Argyropelecus
Encyclopedia
Argyropelecus is an ocean
ic ray-finned fish genus
which belongs in the family
Sternoptychidae
. A collective name is "silver hatchetfish
es", but this can also refer to a species
of the freshwater hatchetfish
es which are not particularly closely related but merely convergent
. The large pupil
s of these marine hatchetfishes enable them to see dim objects in the deep sea
, where light barely penetrates.
are placed in Argyropelecus:
Fossil
s of this genus show that they have existed at least since the mid-late Eocene
, about 40 million years ago.
Ocean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...
ic ray-finned fish genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
which belongs in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Sternoptychidae
Sternoptychidae
The marine hatchetfishes or deep-sea hatchetfishes as well as the related bottlelights, pearlsides and constellationfishes are small deep-sea bathypelagic ray-finned fish of the stomiiform family Sternoptychidae...
. A collective name is "silver hatchetfish
Silver hatchetfish
Silver hatchetfish may refer to:* Marine hatchetfishes of the genus Argyropelecus* The freshwater hatchetfish species Gasteropelecus levis...
es", but this can also refer to a species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of the freshwater hatchetfish
Freshwater hatchetfish
The freshwater hatchetfishes are a family, Gasteropelecidae, of ray-finned fish. The common hatchetfish is the most popular member among fish keeping hobbyists...
es which are not particularly closely related but merely convergent
Convergent evolution
Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, both birds and bats do, and are capable of powered flight. The wings are...
. The large pupil
Pupil
The pupil is a hole located in the center of the iris of the eye that allows light to enter the retina. It appears black because most of the light entering the pupil is absorbed by the tissues inside the eye. In humans the pupil is round, but other species, such as some cats, have slit pupils. In...
s of these marine hatchetfishes enable them to see dim objects in the deep sea
Deep sea
The deep sea, or deep layer, is the lowest layer in the ocean, existing below the thermocline and above the seabed, at a depth of 1000 fathoms or more. Little or no light penetrates this part of the ocean and most of the organisms that live there rely for subsistence on falling organic matter...
, where light barely penetrates.
Species
Seven living speciesSpecies
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
are placed in Argyropelecus:
- Argyropelecus aculeatusArgyropelecus aculeatusThe Lovely Hatchetfish or Atlantic Silver Hatchetfish is a species of fish in the Sternoptychidae family.-Further reading:...
– Lovely Hatchetfish, Atlantic Silver Hatchetfish - Argyropelecus affinis Garman, 1899 – Pacific Hatchetfish
- Argyropelecus gigas – Giant HatchetfishGiant hatchetfishThe Giant Hatchetfish or Greater Silver Hatchetfish a marine hatchetfish of the genus Argyropelecus, is found in every ocean except the north Pacific in deep tropical and subtropical waters.-References:...
, Greater Silver Hatchetfish - Argyropelecus hemigymnus – Half-naked HatchetfishHalf-naked hatchetfishArgyropelecus hemigymnus, the half-naked hatchetfish, short silver hatchetfish or spurred hatchetfish, is a deep-sea hatchetfish of the genus Argyropelecus found in deep tropical and subtropical waters of all oceans. It grows to a length of ....
, Short Silver Hatchetfish, Spurred Hatchetfish - Argyropelecus lychnus Garman, 1899 – Tropical Hatchetfish
- Argyropelecus olfersi (Cuvier, 1829)
- Argyropelecus sladeni Regan, 1908 – Sladen's Hatchetfish, Silvery Hatchetfish
Fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s of this genus show that they have existed at least since the mid-late Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
, about 40 million years ago.