''Oneirodes'' 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 ...

of is a genus of marine

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of sk ...

belonging to the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Oneirodidae, the dreamers, a family of deep sea

anglerfish The anglerfish are ray-finned fish in the order Lophiiformes (). Both the order's common name, common and scientific name comes from the characteristic mode of predation, in which a modified dorsal Fish fin#Ray-fins, fin ray acts as a Aggressiv ...

es. These predatory, deep-sea fishes are found around the world. This is the

type genus In biological taxonomy, the type genus (''genus typica'') is the genus which defines a biological family and the root of the family name. Zoological nomenclature According to the International Code of Zoological Nomenclature, "The name-bearin ...

, and the most speciose genus, of the family Oneirodidae. They are sexually dimorphic but, like most taxa within their family, the small males are free living and are not sexual parasites on the larger females. Only the females are used to identify the species in this genus as no species specific characters have been found for males.

Taxonomy

''Oneirodes'' was first proposed proposed as a

monospecific genus In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...

in 1871 by the Danish

zoologist Zoology ( , ) is the scientific study of animals. Its studies include the structure, embryology, classification, habits, and distribution of all animals, both living and extinct, and how they interact with their ecosystems. Zoology is one ...

and

naturalist Natural history is a domain of inquiry involving organisms, including animals, fungi, and plants, in their natural environment, leaning more towards observational than experimental methods of study. A person who studies natural history is cal ...

Christian Frederik Lütken Christian Frederik Lütken (; 7 October 1827, in Sorø – 6 February 1901), was a Danish zoologist and naturalist. In 1852, he resigned his commission as a lieutenant with the Danish army, and earned his master's degree in sciences the followi ...

when he described ''Oneirodes eschrichtii''. Lütken gave the type locality of ''O. eschrichtii'' as off the western coast of

Greenland Greenland is an autonomous territory in the Danish Realm, Kingdom of Denmark. It is by far the largest geographically of three constituent parts of the kingdom; the other two are metropolitan Denmark and the Faroe Islands. Citizens of Greenlan ...

. The 5th edition of

Fishes of the World ''Fishes of the World'' is a standard reference for the systematics of fishes. It was first written in 1976 by the American ichthyologist Joseph S. Nelson (1937–2011). Now in its fifth edition (2016), the work is a comprehensive overview of t ...

classifies this genus in the family Oneirodidae in the

suborder Order () is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized ...

Ceratioidei of the

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 ...

Lophiiformes The anglerfish are ray-finned fish in the order Lophiiformes (). Both the order's common and scientific name comes from the characteristic mode of predation, in which a modified dorsal fin ray acts as a lure for prey (akin to a human angler, ...

. Theodore Gill named the family Oneirodidae in 1878 with ''O. escherichtii'' as its only species, making ''Oneirodes'' the type genus of its family.

Etymology

''Oneirodes'' means "dream-like". Lütken did not explain this choice of name.

David Starr Jordan David Starr Jordan (January 19, 1851 – September 19, 1931) was the founding president of Stanford University, serving from 1891 to 1913. He was an ichthyologist during his research career. Prior to serving as president of Stanford Universi ...

and

Barton Warren Evermann Barton Warren Evermann (October 24, 1853 – September 27, 1932) was an American ichthyologist. Early life and education Evermann was born in Monroe County, Iowa in 1853. His family moved to Indiana while he was still a child and it was ...

suggested in 1898 that the name referred to the small, skin-covered eyes. Alternatively, in 2009,

Theodore Wells Pietsch III Theodore Wells Pietsch III (born March 6, 1945) is an American systematist and evolutionary biologist especially known for his studies of anglerfishes. Pietsch has described 72 species and 14 genera of fishes and published numerous scientific pa ...

proposed that the name was given because the fish is "so strange and marvelous that it could only be imagined in the dark of the night during a state of unconsciousness”.

Species

''Oneirodes'' is the most speciose genus in the family Oneirodidae and has the following species classified within it: * '' Oneirodes acanthias'' C. H. Gilbert, 1915 (Spiny dreamer) * '' Oneirodes alius'' Seigel & Pietsch, 1978 * '' Oneirodes amaokai'' H. C. Ho & Kawai, 2016 (Amaoka's dreamer) * '' Oneirodes anisacanthus'' Regan, 1925 * '' Oneirodes basili'' Pietsch, 1974 * '' Oneirodes bradburyae'' M. G. Grey, 1956 * '' Oneirodes bulbosus'' W. M. Chapman, 1939 * ''

Oneirodes carlsbergi ''Oneirodes carlsbergi'' is a species of deep-sea anglerfish in the family Oneirodidae, commonly known as the dreamers. This species inhabits the tropical eastern Atlantic and Pacific Oceans. Taxonomy ''Oneirodes carlsbergi'' was first formally ...

'' Regan & Trewavas, 1932 * '' Oneirodes clarkei''

Swinney Swinney may refer to: People *Dabo Swinney (born 1969), the head coach of the Clemson University Tigers football team * David Swinney (1946–2006), prominent psycholinguist *Harry Swinney (born 1939), American physicist noted for his contributions ...

& Pietsch, 1988 * '' Oneirodes cordifer''

Prokofiev Sergei Sergeyevich Prokofiev; alternative transliterations of his name include ''Sergey'' or ''Serge'', and ''Prokofief'', ''Prokofieff'', or ''Prokofyev''. , group=n ( – 5 March 1953) was a Russian composer, pianist, and conductor who l ...

, 2014Prokofiev, A.M. (2014): New and Rare Species of Deepsea Pelagic Fishes of Families Opisthoproctidae, Melanostomiidae, Oneirodidae, and Linophrynidae. ''Journal of Ichthyology, 54 (6): 377-383.'' * '' Oneirodes cristatus'' Regan & Trewavas, 1932 * '' Oneirodes dicromischus'' Pietsch, 1974 * '' Oneirodes epithales'' J. W. Orr, 1991 (Nightmare dreamer) * '' Oneirodes eschrichtii'' Lütken, 1871 (Bulbous dreamer) * '' Oneirodes flagellifer'' Regan & Trewavas, 1932 * '' Oneirodes formosanus'' H. C. Ho & K. T. Shao, 2019 * '' Oneirodes haplonema'' A. L. Stewart & Pietsch, 1998 * '' Oneirodes heteronema'' Regan & Trewavas, 1932 * '' Oneirodes kreffti'' Pietsch, 1974 (Krefft's dreamer) * '' Oneirodes luetkeni'' Regan, 1925 * '' Oneirodes macronema'' Regan & Trewavas, 1932 * '' Oneirodes macrosteus'' Pietsch, 1974 * '' Oneirodes melanocauda'' Bertelsen, 1951 * '' Oneirodes micronema'' Grobecker, 1978 * '' Oneirodes mirus'' Regan & Trewavas, 1932 * '' Oneirodes myrionemus'' Pietsch, 1974 * '' Oneirodes notius'' Pietsch, 1974 * '' Oneirodes parapietschi'' Prokofiev, 2014Prokofiev, A.M. (2014): New Species and New Records of Deepsea Anglerfish of the Family Oneirodidae. ''Journal of Ichthyology, 54 (8): 602-607.'' * '' Oneirodes pietschi'' H. C. Ho & K. T. Shao, 2004 * '' Oneirodes plagionema'' Pietsch & Seigel, 1980 * '' Oneirodes posti'' Bertelsen & Grobecker, 1980 * '' Oneirodes pterurus'' Pietsch & Seigel, 1980 * '' Oneirodes quadrinema'' H. C. Ho, Kawai & Amaoka, 2016 (Indonesian dreamer)Ho, H.-C., Kawai, T. & Amaoka, K. (2016): Records of deep-sea anglerfishes (Lophiiformes: Ceratioidei) from Indonesia, with descriptions of three new species. ''Zootaxa, 4121 (3): 267–294.'' * '' Oneirodes rosenblatti'' Pietsch, 1974 * '' Oneirodes sabex'' Pietsch & Seigel, 1980 (Rough dreamer) *'' Oneirodes sanjeevani'' Rajeeshkumar, 2017 * '' Oneirodes schistonema'' Pietsch & Seigel, 1980 * '' Oneirodes schmidti'' Regan & Trewavas, 1932 * '' Oneirodes sipharum'' Prokofiev, 2014 * '' Oneirodes theodoritissieri'' Belloc, 1938 * '' Oneirodes thompsoni'' L. P. Schultz, 1934 (Alaska dreamer) * '' Oneirodes thysanema'' Pietsch & Seigel, 1980 A fossil member of this genus was found from

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 ...

-aged deposits of

Sakhalin Island Sakhalin ( rus, Сахали́н, p=səxɐˈlʲin) is an island in Northeast Asia. Its north coast lies off the southeastern coast of Khabarovsk Krai in Russia, while its southern tip lies north of the Japanese island of Hokkaido. An islan ...

Characteristics

''Oneiriodes'' dreamers are characterised by having spines on the sphenotic bone, a deep incision on the rear edge of the operculum, and rod-shaped pelvic bones that are not expanded or expanded only slightly at the tips. The lobe of the

pectoral fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish aquatic locomotion, swim. Apart from the tail or caudal fin, fish fins have no direct connection with the vertebral column ...

is short and wide with the length of the lobe being less than that of the longest pelvic fin rays. There is a spine on the

symphysis A symphysis (, : symphyses) is a fibrocartilaginous fusion between two bones. It is a type of cartilaginous joint, specifically a secondary cartilaginous joint. # A symphysis is an amphiarthrosis, a slightly movable joint. # A growing together o ...

of the lower jaw and the lower margin of this symphysis is convex. The rays of the

caudal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only ...

have no internal pigmentation and the black skin on the caudal peduncle does not extend past the base of the caudal fin. The

illicium ''Illicium'' is a genus of flowering plants treated as part of the family Schisandraceae,

merges from between the

frontal bone In the human skull, the frontal bone or sincipital bone is an unpaired bone which consists of two portions.'' Gray's Anatomy'' (1918) These are the vertically oriented squamous part, and the horizontally oriented orbital part, making up the bo ...

s, the frontal bones are curved on their upper margin, and the subopercular bone is short and wide with a nearly circular lower part. There are 4, occasionally 5, soft rays in the

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

. A unique character of the metamorphosed females of ''Oneirodes'' is that the posterior end of the

pterygiophore A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine biology, marine environments, so the fins are not all Homology (biol ...

of the illicium emerges from the skin on the back, behind the head. The males have unpigmented skin between the nostrils, and the inner surface of the subopercle is also unpigmented. The caudal peduncle has no subdermal pigments, and there are between 7 and 13 denticles on the lower jaw. The females range in

standard length Fish measurement is the measuring of individual fish and various parts of fish anatomy, their anatomies, for data used in many areas of ichthyology, including Taxonomy (biology), taxonomy and fishery biology. Overall length Standard length (SL) is ...

from , and the published species descriptions are based on females as there are no known morphological character that separate the males by species. The males are free-living and non-parasitic. Male specimens measure between .

Distribution and habitat

''Oneirodes'' dreamers are found in the

Atlantic The Atlantic Ocean is the second largest of the world's five oceanic divisions, with an area of about . It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for se ...

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the cont ...

and Indian Oceans. They are

bathydemersal Demersal fish, also known as groundfish, live and feed on or near the bottom of ocean, seas or lakes (the demersal zone).Walrond Carl . "Coastal fish - Fish of the open sea floor"Te Ara - the Encyclopedia of New Zealand. Updated 2 March 2009 T ...

fishes found at depths between .

References

{{Authority control Oneirodidae Marine fish genera Taxa named by Christian Frederik Lütken