''Spercheus'' is a genus of aquatic beetles which are placed in a family of their own, Spercheidae within the

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 ...

. About 20 species are known from around the world except the

Nearctic The Nearctic realm is one of the eight biogeographic realms constituting the Earth's land surface. The Nearctic realm covers most of North America, including Greenland, Central Florida, and the highlands of Mexico. The parts of North America t ...

with the majority being from the

Oriental The Orient is a term for the East in relation to Europe, traditionally comprising anything belonging to the Eastern world. It is the antonym of ''Occident'', the Western World. In English, it is largely a metonym for, and coterminous with, the ...

and

Afrotropical The Afrotropical realm is one of Earth's eight biogeographic realms. It includes Africa south of the Sahara Desert, the majority of the Arabian Peninsula, the island of Madagascar, southern Iran and extreme southwestern Pakistan, and the island ...

Realms. All life stages are found in shallow still water with rich vegetation, which in some species includes temporary saline pools. Adults and larvae live attached to pieces of vegetation or debris, and also walk on the underside of the water surface. Air is held in a bubble on the underside of the body. The larvae feed on grazed detritus as well as drifting algae, dead organsims, and other organic refuse. The adults live as

filter feeder Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ...

s on floating debris like decaying plant material and other decomposing organic remains. The adult females build a silken-egg case which they attach to their mid-tibiae and held by the hind legs, carried below the abdomen. These beetles were formerly placed in the family

Hydrophilidae 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 ...

but are distinctive. The front of the head is notched and the 7–9 segmented antenna has the terminal 3–4 segments club like and an enlarged fourth segment. The elytra are very convex and one or two abdominal segments extend beyond the apex. They have 5 tarsal segments on all legs. Possible fossils of ''Spercheus'' have been described from the

Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...

aged

Bembridge Marls The Bouldnor Formation is a geological formation in the Hampshire Basin of southern England. It is the youngest formation of the Solent Group and was deposited during the uppermost Eocene and lower Oligocene. Stratotype and occurrence The Boul ...

of the Isle of Wight, England. The extinct genus '' Prospercheus'' from the Late

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...

of Shar-Teg, Mongolia, has also been considered a close relative of ''Spercheus'', and also placed in Spercheidae.

Species

* ''Spercheus belli'' ** ''Spercheus belli babylonicus'' * ''Spercheus burgeoni'' * ''Spercheus cerisyi'' * ''Spercheus crenulatus'' * ''Spercheus emarginatus'' * ''Spercheus fimbriicollis'' * ''Spercheus gerardi'' * ''Spercheus halophilus'' * ''Spercheus hanseni'' * ''Spercheus hovanus'' * ''Spercheus humeralis'' * ''Spercheus platycephalus'' ** ''Spercheus platycephalus interruptus'' * ''Spercheus senegalensis'' * ''Spercheus siamensis'' * ''Spercheus spangleri'' * ''Spercheus stangli'' * ''Spercheus stasimus'' * ''Spercheus wattsi''

References

External links

Australian Freshwater Invertebrates

Tree of Life
{{taxonbar, from=Q18113956, from2=Q755568 Hydrophiloidea Polyphaga genera