The redmouth whalefishes are two

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of deep-sea

whalefish The Cetomimiformes or whalefishes are an order of small, deep-sea ray-finned fish. Some authoritiesE.g. Nelson (2006) include the whalefishes as part of the order Stephanoberyciformes, within the superfamily Cetomimoidea. Their sister order, the ...

es in the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

''Rondeletia'', the only genus in the family Rondeletiidae. They are apparently close to the velvet whalefish (''Barbourisia rufa''), and apparently also to the

gibberfish The Gibberichthyidae, also known as gibberfishes, are a small family of deep sea stephanoberyciform fish, containing a single genus, ''Gibberichthys'' (from the Latin ''gibba'', "humpbacked" and the Greek ''ichthys'', "fish"), and two species. F ...

es (Gibberichthyidae). The latter and the Rondeletiidae are the only known living fishes which have the mysterious Tominaga's organ. Like the plant genus of the same name, this genus is named after

Guillaume Rondelet Guillaume Rondelet (27 September 150730 July 1566), also known as Rondeletus/Rondeletius, was Regius professor of medicine at the University of Montpellier in southern France and Chancellor of the University between 1556 and his death in 1566. He ...

. Redmouth whalefishes are small fishes. ''Rondeletia bicolor'' grows to about 6 cm long or so. It is most commonly found in the northern

Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...

, but has been documented from the eastern Pacific, as well, and presumably also occurs in the rest of the Atlantic. The better-known ''Rondeletia loricata'' is known from all oceans between 47°N–47°S; it has been recorded to reach a length of more than 9 cm when adult. Usually found in deep waters of tropical and temperate oceans around the world, down to 3,000 m or more, they make migrations up to shallower waters (around 100 m) at night to feed on

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

s and

amphipod Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods range in size from and are mostly detritivores or scavengers. There are more than 9,900 amphipod species so far descr ...

s. The

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

e occur in the surface waters, down to 50 m; previous to the onset of metamorphosis, they can be found in the uppermost few meters, descending as they mature.

Notochord In anatomy, the notochord is a flexible rod which is similar in structure to the stiffer cartilage. If a species has a notochord at any stage of its life cycle (along with 4 other features), it is, by definition, a chordate. The notochord consis ...

flexion occurs at around 4 mm

standard length Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish m ...

in ''R. loricata''.

Species

The currently recognized species in this genus are: * ''

Rondeletia bicolor ''Rondeletia bicolor'' is a species of redmouth whalefish known only from the western Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surf ...

'' (

Goode Goode ( or , depending on family) is a surname. Notable people Notable people with the surname include: * Alex Goode (Born 1988), British rugby union player * Alexander D. Goode (1911-1943), US Army chaplain * Andy Goode (born 1980), British ru ...

Bean A bean is the seed of several plants in the family Fabaceae, which are used as vegetables for human or animal food. They can be cooked in many different ways, including boiling, frying, and baking, and are used in many traditional dishes th ...

, 1895) * ''

Rondeletia loricata ''Rondeletia loricata'' is a species of redmouth whalefish The redmouth whalefishes are two species of deep-sea whalefishes in the genus ''Rondeletia'', the only genus in the family Rondeletiidae. They are apparently close to the velvet whal ...

'' ( T. Abe & Hotta, 1963)

References

External links

* * {{Taxonbar, from=Q2167047 Cetomimiformes