Byrrhoidea is a superfamily of beetles belonging to
Elateriformia
Elateriformia is an infraorder of polyphagan beetles. The two largest families in this group are buprestids, of which there are around 15,000 described species, and click beetles, of which there are around 10,000 described species.
The infraor ...
that includes several families which are either aquatic or associated with a semi-aquatic habitat. Other than the superfamily
Hydrophiloidea
Hydrophiloidea, known as water scavenger beetles, is a superfamily of beetles. Until recently it included only a single family, the Hydrophilidae (water scavenger beetles), but several of the subfamilies have been removed and raised to family ra ...
, most of the remaining
Polyphaga
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 b ...
n beetles which are aquatic are in this superfamily.
Description
Adults of many Byrrhoidea have exocone eyes (with expanded corneal lens). The anterior edge of the scutellar shield is often abruptly elevated (except in
Psephenidae
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. The young, which live in water, resemble tiny pennies. The larv ...
and
Cneoglossidae
Cneoglossidae is a family of beetles in the superfamily Byrrhoidea, containing nine described species in a single genus, ''Cneoglossa,'' which are native to the Neotropics
The Neotropical realm is one of the eight biogeographic realms const ...
). A variety of byrrhoids have the first three abdominal ventrites solidly fused together.
Larvae of most Limnichiidae have one pair of anal hooks on the tenth abdominal segment, while Cneoglossidae and
Ptilodactylidae
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 veg ...
have three or more hooks on each side of this segment. Larvae of
Lutrochidae
Lutrochidae is a family of water beetles with a single genus ''Lutrochus'' sometimes known as "travertine beetles". There are around 21 species native to the Americas from the southern United States to Brazil.
They are distinguished by their ov ...
and Elmidae, as well as the limnichiid genus ''Hyphalus'', have anal gill tufts. Almost all byrrhoid larvae have anterior abdominal spiracles that are biforous (or bilabiate) in shape.
The degree of
wing
A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is expres ...
development varies among Byrrhoidea, with macroptery (wings fully developed),
brachyptery
Brachyptery is an anatomical condition in which an animal has very reduced wings. Such animals or their wings may be described as "brachypterous". Another descriptor for very small wings is microptery.
Brachypterous wings generally are not functi ...
(wings reduced), microptery (wings reduced to small remnants) and
aptery
Aptery is the anatomical condition of an animal completely lacking any kind of wings. An animal with this condition is said to be apterous.
Most animal species belong to and are phylogenetic descendants of apterous taxa. These groups are said to ...
(no wings) all occurring in the superfamily. Within family
Elmidae
Elmidae, commonly known as riffle beetles, is a family (biology), family of beetles in the superfamily Byrrhoidea described by John Curtis (entomologist), John Curtis in 1830. Both adults and larvae are usually aquatic, living under rocks in fas ...
, subfamily
Larainae
Larainae is a subfamily of riffle beetles in the family Elmidae. There are more than 20 genera and 160 described species in Larainae.
Genera
These 28 genera belong to the subfamily Larainae:
* '' Disersus'' Sharp, 1882
* '' Dryopomorphus'' Hami ...
has only macropterous wings, while other wing types are common in subfamily
Elminae
Elminae is a subfamily of riffle beetles in the family Elmidae. There are at least 120 genera and more than 1,300 described species in Elminae.
Genera
These genera belong to the subfamily Elminae.
* '' Aesobia'' Jäch, 1982
* '' Amazonopsis'' B ...
. Within family
Dryopidae
Dryopidae is a family of beetles, commonly named long-toed water beetles, in the superfamily Byrrhoidea. It was described by Gustaf Johan Billberg in 1820.
Description
Long-toed water beetles are named for their extended claws. Adults have dens ...
, the genera with aquatic or semiaquatic adults are almost always macropterous, while genera with terrestrial adults are almost always apterous and the subterranean ''
herbivorous
A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...
, feeding on
algae
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...
,
moss
Mosses are small, non-vascular flowerless plants in the taxonomic division Bryophyta (, ) '' sensu stricto''. Bryophyta (''sensu lato'', Schimp. 1879) may also refer to the parent group bryophytes, which comprise liverworts, mosses, and hor ...
,
liverworts
The Marchantiophyta () are a division of non-vascular land plants commonly referred to as hepatics or liverworts. Like mosses and hornworts, they have a gametophyte-dominant life cycle, in which cells of the plant carry only a single set of ge ...
,
lichens
A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among hypha, filaments of multiple fungus, fungi species in a mutualism (biology), mutualistic relationship.grass
Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns an ...
roots.
Phylogeny
Byrrhoidea in its current state may not be
monophyletic
In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...
. Multiple studies have found
Buprestoidea
Buprestoidea is a superfamily of beetle
Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insect ...
to be nested within it. Recent phylogenies have split out the grouping Dryopoidea, including Dryopidae, Elmidae, Limnichidae, Heteroceridae, Chelonariidae, Eulichadidae, Callirphidae, Ptilodactylidae and the extinct family Mastigocoleidae., with phylogenies finding the group more closely related to
Elateroidea
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.
Description
Elateroidea is a morphologically diverse group, i ...