''Rossia'' is a genus of 10 species of

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...

bobtail squid Bobtail squid (order Sepiolida) are a group of cephalopods closely related to cuttlefish. Bobtail squid tend to have a rounder mantle than cuttlefish and have no cuttlebone. They have eight suckered arms and two tentacles and are generally qui ...

in the family Sepioidae found in all oceans. They live at depths greater than 50 m (164 ft) and can grow up to 9 cm (3.5 in.) in

mantle A mantle is a piece of clothing, a type of cloak. Several other meanings are derived from that. Mantle may refer to: *Mantle (clothing), a cloak-like garment worn mainly by women as fashionable outerwear **Mantle (vesture), an Eastern Orthodox ve ...

length. This genus was first discovered in 1832 by Sir John Ross and his nephew James Clark Ross in the Arctic Seas, showing a resemblance to another genus under the same family, ''

Sepiola ''Sepiola'' is a genus of bobtail squid comprising around 15 species: *'' Sepiola affinis'' Naef, 1912, anagolous bobtail *''Sepiola atlantica'' d'Orbigny in Ferussac & d'Orbigny, 1839-1841, Atlantic bobtail *'' Sepiola aurantiaca'' Jatta, 189 ...

.'' After returning from their expedition, Sir Richard Owen officially classified ''Rossia'' to be a new genus, naming it after Sir John and James Clark Ross.

Description

''Rossia'' are categorized under the subfamily

Rossiinae Rossiinae is a subfamily of bobtail squid encompassing four genus, genera and around twenty species. Classification *Subfamily Rossiinae **Genus ''Austrorossia'' ***''Austrorossia antillensis'', Antilles bobtail squid ***''Austrorossia australis ...

, which are identified by their short mantles and lack of ventral shield due to the unextended anterior ventral edge of the mantle. ''Rossia'' are distinguished by their dome-shaped mantles. which are not fused to their head. They are shorter in length compared to many other bobtail squid, with

length varying from 1.4 cm (0.5 in) to 9 cm (3.5 in). Males do not grow to be as large as females. Each squid under genus ''Rossia'' have broadly separated fins with free anterior and posterior lobes. Its tentacular club is expanded, with club suckers in series of 6 to 12 and no enlarged suckers are found on the lateral arms. They lack photophores, but do possess functioning

ink sac An ink sac is an anatomical feature that is found in many cephalopod mollusks used to produce the defensive cephalopod ink. With the exception of nocturnal and very deep water cephalopods, all Coleoidea (squid, octopus and cuttlefish) which dwell ...

s. They also have small internal,

chitin Chitin ( C8 H13 O5 N)n ( ) is a long-chain polymer of ''N''-acetylglucosamine, an amide derivative of glucose. Chitin is probably the second most abundant polysaccharide in nature (behind only cellulose); an estimated 1 billion tons of chit ...

ous pens.

Distribution and habitat

Rossia are distributed throughout marine, benthic habitats worldwide. Most are commonly found in sandy or muddy bottoms on the seafloor. There is currently an insufficient amount of information to know the conservation status of Rossia.

Behavior

''Rossia'' commonly bury themselves in sand by excavating a hole from underneath them by forcefully blowing water out of their siphon and throwing sand over their

with their arms. When predators are near, they release ink and jet themselves out of the sand, allowing for escape.

Feeding habits

For species that have been studied, ''Rossia's'' diet consists of

shrimp Shrimp are crustaceans (a form of shellfish) with elongated bodies and a primarily swimming mode of locomotion – most commonly Caridea and Dendrobranchiata of the decapod order, although some crustaceans outside of this order are refer ...

s and prawns, but they have sharp and hardened beak which allows them to consume small crabs, along with fish and other

cephalopod A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head ...

s. They often use two tentacles to grasp their prey.

Reproduction and development

Males perform a variety of acts to attract potential females partners for reproduction. ''Rossia'' commonly reproduce by internal fertilization. During mating, the male inserts the hectocotlyus into the mantle cavity of the female where fertilization takes place. Spawning takes place year round, where small egg masses are found on seaweed or smooth objects on the ocean floor. Male and female adults often die shortly after mating. Egg cases have a thick, dense outer layer to protect the

embryo An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...

s, and are an average of 10 mm in diameter; however, the egg does not expand with development, and the embryo grows inside the casing. When the egg masses of ''Rossia'' are ready to hatch, they push the tip of the mantle against the casing to break it, followed by the rest of its body.

References

{{Taxonbar, from=Q3201833 Bobtail squid Cephalopod genera