The Cupedidae are a small family of beetles, notable for the square pattern of "windows" on their elytra, which give the family their common name of reticulated beetles.
The whirligig beetles are water beetles, comprising the family Gyrinidae that usually swim on the surface of the water if undisturbed, though they swim underwater when threatened. They get their common name from their habit of swimming rapidly in circles when alarmed, and are also notable for their divided eyes which are believed to enable them to see both above and below water. The family includes some 700 extant species worldwide, in 15 genera, plus a few fossil species. Most species are very similar in general appearance, though they vary in size from perhaps 3 mm to 18 mm in length. They tend to be flattened and rounded in cross section, in plain view as seen from above, and in longitudinal section. In fact their shape is a good first approximation to an ellipsoid, with legs and other appendages fitting closely into a streamlined surface. Whirligig beetles belong to the beetle suborder Adephaga, which also includes ground beetles and diving beetles.
The Adephaga are a suborder of beetles, and with more than 40,000 recorded species in 10 families, the second-largest of the four beetle suborders. Members of this suborder are collectively known as adephagans. The largest family is Carabidae which comprises most of the suborder with over 40,000 species. Adephaga also includes a variety of aquatic beetles, such as predaceous diving beetles and whirligig beetles.
The Trachypachidae are a family of beetles that generally resemble small ground beetles, but that are distinguished by the large coxae of their rearmost legs. There are only six known extant species in the family, with four species of Trachypachus found in northern Eurasia and northern North America, and two species of Systolosoma in Chile and Argentina. They were much more diverse in the past, with dozens of described species from the Mesozoic.
The Dytiscidae – based on the Greek dytikos (δυτικός), "able to dive" – are the predaceous diving beetles, a family of water beetles. They occur in virtually any freshwater habitat around the world, but a few species live among leaf litter. The adults of most are between 1 and 2.5 cm (0.4–1.0 in) long, though much variation is seen between species. The European Dytiscus latissimus and Brazilian Megadytes ducalis are the largest, reaching up to 4.5 cm (1.8 in) and 4.75 cm (1.9 in) respectively. In contrast, the smallest is likely the Australian Limbodessus atypicali of subterranean waters, which only is about 0.9 mm (0.035 in) long. Most are dark brown, blackish, or dark olive in color with golden highlights in some subfamilies. The larvae are commonly known as water tigers due to their voracious appetite. They have short, but sharp mandibles and immediately upon biting, they deliver digestive enzymes into prey to suck their liquefied remains. The family includes more than 4,000 described species in numerous genera.
Hydrophiloidea, known as water scavenger beetles, is a superfamily of beetles. Until recently it included only a single family, the Hydrophilidae, but several of the subfamilies have been removed and raised to family rank. Hydrophiliidae remains by far the largest member of the group, with nearly 3,000 described species. The other families have no more than 400 species. The Histeroidea are closely related and sometimes considered part of a sensu lato Hydrophiloidea. The majority of the clade is aquatic, which is thought to be the ancestral ecology of the group, with some lineages like Sphaeridiinae becoming secondarily terrestrial. Modern representatives of the group first appeared during the Late Jurassic.
Coptoclavidae is an extinct family of aquatic beetles in the suborder Adephaga. The Coptoclavidae lived from the Late Triassic to the Early Cretaceous. Coptoclavidae is a member of the adephagan clade Dytiscoidea, which contains other aquatic beetles. Suggested reasons for their extinction to include the rise of teleost fish, or competition with Gyrinidae and Dytiscidae, which possess defensive secretions and sucking channels in the mandibles of larvae, which coptoclavids likely lacked. It has been suggested that the genus Timarchopsis and the subfamily Timarchopsinae are only distantly related to other coptoclavids based on cladistic analysis, with Timarchopsis being more closely related to geadephagans like carabids and trachypachids instead. Another study also suggested similarly for Coptoclavisca and possibly other coptoclaviscines.
Porrorhynchus is a genus of beetles in the family Gyrinidae, containing the following species:
Enhydrus is a genus of beetles in the family Gyrinidae, containing the following species:
Anagyrinus atavus is an extinct species of fossil beetle in the family Gyrinidae, the only species in the genus Anagyrinus. It is known from the Hettangian aged Insektenmergel Formation of Switzerland
Gyrinoides limbatus is an extinct species of beetle in the family Gyrinidae, the only species in the genus Gyrinoides.
Gyrinopsis antiquus is an extinct species of fossil beetle in the family Gyrinidae, the only species in the genus Gyrinopsis.
Heterogyrus milloti is a species of beetle in the family Gyrinidae, the only species in the genus Heterogyrus. It is endemic to Madagascar, and forms a basal lineage within the family, estimated to have diverged from all other gyrinids 200 million years ago. It is suggested to be closely related to the fossil genera Mesogyrus, Cretotortor and Baissogyrus which constitute the subfamily Heterogyrinae.
Angarogyrus is an extinct genus of fossil beetles in the family Gyrinidae, containing the following species:
Mesodineutes amurensis is an extinct species of fossil beetle in the family Gyrinidae, the only species in the genus Mesodineutes.
Mesogyrus is an extinct genus of fossil beetles in the family Gyrinidae, containing the following species:
Copelatus restrictus is a species of diving beetle. It is part of the genus Copelatus in the subfamily Copelatinae of the family Dytiscidae. It was described by Sharp in 1882.
Dineutus loriae is a species of beetle within the family of whirligig beetles, or Gyrinidae. The species name loriae honors the Italian explorer Lamberto Loria (1855–1913). This beetle can reach a length of about 20 mm.
Gyrininae is a subfamily of ground and water beetles in the family Gyrinidae. There are at least 740 described extant species in Gyrininae.
