Spercheus is a genus of aquatic beetles which are placed in a family of their own, Spercheidae within the Hydrophiloidea. About 20 species are known from around the world except the Nearctic with the majority being from the Oriental and Afrotropical Realms.
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.
Amphizoa is a genus of aquatic beetles in the suborder Adephaga, placed in its own monogeneric family, Amphizoidae. There are five known species of Amphizoa, three in western North America and two in the eastern Palearctic. They are sometimes referred to by the common name troutstream beetles.
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.
Hydrophilidae, also known colloquially as water scavenger beetles, is a family of beetles. Aquatic hydrophilids are notable for their long maxillary palps, which are longer than their antennae. Several of the former subfamilies of Hydrophilidae have recently been removed and elevated to family rank; Epimetopidae, Georissidae, Helophoridae, Hydrochidae, and Spercheidae. While the majority of hydrophilids are aquatic, around a third of described species are terrestrial, mostly belonging to the subfamily Sphaeridiinae.
Myxophaga is the second-smallest suborder of the Coleoptera after Archostemata, consisting of roughly 65 species of small to minute beetles in four families. The members of this suborder are aquatic and semiaquatic, and feed on algae.
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.
Copelatus is a large genus of small diving beetles. There are some 470 described species in the genus, found worldwide, but they are most diverse in tropical South America, Africa and South-East Asia. Copelatus are often black or brown in color, many species of Copelatus possessing visible longitudinal furrows down the dorsal side of the wings of both sexes.
Polyura is a subgenus of butterflies also referred to as Nawab butterflies and belonging to the brush-footed butterfly subfamily Charaxinae, or leafwing butterflies. Like the large and conspicuous forest queens, they belong to the genus Charaxes, unique genus of the tribe Charaxini.
Rhantus is a genus of beetle in family Dytiscidae. There are about 100 species distributed worldwide. They often live in pools and marshy habitat types. Several species have colonized oceanic islands and become endemics.
Hygrobia is a genus of aquatic beetles native to Europe, North Africa, China and Australia. It is the only genus in the family Hygrobiidae, also known as the Paelobiidae. These are known commonly as squeak beetles or screech-beetles.
Xianshanosaurus is a genus of sauropod dinosaur from the Early Cretaceous (Aptian-Albian) of the Ruyang Basin in Henan Province, China. Its type and only species is Xianshanosaurus shijiagouensis. It was described in 2009 by a team of paleontologists led by Lü Junchang. Xianshanosaurus may be a titanosaur, and Daxiatitan may be its closest relative, but its evolutionary relationships remain controversial.
Helochares is a genus of water scavenger beetles in the family Hydrophilidae, represented by 161 described species. It is distributed across the Afrotropical, Australasian, Indo-Malayan, Nearctic, and Palearctic realms.
Carabdytes plantaris is a naturally uncommon species of diving beetle in the family Dytiscidae. It is endemic to New Zealand. For over a century, it was known from just a single specimen collected in 1880 "near Dunedin", and doubts were cast on whether it was actually a New Zealand species at all. In 1986, it was rediscovered when several were collected from a roadside pond near Lake Ellesmere. Carabdytes plantaris is now classed as "naturally uncommon" by the Department of Conservation.
Gyrininae is a subfamily of ground and water beetles in the family Gyrinidae. There are at least 740 described extant species in Gyrininae.
Eretes sticticus, the western erete, is a species of predaceous diving beetle in the family Dytiscidae. It is found in Africa, the Middle East, and the Americas from the southern United States to Peru. This species preys specifically on mosquito larvae in ponds and pools. They can kill up to all the instar larvae of the mosquito depending on size and density of the prey.
Aspidytidae is a family of aquatic beetles of the suborder Adephaga, described in 2002 from specimens in South Africa and China. There are only two known species in the family and these were originally described in the genus Aspidytes, but later the new genus Sinaspidytes was erected for the species found in China. The family can also be referred to by its trivial name cliff water beetles.
Sinaspidytes is a genus of aquatic beetles in Aspidytidae, first recorded in 2003 from specimens in the Shaanxi province, China. It is monotypic, with the only species being Sinaspidytes wrasei. Originally this species was placed in the genus Aspidytes with a second species from South Africa, but was later transferred to Sinaspidytes. The genus contains the single species S. wrasei. The aquatic beetle is 4.8 - 5.2 mm long and lives in hygropetric habitats.
