''Gelyella'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...

copepod Copepods (; meaning 'oar-feet') are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (living in the water column), some are benthos, benthic (living on the sedimen ...

s. They live in

groundwater Groundwater is the water present beneath Earth's surface in rock and Pore space in soil, soil pore spaces and in the fractures of stratum, rock formations. About 30 percent of all readily available fresh water in the world is groundwater. A unit ...

karst Karst () is a topography formed from the dissolution of soluble carbonate rocks such as limestone and Dolomite (rock), dolomite. It is characterized by features like poljes above and drainage systems with sinkholes and caves underground. Ther ...

ic areas of southern France and western Switzerland. The two species are the only members of the family Gelyellidae and, although previously placed in the order

Harpacticoida Harpacticoida is an Order (biology), order of copepods, in the subphylum Crustacean, Crustacea. This order comprises 463 genus, genera and about 3,000 species; its members are benthic copepods found throughout the world in the marine environment ...

, a new

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

, Gelyelloida, was erected for this family alone. ''Gelyella'' shows some

paedomorphosis Neoteny (), also called juvenilization,Montagu, A. (1989). Growing Young. Bergin & Garvey: CT. is the delaying or slowing of the Physiology, physiological, or Somatic (biology), somatic, development of an organism, typically an animal. Neoteny i ...

, in which animals reach

sexual maturity Sexual maturity is the capability of an organism to reproduce. In humans, it is related to both puberty and adulthood. ''Puberty'' is the biological process of sexual maturation, while ''adulthood'', the condition of being socially recognized ...

while still partly resembling juveniles. The adults are long with a nearly cylindrical body that tapers towards the rear. There are eleven body segments, the last of which is the length of the previous two segments combined. Gorges areuse

Species

The first species of ''Gelyella'' was described in 1977 from material collected at

Saint-Gély-du-Fesc Saint-Gély-du-Fesc (; or ) is a Communes of France, commune in the Departments of France, department of Hérault, Occitania (administrative region), Occitania, southern France. The origin of this city is from Saint Gilles, a Christian of the 8 ...

Hérault Hérault (; , ) is a departments of France, department of the Regions of France, region of Occitania (administrative region), Occitania, Southern France. Named after the Hérault (river), Hérault River, its Prefectures in France, prefecture is M ...

, France and given the name ''Gelyella droguei''. A second species was later collected from the Gorges de l'Areuse in the

Swiss Jura Swiss most commonly refers to: * the adjectival form of Switzerland *Swiss people Swiss may also refer to: Places * Swiss, Missouri * Swiss, North Carolina * Swiss, West Virginia * Swiss, Wisconsin Other uses * Swiss Café, an old café located ...

, and named ''Gelyella monardi'' to mark the centenary of the birth of the Swiss naturalist Albert Monard. It is thought that the two species may have begun to diverge from a marine

common ancestor Common descent is a concept in evolutionary biology applicable when one species is the ancestor of two or more species later in time. According to modern evolutionary biology, all living beings could be descendants of a unique ancestor commonl ...

following the changes in coastline during the

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

. During the Miocene, the

Mediterranean Sea The Mediterranean Sea ( ) is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean basin and almost completely enclosed by land: on the east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern Eur ...

reached parts of Switzerland, but this was followed by the

Messinian salinity crisis In the Messinian salinity crisis (also referred to as the Messinian event, and in its latest stage as the Lago Mare event) the Mediterranean Sea went into a cycle of partial or nearly complete desiccation (drying-up) throughout the latter part of ...

, in which the sea almost dried up, leaving

salt lake A salt lake or saline lake is a landlocked body of water that has a concentration of salts (typically sodium chloride) and other dissolved minerals significantly higher than most lakes (often defined as at least three grams of salt per liter). I ...

s in the Mediterranean Basin.

References

External links

* {{Taxonbar, from1=Q2065539, from2=Q18710367, from3=Q18710371 Copepod genera Copepods