Macropinna

Macropinna
Illustration
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Argentiniformes
Family: Opisthoproctidae
Genus: Macropinna
W. M. Chapman, 1939
Species:
M. microstoma
Binomial name
Macropinna microstoma

The Pacific barreleye fish[1] (Macropinna) is a genus of ray-finned fish belonging to Opisthoproctidae, the barreleye family. It contains one species, M. microstoma. It is recognized for a highly unusual transparent, fluid-filled shield on its head, through which the lenses of its eyes can be seen. It was originally believed that the tubular eyes of this fish were fixed in place and, therefore, only provided a tunnel vision view of what was seen above its head. However, in 2008, scientists discovered that its eyes were able to rotate both up and forward in its transparent shield.[2][3] M. microstoma has a tiny mouth and most of its body is covered in large scales. The fish normally hangs nearly motionless in the water, at a depth of about 600 metres (2,000 ft) to 800 metres (2,600 ft), using its large fins for stability and with its eyes directed upward. In the low light conditions it is assumed the fish detects prey by its silhouette. This is because the eyes have no lens in the diverticulum, so images would most likely occur through reflection. Due to the eyes facing upwards, light is able to enter the eyes and through the illumination, silhouettes are formed. [4] MBARI researchers Bruce Robison and Kim Reisenbichler observed that when prey such as small fish and jellyfish are spotted, the eyes rotate like binoculars, facing forward as it turns its body from a horizontal to a vertical position to feed. Robison speculates that M. microstoma steals food from siphonophores.[5]

  1. ^ "Pacific Barreleye (Macropinna microstoma)". iNaturalist.
  2. ^ Robison, Bruce; Reisenbichler, Kim (2008). "Macropinna microstoma and the Paradox of Its Tubular Eyes". Copeia. Retrieved 26 March 2021.
  3. ^ LiveScience.com (23 February 2009). "Strange fish has a see-through head". NBC News. Retrieved 24 February 2009.
  4. ^ Robison, Bruce H.; Reisenbichler, Kim R. (18 December 2008). "Macropinna microstoma and the Paradox of Its Tubular Eyes". Copeia. 2008 (4): 780–784. doi:10.1643/CG-07-082. ISSN 0045-8511.
  5. ^ Fulton-Bennett, Kim (23 February 2009). "Researchers solve mystery of deep-sea fish with tubular eyes and transparent head". Retrieved 24 February 2009.