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

octopus An octopus (: octopuses or octopodes) 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, cuttlefish, and nautiloids. Like oth ...

. It is in the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

'' Vitreledonella'' and of the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Amphitretidae Amphitretidae is a Family (biology), family of mesopelagic octopods which contains three subfamily, subfamilies, formerly classified as families in their own right. It is classified in the Superfamily (taxonomy), superfamily Octopodoidea. Species ...

Description

''Vitreledonella richardi'' is a transparent, gelatinous, and nearly colorless. Adults reach up to 11 cm (4.3 in) in mantle length and a total length of up to 45 cm (18 in). The upper three pairs of arms are subequal in length, about as long as the mantle in juveniles and two to three times longer in adults. The fourth, ventral pair is slightly shorter. Suckers are small, widely spaced, and arranged in a single row. Males possess a hectocotlylized third left arm, capable of detaching to deliver sperm during mating. Among mature males, the large

ampulla An ampulla (; : ampullae) 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 ho ...

and elongate accessory gland are prominent within the reproductive system. The species has distinctive rectangular eyes when viewed laterally. This cylindrical design, with a centered lens, limits horizontal vision but is believed to minimize the eye’s silhouette when viewed from below, aiding in

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 ...

. Its

radula The radula (; : radulae or radulas) is an anatomical structure used by mollusks 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 enters ...

heterodont In anatomy, a heterodont (from Greek, meaning 'different teeth') is an animal which possesses more than a single tooth morphology. Human dentition is heterodont and diphyodont as an example. In vertebrates, heterodont pertains to animals wher ...

(or heteroglossan), featuring a multicuspid central rhachidian tooth and

unicuspid A unicuspid is a tooth that has only one cusp. In shrews The dental formulas of shrews are distinguished by the number of unicuspids. All shrews have (in one half of each jaw) one large incisor followed by a variable number of unicuspids, followe ...

lateral teeth.

Distribution and habitat

''Vitreledonella richardi'' is found in tropical and subtropical seas worldwide. It inhabits

mesopelagic The mesopelagic zone (Greek language, 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 ...

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 bathypela ...

zones of the ocean, typically at depths where sunlight penetration is minimal. Due to its deep-sea habitat, encounters with this species in the wild are rare. One of the few documented observations occurred in 2021, when researchers from

Boston University Boston University (BU) is a Private university, private research university in Boston, Massachusetts, United States. BU was founded in 1839 by a group of Boston Methodism, Methodists with its original campus in Newbury (town), Vermont, Newbur ...

recorded video footage of two individuals during an expedition aboard the research vessel ''Falkor''.

Reproduction

''Vitreledonella richardi'' is

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

. 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

paralarva Coleoidea or Dibranchiata is one of the two subclasses of cephalopod molluscs containing all the various taxa popularly thought of as "soft-bodied" or "shell-less" (i.e. octopus, squid and cuttlefish). Unlike its extant sister group Nautiloidea ...

e are left to fend for themselves as the mother quickly dies after their birth. Researchers at 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 1000 m) to the subsurface (between 110 and 300 m) as they get older.

Ecology

The glass octopus is prey to 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 bottle ...

s, including a specific individual known as the 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
{{Taxonbar, from=Q3816073 Octopuses Cephalopods described in 1918