''Vitreledonella richardi'', also known as the glass octopus, is an incirrate

octopus An octopus ( : octopuses or octopodes, see below for variants) is a soft-bodied, eight- limbed mollusc of the order Octopoda (, ). The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlefis ...

. It is in the

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 n ...

Vitreledonella ''Vitreledonella'' is a genus of mesopelagic octopods from the family Amphitretidae which contains two species, one of which is the glass octopus. These octopods have the sucker on their arms arranged in a single series with the suckers widely ...

'' and of the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Amphitretidae Amphitretidae is a family of mesopelagic octopods which contains three subfamilies, formerly classified as families in their own right. It is classified in the superfamily Octopodoidea. Species in the family Amphipetridae are characterised by ...

Description

''Vitreledonella richardi'' is a transparent, gelatinous, and almost colorless

meso- A meso compound or meso isomer is a non-optically active member of a set of stereoisomers, at least two of which are optically active. This means that despite containing two or more stereocenters, the molecule is not chiral. A meso compound is "sup ...

bathypelagic The bathypelagic zone or bathyal zone (from Greek βαθύς (bathýs), deep) is the part of the open ocean that extends from a depth of below the ocean surface. It lies between the mesopelagic above, and the abyssopelagic below. The bathypelag ...

octopod found worldwide in tropical and subtropical seas with a mantle length up to and a total length up to in adults. The upper three pairs of arms are subequal in length; in juveniles about as long as the mantle, in adults two to three times mantle length. The fourth, ventral pair is slightly shorter. Suckers are small, widely separated, and in a single series. In males, the left arm III is hectocotylized, with a spherical vesicle near the tip, but is not detachable. The large

ampulla An ampulla (; ) was, in Ancient Rome, a small round vessel, usually made of glass and with two handles, used for sacred purposes. The word is used of these in archaeology, and of later flasks, often handle-less and much flatter, for holy water or ...

and the elongate accessory gland lie out among the internal reproductive organs, notable among mature males alongside its reproductive anatomical counterparts. Its eyes are rectangular, as seen from the side. In accordance to its eyes; Two ''Vitreledonella richardi'' specimens obtained at 200 m in the

North Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the "Old World" of Africa, Europe and ...

were used to characterize the elongated eye. It is demonstrated that the cylindrical design, with the lens centered, results in a restricted horizontal field of vision. The unique

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology), study of the shapes or forms of artifacts *Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...

is thought to be an adaptation that reduces the eye's silhouette when viewed from below, and is part of the animal's

camouflage Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the b ...

technique. The

radula The radula (, ; plural radulae or radulas) is an anatomical structure used by molluscs for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food ...

is heterodont, also known as heteroglossan, in which the middle or rhachidian tooth in each array has multiple cusps and the lateral teeth are unicuspid. ''Vitreledonella richardi'' is

ovoviviparous Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a term used as a "bridging" form of reproduction between egg-laying oviparous and live-bearing viviparous reproduction. Ovoviviparous animals possess embryos that develop insi ...

. The female broods her eggs, of which hundreds are within the mantle cavity. Each egg measures about in length. Newborn larvae have a mantle length around . The young paralarvae are left to fend for themselves as the mother quickly dies after their birth. Researchers in Central Marine Fisheries Research Institute, conducted an experiment that later concluded young paralarvae beaks change as they get older, along with the depth of water which they want to live in. Younger paralarvae have stronger beaks to tear prey's flesh off since that was all they ate. Once they got older, they lose that beak and form a faint less developed one to eat softer bodied prey. With their diet changing, they are predicted to move up from deeper levels (between 310 and 440, but can be as far as 1000m) to the subsurface (between 110 and 300m) as they get older.

Ecology

Found mostly in the tropic and subtropic regions of seas worldwide, the glass octopus is

prey Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the ...

to the feeding ecology of Northern

bottlenose whale ''Hyperoodon'' (or ''Hyperoödon'') is a genus of beaked whale, containing just two species: the Northern and Southern bottlenose whales. While not in the genus ''Hyperoodon'', Longman's beaked whales are alternatively called tropical bottlen ...

s. More specifically noted is that of Tåsinge whale.Santos, M., Pierce, G., Smeenk, C., Addink, M., Kinze, C., Tougaard, S., & Herman, J. (2001). Stomach contents of northern bottlenose whales Hyperoodon ampullatus stranded in the North Sea. ''Journal of the Marine Biological Association of the United Kingdom,'' ''81''(1), 143-150.

References

* * Sajikumar, K. K., Venkatesan, V., Jeyabaskaran, R., Muhammed, A., & Mohamed, K. S. (2016). First record of the glass octopus Vitreledonella richardi (Cephalopoda: Vitreledonellidae) from the Arabian Sea. Marine Biodiversity Records, 9, 1–4.

External links

Tree of Life web project: ''Vitreledonella''

''Vitreledonella richardi'' - Marine species identification
Octopuses Molluscs described in 1918 {{octopus-stub