pattern that gives it a spider-like appearance. It inhabits clean, pristine running waters in lotic environments and has been studied for its life history and energetics in Northwest Arkansas and Southeast Texas. The species exhibits a univoltine life cycle with adults present year-round.
Atractelmis wawona
Wawona Riffle Beetle
Atractelmis wawona is a species of riffle beetle in the family Elmidae, described by Chandler in 1954. The common name 'Wawona Riffle Beetle' references Wawona, a location in California's Sierra Nevada. Like other elmids, it inhabits aquatic environments with flowing water. Very few observations or detailed studies of this species have been published.
Bryelmis
Bryelmis is a genus of riffle beetles in the family Elmidae, established by Barr in 2011. The genus contains three described species, all described in the same 2011 publication: Bryelmis idahoensis, Bryelmis rivularis, and Bryelmis siskiyou. As members of Elmidae, these beetles are aquatic and associated with flowing water habitats. The genus is relatively newly described and appears to be restricted to western North America based on species epithets.
Bryelmis idahoensis
riffle beetle
Bryelmis idahoensis is a species of riffle beetle in the family Elmidae, described by Barr in 2011. Riffle beetles are aquatic insects that inhabit fast-flowing streams and rivers. The species is known from North America, with its specific epithet suggesting a connection to Idaho. As with other members of Elmidae, it likely has an aquatic larval stage and a partially aquatic adult stage, though specific biological details for this species remain undocumented in available sources.
Cleptelmis
Cleptelmis is a genus of riffle beetles in the family Elmidae, established by Sanderson in 1954. The genus contains at least two described species: Cleptelmis addenda and Cleptelmis ornata. Riffle beetles in this family are aquatic insects associated with flowing water habitats.
Cleptelmis addenda
Cleptelmis addenda is a species of riffle beetle in the family Elmidae, first described by Fall in 1907. Riffle beetles are aquatic insects adapted to life in fast-flowing streams and rivers. The species is known from North America, though specific details about its biology remain poorly documented.
Cylloepus
riffle beetles
Cylloepus is a genus of riffle beetles in the family Elmidae, first described by Erichson in 1847. The genus contains approximately six described species distributed across the Americas. Members are aquatic beetles associated with flowing water habitats. Species have been documented from North America, the Caribbean, and South America.
Cylloepus abnormis
riffle beetle
Cylloepus abnormis is a species of riffle beetle in the family Elmidae, first described by Horn in 1870. The species is distributed across Central America and North America. As a member of the Elmidae family, it is adapted to aquatic habitats, particularly flowing water environments.
Cylloepus parkeri
Parker's cylloepus riffle beetle
Cylloepus parkeri is a species of riffle beetle in the family Elmidae, described by Sanderson in 1953. It is known from North America and belongs to a group of beetles specialized for living in fast-flowing aquatic environments. The species epithet honors an individual with the surname Parker.
Dubiraphia brevipennis
Dubiraphia brevipennis is a species of riffle beetle in the family Elmidae, described by Hilsenhoff in 1973. Like other elmid beetles, it is adapted to life in flowing water environments. The species is known from North America, though specific details about its biology and ecology remain limited in the available literature.
Dubiraphia browni
Dubiraphia browni is a species of riffle beetle (family Elmidae) described by Hilsenhoff in 1973. As a member of the Elmidae, it belongs to a family of aquatic beetles adapted to living in fast-flowing freshwater habitats. The species is known from North America.
Dubiraphia giulianii
Giuliani's Dubiraphian Riffle Beetle
Dubiraphia giulianii is a species of riffle beetle (family Elmidae) described by Van Dyke in 1949. Like other elmid beetles, it is adapted to life in flowing water environments. The species is known from North America, though detailed biological information remains limited.
Dubiraphia harleyi
Dubiraphia harleyi is a species of riffle beetle in the family Elmidae, described by Barr in 1984. Riffle beetles are aquatic beetles that inhabit flowing water environments. The species is known from North America.
Dubiraphia minima
riffle beetle
Dubiraphia minima is a species of riffle beetle in the family Elmidae, first described by Hilsenhoff in 1973. As a member of this family, it is adapted to aquatic or semi-aquatic habitats in flowing water systems. The species is known from North America, with confirmed records from Manitoba and Ontario in Canada.
Dubiraphia parva
little dubiraphian riffle beetle
Dubiraphia parva is a species of riffle beetle in the family Elmidae, described by Hilsenhoff in 1973. It is found in North America. The species is commonly known as the little dubiraphian riffle beetle.
Dubiraphia quadrinotata
riffle beetle
Dubiraphia quadrinotata is a species of riffle beetle in the family Elmidae. It is found in North America. The specific epithet 'quadrinotata' suggests four spots or markings, though detailed morphological descriptions are not readily available in the provided sources.
Dubiraphia vittata
Banded Riffle Beetle
Dubiraphia vittata is a species of riffle beetle in the family Elmidae. It is found in North America, with records from Alberta and Manitoba in Canada. The species was originally described as Elmis vittata by Melsheimer in 1844. Riffle beetles in this family are typically associated with aquatic habitats, particularly flowing waters.
Elminae
riffle beetles
Elminae is a subfamily of riffle beetles (family Elmidae) comprising at least 120 genera and over 1,300 described species. Members are primarily aquatic, inhabiting running water habitats across all major biogeographic regions. The subfamily exhibits considerable morphological diversity, with some genera showing pronounced secondary sexual dimorphism and miniaturization traits.
Gonielmis
Gonielmis is a genus of riffle beetles (family Elmidae) described by Sanderson in 1954. These beetles are aquatic insects associated with flowing water habitats. The genus belongs to the tribe Elmini within the subfamily Elminae. Taxonomic status varies between sources, with some treating it as a synonym of Heterlimnius while others recognize it as valid.
Heterelmis glabra
riffle beetle
Heterelmis glabra is a species of riffle beetle in the family Elmidae, found in Central America and North America. The largest known populations occur in springs associated with the upper Devils River in south-central Texas. As a spring-adapted organism, it has life-history patterns requiring surface habitat components, making it vulnerable to changes in spring flow. The species has been studied using N-mixture models to assess abundance and distribution across spring sources.
Heterelmis obesa
riffle beetle
Heterelmis obesa is a species of riffle beetle in the family Elmidae, first described by Sharp in 1882. It is one of the most widely distributed species in the genus Heterelmis, occurring across Central America, North America, and South America. The species is recognized as having two subspecies: Heterelmis obesa obesa and Heterelmis obesa plana Hinton, 1936. Like other elmid beetles, it is adapted to aquatic environments with flowing water.
Heterelmis obscura
Heterelmis obscura is a species of riffle beetle in the family Elmidae, first described by Sharp in 1882. It inhabits freshwater environments in Central and South America. Like other elmid beetles, it is fully aquatic throughout its life cycle, with adults possessing a plastron—a layer of air trapped by body hairs that enables underwater respiration.
Heterelmis simplex
Heterelmis simplex is a species of riffle beetle (family Elmidae) described by Sharp in 1882. As a member of the genus Heterelmis, it shares characteristics with other riffle beetles including an aquatic lifestyle and dependence on well-oxygenated water. The species has been recorded in the Caribbean, Middle America, and South America. Unlike the well-studied endangered congener Heterelmis comalensis from Texas, detailed biological information for H. simplex appears limited in published sources.
Heterelmis vulnerata
riffle beetle
Heterelmis vulnerata is a species of riffle beetle in the family Elmidae, first described by LeConte in 1874. It is distributed across Central America and North America. Riffle beetles are aquatic insects that inhabit fast-flowing, oxygen-rich waters where they spend their entire life cycle submerged. Adults possess a plastron—a layer of air trapped by body hairs that allows them to breathe underwater without surfacing.
Heterlimnius corpulentus
Corpulent Riffle Beetle
Heterlimnius corpulentus is a species of riffle beetle in the family Elmidae, commonly known as the Corpulent Riffle Beetle. It was described by LeConte in 1874 and is found in western North America, with records from the Canadian provinces of Alberta and British Columbia. Riffle beetles in this family are aquatic and associated with flowing water habitats.
Hexacylloepus
riffle beetles
Hexacylloepus is a genus of riffle beetles in the family Elmidae, established by Hinton in 1940. The genus contains approximately 19 described species. As with other elmid beetles, members of this genus are associated with aquatic habitats, particularly flowing water systems.
Hexacylloepus ferrugineus
Rusty Riffle Beetle, rusty elmid
Hexacylloepus ferrugineus, commonly known as the rusty riffle beetle or rusty elmid, is a species of riffle beetle in the family Elmidae. It is found in Central America and North America. The species was first described by Horn in 1870. Riffle beetles in this family are typically associated with aquatic habitats, particularly flowing water environments.
Huleechius marroni
Huleechius marroni is a species of riffle beetle (family Elmidae) described by Brown in 1981. It belongs to the genus Huleechius, a group of aquatic beetles adapted to flowing water habitats. The species is known from Middle America and North America. Like other elmids, it is presumed to inhabit freshwater streams and rivers, though specific ecological details remain poorly documented.
Macrelmis texana
Macrelmis texana is a species of riffle beetle in the family Elmidae, described by Schaeffer in 1911. It belongs to a genus of aquatic beetles adapted to living in fast-flowing water. The species has been recorded from both Central America and North America.
Macronychus
riffle beetles
Macronychus is a genus of riffle beetles in the family Elmidae, comprising approximately 11 described species. Members of this genus inhabit flowing water environments, particularly riffle zones of streams. The genus was established by Müller in 1806 and includes species distributed across North America, Europe, and Asia.
Macronychus glabratus
riffle beetle
Macronychus glabratus is a species of riffle beetle in the family Elmidae, described by Say in 1825. It inhabits lotic freshwater environments, specifically stream riffles in North America. Research has documented its life cycle, growth, survival, and production in streams of northwest Arkansas and southeast Texas.
Microcylloepus
Microcylloepus is a genus of riffle beetles (family Elmidae) established by Hinton in 1935. The genus contains approximately nine described species distributed primarily in the Americas, with records from the United States to Colombia. These beetles are aquatic and inhabit flowing water environments, particularly springs and spring-runs. One species, Microcylloepus pusillus, has been studied in detail at Comal Springs, Texas, where it coexists with the endangered beetle Heterelmis comalensis.
Microcylloepus similis
Microcylloepus similis is a species of riffle beetle (family Elmidae) described by Horn in 1870. It belongs to a group of aquatic beetles commonly known as elmids or riffle beetles, which are characteristic inhabitants of flowing water habitats. The species is part of the genus Microcylloepus, a group of small aquatic beetles within the subfamily Elminae.
Narpus angustus
Riffle beetle
Narpus angustus is a species of riffle beetle in the family Elmidae, described by Casey in 1893. It is known from North America. Riffle beetles in this family are typically associated with aquatic environments, particularly flowing water habitats.
Narpus concolor
Narpus concolor is a species of riffle beetle in the family Elmidae, first described by LeConte in 1881. It is found in North America, with distribution records from Alberta and British Columbia in Canada. As a member of the Elmidae, it is associated with freshwater environments. The species has been documented in iNaturalist with limited observation records.
Neoelmis caesa
riffle beetle
Neoelmis caesa is a species of riffle beetle in the family Elmidae. It is found in North America. As a member of the Elmidae, it inhabits aquatic environments, specifically riffle habitats in streams and rivers. The species was first described by LeConte in 1874.
Optioservus
Optioservus is a former genus of riffle beetles (family Elmidae) established by Sanderson in 1954. As of 2021, it is recognized as a junior synonym of Heterlimnius. The genus formerly contained approximately 13 species distributed in the Nearctic region, including several species described by White in 1978. Species-level identification historically relied on variable external characters; a 1978 revision established more reliable diagnostic criteria based on male genitalia, elytral patterns, and geographic distribution.
Optioservus browni
Brown's optioservus riffle beetle
Optioservus browni is a species of riffle beetle (family Elmidae) described by White in 1978. The species is known from North America and is part of a genus of aquatic beetles typically found in flowing water habitats. Like other elmid beetles, it is adapted to life in fast-moving streams and rivers.
Optioservus canus
pinnacles optioservus riffle beetle
Optioservus canus is a species of riffle beetle in the family Elmidae, first described by Chandler in 1954. Riffle beetles are aquatic insects that inhabit running water environments. The species is known from North America.
Optioservus castanipennis
Optioservus castanipennis is a species of riffle beetle in the family Elmidae, first described by Fall in 1925. It belongs to a genus of small aquatic beetles inhabiting running water systems. The species is recognized as part of the Nearctic fauna and has been subject to taxonomic revision based on male genitalia and elytral characteristics.
Optioservus divergens
Optioservus divergens is a species of riffle beetle in the family Elmidae. The species was described by LeConte in 1874 and is currently accepted under this name, though it was formerly classified in the genus Heterlimnius. Riffle beetles in this family are aquatic insects typically associated with running water habitats.
Optioservus heteroclitus
Optioservus heteroclitus is a species of riffle beetle in the family Elmidae, described by White in 1978 as part of a taxonomic revision of Nearctic Optioservus. The species was distinguished based on male genitalia, elytral patterns and shape, and geographic distribution. Like other elmid beetles, it is associated with aquatic environments, specifically flowing water habitats.
Optioservus immunis
Optioservus immunis is a species of riffle beetle in the family Elmidae, first described by Fall in 1925. It is one of thirteen Nearctic species in the genus, distinguished from congeners primarily by male genitalia and elytral pattern. The species was previously known under the synonym Optioservus cryophilus.
Optioservus ovalis
Optioservus ovalis is a species of riffle beetle in the family Elmidae, first described by LeConte in 1863. Riffle beetles are aquatic insects whose larvae and adults inhabit running water environments. The species is found in North America, with records from Canada and the United States. Like other elmid beetles, it is likely associated with clean, well-oxygenated streams and rivers.
Optioservus phaeus
Scott optioservus riffle beetle
Optioservus phaeus is a species of riffle beetle (family Elmidae) described by White in 1978. It belongs to a genus of small aquatic beetles inhabiting running waters. The species was described as part of a taxonomic revision based on male genitalia, elytral patterns, and geographic distribution. It is known from a highly restricted range in Kansas.
Optioservus quadrimaculatus
four-spotted riffle beetle
Optioservus quadrimaculatus is a species of riffle beetle in the family Elmidae, described by Horn in 1870. The species is found in North America, with records from Canadian provinces including Alberta, British Columbia, and Saskatchewan. Riffle beetles in this family are aquatic insects associated with running water habitats. The specific epithet "quadrimaculatus" refers to four spots, likely describing a distinctive elytral pattern.
Optioservus sandersoni
A species of riffle beetle in the family Elmidae, endemic to North America. First described by Collier in 1972. Taxonomic identification relies on male genitalia, elytral patterns, and body shape rather than variable external characters.
Optioservus seriatus
Optioservus seriatus is a species of riffle beetle in the family Elmidae, first described by LeConte in 1874. It is one of thirteen Nearctic species in the genus Optioservus, a group whose taxonomy was historically complicated by highly variable external morphology. The species occurs in North America, with records from western Canada including Alberta and British Columbia.