''Cystisoma '' is a
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
of
amphipod. It is the only member of the family Cystisomatidae within the
Hyperiidea.
The genus is noted for its nearly completely transparent body, adapted for life in low light waters.
Description
Gallery
''Cystisoma'' are characterized by unpigmented, transparent bodies which render them essentially invisible in water unless under precisely angled lighting.
Only their eyes are pigmented. There is only a single pair of eyes which are large and directed upwards, being spread into a thin sheet on the upper surface of the head. This is likely an adaption of life in the ocean depths, where the only major light source is from above.
Marine biologists at
Duke University and the
Smithsonian analyzed the crustacean's shell and discovered that it was covered in microscopic spheres that significantly reduce
reflected light, thus giving the organism an
antireflective coating. The spheres are believed to be
bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...
due to their morphology and method of reproduction. Minute structures called nanoprotuberances were also observed on the ''Cystisoma''
's body, notably on the organism's legs. Researchers believe that they act as a buffer between light and the
amphipod's body, significantly reducing surface reflection.
Size
''Cystisoma'' are the largest of
hyperiids, reaching lengths over 100 mm.
Distribution
''Cystisoma'' inhabit the dim
epipelagic
The photic zone, euphotic zone, epipelagic zone, or sunlight zone is the uppermost layer of a body of water that receives sunlight, allowing phytoplankton to perform photosynthesis. It undergoes a series of physical, chemical, and biological proc ...
and
mesopelagic
The mesopelagic zone (Greek μέσον, middle), also known as the middle pelagic or twilight zone, is the part of the pelagic zone that lies between the photic epipelagic and the aphotic bathypelagic zones. It is defined by light, and begins at ...
zones. They can be found in all of the world's oceans. They appear to be freely swimming organisms and unlike other hyperiids, do not appear to be closely associated with
salps
A salp (plural salps, also known colloquially as “sea grape”) or salpa (plural salpae or salpas) is a barrel-shaped, planktic tunicate. It moves by contracting, thereby pumping water through its gelatinous body, one of the most efficient ...
.
Species
* ''Cystisoma fabricii'' Stebbing, 1888
* ''Cystisoma gershwinae'' Zeidler, 2003
* ''Cystisoma latipes'' (Stephensen, 1918)
* ''Cystisoma longipes'' (Bovallius, 1886)
* ''Cystisoma magna'' (Woltereck, 1903)
* ''Cystisoma pellucida'' (Willemöes-Suhm, 1873)
References
External links
Cystisoma Eye
{{Taxonbar, from=Q10465209
Amphipoda
Crustaceans by year of formal description
Crustaceans described in 1842