Codlets are a family, Bregmacerotidae, of

cod Cod (: cod) is the common name for the demersal fish genus ''Gadus'', belonging to the family (biology), family Gadidae. Cod is also used as part of the common name for a number of other fish species, and one species that belongs to genus ''Gad ...

-like fishes, containing the single genus ''Bregmaceros'' found in

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

and

subtropical The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones immediately to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Ge ...

waters throughout the world. They are very small fishes and even the largest, ''B. lanceolatus'', reaches only in length.

Etymology

Their scientific name is from

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

''bregma'' meaning the top of the head, and ''keras'' meaning "horn"; this refers to their occipital ray (a spine emerging from the top of the head).

Fossil record

Fossils of ''Bregmaceros'' are found from the

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

to the

Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS), as well as the current and most recent of the twelve periods of the ...

(age range: from 37.2 to 0.0 million years ago.). They are known from various localities in

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

. A potential extinct relative, '' Bregmacerina'', is known from the Early Miocene of Russia, where it inhabited the

Paratethys The Paratethys sea, Paratethys ocean, Paratethys realm or just Paratethys (meaning "beside Tethys"), was a large shallow inland sea that covered much of mainland Europe and parts of western Asia during the middle to late Cenozoic, from the lat ...

. It shares close similarities to ''Bregmaceros'' in the reduction of the first dorsal fin, but differs in other aspects. It remains uncertain whether it is an actual member of the Bregmacerotidae.

Species

Currently, 17 species in this genus are recognized: * '' Bregmaceros anchovia'' Ho, Endo & Lee, 2020 (false anchovy codlet) * '' Bregmaceros arabicus'' D'Ancona & Cavinato, 1965 * '' Bregmaceros atlanticus'' Goode &

Bean A bean is the seed of some plants in the legume family (Fabaceae) used as a vegetable for human consumption or animal feed. The seeds are often preserved through drying (a ''pulse''), but fresh beans are also sold. Dried beans are traditi ...

, 1886 (antenna codlet) * '' Bregmaceros bathymaster'' D. S. Jordan & Bollman, 1890 (codlet) * '' Bregmaceros cantori'' Milliken & Houde, 1984 (striped codlet) * '' Bregmaceros cayorum'' Nichols, 1952 * '' Bregmaceros houdei'' Saksena & Richards, 1986 (stellate codlet) * '' Bregmaceros japonicus'' S. Tanaka (I), 1908 (Japanese codlet) * '' Bregmaceros lanceolatus'' S. C. Shen, 1960 * '' Bregmaceros mcclellandi'' W. Thompson, 1840 (spotted codlet, Macclelland's unicorn-cod, unicorn cod) * '' Bregmaceros moseri'' Harold & Baltzegar, 2023 (gyre codlet) * '' Bregmaceros nectabanus'' Whitley, 1941 (smallscale codlet) * '' Bregmaceros neonectabanus'' S. Masuda, Ozawa & Tabeta, 1986 * '' Bregmaceros pescadorus'' S. C. Shen, 1960 * '' Bregmaceros pseudolanceolatus''

Torii A is a traditional culture of Japan, Japanese gate most commonly found at the entrance of or within a Shinto shrine, where it symbolically marks the transition from the mundane to the sacred, and a spot where kami are welcomed and thought to ...

, Javonillo & Ozawa, 2004 (false lance codlet) * '' Bregmaceros rarisquamosus''

Munro A Munro (; ) is defined as a mountain in Scotland with a height over , and which is on the Scottish Mountaineering Club (SMC) official list of Munros; there is no explicit topographical prominence requirement. The best known Munro is Ben Nevi ...

, 1950 (big-eye unicorn-cod) * '' Bregmaceros retrodorsalis'' Ho & Endo, 2020 (back-fin codlet)

References

* Bregmacerotidae {{Gadiformes-stub