Codlets are a family, Bregmacerotidae, of cod-like fishes, containing the single genus Bregmaceros found in tropical and subtropical waters throughout the world. They are very small fishes, and even the largest, B. lanceolatus, reaches only in length.
The codlets appear to be sister to all remaining Gadiformes lineages, even when attempting to account for possible long branch attraction. They are the only member of the suborder Bregmacerotoidei.
Etymology
Their scientific name is from Greek 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).
Species
Currently, 17 species in this genus are recognized:
- Bregmaceros anchovia <small>Ho, Endo & Lee, 2020</small> (false anchovy codlet)
- Bregmaceros arabicus <small>D'Ancona & Cavinato, 1965</small>
- Bregmaceros atlanticus <small>Goode & Bean, 1886</small> (antenna codlet)
- Bregmaceros bathymaster <small>D. S. Jordan & Bollman, 1890</small> (codlet)
- Bregmaceros cantori <small>Milliken & Houde, 1984</small> (striped codlet)
- Bregmaceros cayorum <small>Nichols, 1952</small>
- Bregmaceros houdei <small>Saksena & Richards, 1986</small> (stellate codlet)
- Bregmaceros japonicus <small>S. Tanaka (I), 1908</small> (Japanese codlet)
- Bregmaceros lanceolatus <small>S. C. Shen, 1960</small>
- Bregmaceros mcclellandi <small>W. Thompson, 1840</small> (spotted codlet, Macclelland's unicorn-cod, unicorn cod)
- Bregmaceros moseri <small>Harold & Baltzegar, 2023</small> (gyre codlet)
- Bregmaceros nectabanus <small>Whitley, 1941</small> (smallscale codlet)
- Bregmaceros neonectabanus <small>S. Masuda, Ozawa & Tabeta, 1986</small>
- Bregmaceros pescadorus <small>S. C. Shen, 1960</small>
- Bregmaceros pseudolanceolatus <small>Torii, Javonillo & Ozawa, 2004</small> (false lance codlet)
- Bregmaceros rarisquamosus <small>Munro, 1950</small> (big-eye unicorn-cod)
- Bregmaceros retrodorsalis <small>Ho & Endo, 2020</small> (back-fin codlet)
Fossil species
Fossils of Bregmaceros are found from the Eocene to the Quaternary (age range: from 37.2 to 0.0 million years ago). They are known from various localities in Europe, North America, Africa, and Australasia. A few are known from articulated fossils' skeletons, but a vast majority of fossil bregmacerotid remains are only from isolated, diagnostic otoliths. About 14 fossil Bregmaceros species are known, with two from articulated skeletons and 12 known from otoliths:
- â Bregmaceros albyi <small>(Sauvage, 1880)</small> (B. bosniaski <small>(Sauvage, 1880)</small>) - Miocene of Spain, Portugal, Italy, Algeria, Gabon, Greece, Malta, Austria, Poland, the Czech Republic & the eastern United States, and Pliocene of Spain, Italy & Greece. Known from both fossil skeletons and isolated otoliths.
- â Bregmaceros antiquus <small>Schwarzhans, 1980</small> - late Eocene of New Zealand [otolith]
- â Bregmaceros brihandensis <small>Nolf, 1988</small> - late Eocene of France & Italy [otolith]
- â Bregmaceros catulus <small>(Schubert, 1908)</small> - early Oligocene of the Czech Republic [otolith]
- â Bregmaceros deklaszi <small>Schwarzhans, 2013</small> - Oligocene of France, early Miocene of Italy, mid-late Miocene of Gabon [otolith]
- â Bregmaceros felkeri <small>Schwarzhans, 2007</small> - middle Eocene of Germany [otolith]
- â Bregmaceros filamentosus <small>(Priem, 1908)</small> - mid-late Eocene of Georgia & Iran, Oligocene of Poland, Romania & North Caucasus (Russia), potentially Miocene of Egypt & the Czech Republic. Known from fossil skeletons and isolated otoliths.
- â Bregmaceros hybridus <small>Schwarzhans, 2013</small> - early Miocene of Italy, early-mid Miocene of Spain, mid-late Miocene of Gabon [otolith]
- â Bregmaceros luellingensis <small>Schwarzhans</small> <small>& Wienrich, 2009</small> - early Miocene of Mexico, middle Miocene of Germany [otolith]
- â Bregmaceros minimus <small>(Frost, 1934)</small> - middle Eocene of England, late Eocene of Ukraine [otolith]
- â Bregmaceros minutus <small>Stinton, 1958</small> - middle Miocene of South Australia [otolith]
- â Bregmaceros oblongus <small>Schwarzhans, 1977</small> - early Oligocene of Germany [otolith]
- â Bregmaceros prosoponos <small>Grenfell, 1984</small> - early Miocene of New Zealand [otolith]
- â Bregmaceros troelli <small>Dante</small> <small>& Frizzell, 1965</small> - middle Eocene of Texas, US [otolith]
A potential extinct relative, Bregmacerina, is known from the Early Miocene of Russia, where it inhabited the Paratethys. 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.
References