Oneirodes is a genus of is a genus of marine Actinopterygii belonging to the family Oneirodidae, the dreamers, a family of deep sea . These predatory, deep-sea fishes are found around the world. This is the type genus, 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 1871 by the Danish
zoologist and
naturalist Christian Frederik Lütken when he described
Oneirodes eschrichtii.
Lütken gave the type locality of
O. eschrichtii as off the western coast of
Greenland.
The 5th edition of Fishes of the World classifies this genus in the family Oneirodidae in the
suborder Ceratioidei of the
anglerfish order
Lophiiformes.
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 and Barton Warren Evermann suggested in 1898 that the name referred to the small, skin-covered eyes. Alternatively, in 2009, Theodore Wells Pietsch III 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:
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Oneirodes acanthias C. H. Gilbert, 1915 (Spiny dreamer)
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Oneirodes alius Seigel & Pietsch, 1978
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Oneirodes amaokai Ho Hsuan-Ching & Toshio Kawai, 2016 (Amaoka's dreamer)
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]
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Oneirodes anisacanthus Regan, 1925
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Oneirodes basili Pietsch, 1974
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Oneirodes bradburyae M. G. Grey, 1956
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Oneirodes bulbosus W. M. Chapman, 1939
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Oneirodes carlsbergi Regan & Trewavas, 1932
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Oneirodes clarkei Swinney & Pietsch, 1988
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Oneirodes cordifer Prokofiev, 2014
[Prokofiev, 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.]
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Oneirodes cristatus Regan & Trewavas, 1932
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Oneirodes dicromischus Pietsch, 1974
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Oneirodes epithales J. W. Orr, 1991 (Nightmare dreamer)
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Oneirodes eschrichtii Lütken, 1871 (Bulbous dreamer)
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Oneirodes flagellifer Regan & Trewavas, 1932
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Oneirodes formosanus H. C. Ho & Shao Kwang-Tsao, 2019
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Oneirodes haplonema A. L. Stewart & Pietsch, 1998
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Oneirodes heteronema Regan & Trewavas, 1932
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Oneirodes kreffti Pietsch, 1974 (Krefft's dreamer)
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Oneirodes luetkeni Regan, 1925
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Oneirodes macronema Regan & Trewavas, 1932
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Oneirodes macrosteus Pietsch, 1974
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Oneirodes melanocauda Erik Bertelsen, 1951
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Oneirodes micronema Grobecker, 1978
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Oneirodes mirus Regan & Trewavas, 1932
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Oneirodes myrionemus Pietsch, 1974
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Oneirodes notius Pietsch, 1974
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Oneirodes parapietschi Prokofiev, 2014
[Prokofiev, A.M. (2014): New Species and New Records of Deepsea Anglerfish of the Family Oneirodidae. Journal of Ichthyology, 54 (8): 602-607.]
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Oneirodes pietschi H. C. Ho & K. T. Shao, 2004
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Oneirodes plagionema Pietsch & Seigel, 1980
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Oneirodes posti Bertelsen & Grobecker, 1980
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Oneirodes pterurus Pietsch & Seigel, 1980
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Oneirodes quadrinema H. C. Ho, Kawai & Kunio 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.]
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Oneirodes rosenblatti Pietsch, 1974
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Oneirodes sabex Pietsch & Seigel, 1980 (Rough dreamer)
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Oneirodes sanjeevani Rajeeshkumar, 2017
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Oneirodes schistonema Pietsch & Seigel, 1980
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Oneirodes schmidti Regan & Trewavas, 1932
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Oneirodes sipharum Prokofiev, 2014
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Oneirodes theodoritissieri Belloc, 1938
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Oneirodes thompsoni L. P. Schultz, 1934 (Alaska dreamer)
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Oneirodes thysanema Pietsch & Seigel, 1980
A fossil member of this genus was found from Miocene-aged deposits of Sakhalin Island.
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 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 of the lower jaw and the lower margin of this symphysis is convex. The rays of the
caudal fin have no internal pigmentation and the black skin on the caudal peduncle does not extend past the base of the caudal fin. The illicium merges from between the
, 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.
A unique character of the metamorphosed females of
Oneirodes is that the posterior end of the
pterygiophore 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 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 .
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Distribution and habitat
Oneirodes dreamers are found in the Atlantic Ocean, Pacific Ocean and Indian Ocean Oceans. They are bathydemersal fishes found at depths between .
