Ghost fish

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Ghost fish
Opisthoproctus soleatus

Opisthoproctus soleatus

Systematics
Subclass : Neuflosser (Neopterygii)
Subclass : Real bony fish (Teleostei)
Overcohort : Clupeocephala
Cohort : Euteleosteomorpha
Order : Golden salmon (Argentiniformes)
Family : Ghost fish
Scientific name
Opisthoproctidae
Jordan , 1923

The barreleye (Opisthoproctidae from Greek οπισθή. Opisthe behind 'and πρωκτός proctos , anus ), also high-watchers called, are one of 20 species existing family of world living deep-sea fishing .

features

Ghost fish have a squat and laterally flattened or elongated, almost cylindrical body and reach standard lengths of 6 to 50 cm. Bathylychnops exilis is the largest species with a maximum length of 50 centimeters. Its relatives remain significantly smaller with less than 20 centimeters. The genera Opisthoproctus and Macropinna have rather tall bodies, while Rhynchohyalus , Winteria , Dolichopteryx and Bathylychnops are rather slender. The color of the body is usually a dark brown, the top of the head is often transparent. In contrast to other deep-sea fish, the toothless, terminal mouth is only small and, in most species, pointed. The premaxillary is reduced or absent. The maxilla is toothless, the vomer is dentate, on the palatine bone and the dental teeth may be present or absent. The scales are large, cycloid, and easily fall off. All species, except for those of the genus Dolichopteryx , whose pelvic fins are wing-like elongated and reach half the body length, have only small fins. All fins are without spines. The pectoral fins are set deep on the sides of the body and have 9 to 20 fin rays . The dorsal fin is located in the back of the body and is supported by 8 to 16 fin rays, the anal fin lies behind it and has 8 to 14 fin rays. The narrow pelvic fins are often elongated. They lie below or just a little in front of the dorsal fin and have 7 to 12 fin rays. The sideline is interrupted, extends along the middle of the flank and does not extend to the caudal fin. Some barreleye have an adipose fin and light organs not others. The swim bladder is missing most. The number of Branchiostegal rays is from two to four, that of the vertebrae from 31 to 84. Behind the fourth branchial arch, the Opisthoproctidae, like many other species of the Argentiniformes, have a small, bag-like organ that is associated with the planktonic diet of the fish .

Ghostfish are noticeable for their tubular, upward-pointing eyes. The distance between the eyes is small. They are adapted to life in the deep sea thanks to a large lens and a retina with an exceptionally high number of rods and a high density of the red visual pigment rhodopsin . There are no cones . With Winteria , the eyes are more directed forward. Macropinna microstoma has movable eyes under a transparent cover that covers the upper part of the head, so that it can also look forward.

The genera Dolichopteryx , Opisthoproctus , and Winteria have light organs in which the bioluminescent bacterium Photobacterium phosphoreum (family Vibrionaceae ) provides a weak light. The light organs of Dolichopteryx and Opisthoproctus can serve as camouflage. The fish are enveloped by diffuse light so that they are not seen from below in the light coming from above.

habitat

Ghost fish inhabit, presumably solitary, the mean depths of 400 to 2500 meters. Unlike other animals living at greater depths, they do not take part in the daily vertical migration , but always stay in the dark zone. Their adapted eyes enable them to track down their prey consisting of zooplankton here too . The distribution of the species corresponds to the isotherms of the oceans, so the habitat of Opisthoproctus soleatus is limited by the 400-meter isotherm for 8 ° C.

Reproduction

High-gazers spawn pelagically , their eggs and larvae float with the ocean currents even in less deep regions of the ocean. After the metamorphosis to the adult form, they move back into the deeper water. The species of the genus Dolichopteryx do not undergo metamorphosis and retain larval properties even in adulthood ( neoteny ).

Genera and species

There are 20 species in nine genera:

Bathylychnops exilis
Dolichopteryx longipes
Monacoa grimaldii
Winteria telescopa

literature

  • William N. Eschmeyer, Earl S. Herald, Howard Hamann: A field guide to Pacific Coast Fishes of North America. From the Gulf of Alaska to Baja California (Peterson Field Guides; 28). Houghton Mifflin, Boston, Mass. 1983, ISBN 0-395-33188-9 .
  • Joseph S. Nelson : Fishes of the World. 4th edition. John Wiley & Sons, Hoboken NJ et al. 2006, ISBN 0-471-25031-7 .
  • JR Paxton & DM Cohen: Barreleyes, Opisthoproctidae. Page 1887 - in Kent E. Carpenter & Volker H. Niem: The Living Marine Resources of the Western Central Pacific. Volume 3. Batoid fishes, chimaeras and Bony fishes part 1 (Elopidae to Linophrynidae). Rome, FAO. 1998, ISBN 92-5-104302-7 .

Individual evidence

  1. Researchers solve mystery of deep-sea fish with tubular eyes and transparent head , Monterey Bay Aquarium Research Institute News Release, February 23, 2009
  2. Poulsen, JY, Sado, T., Hahn, C., Byrkjedal, I., Moku, M. & Miya, M. (2016): Preservation Obscures Pelagic Deep-Sea Fish Diversity: Doubling the Number of Sole-Bearing Opisthoproctids and Resurrection of the Genus Monacoa (Opisthoproctidae, Argentiniformes). PLoS ONE, 11 (8): e0159762. doi: 10.1371 / journal.pone.0159762

Web links

Commons : Ghost Fish  - Collection of images, videos and audio files