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

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 length. This genus was first discovered in 1832 by

Sir John Ross Sir John Ross (24 June 1777 – 30 August 1856) was a Scottish Royal Navy officer and polar explorer. He was the uncle of Sir James Clark Ross, who explored the Arctic with him, and later led expeditions to Antarctica. Biography Ear ...

and his nephew

James Clark Ross Sir James Clark Ross (15 April 1800 – 3 April 1862) was a British Royal Navy officer and polar explorer known for his explorations of the Arctic, participating in two expeditions led by his uncle John Ross, and four led by William Edwa ...

in the Arctic Seas, showing a resemblance to another genus under the same family, '' Sepiola.'' After returning from their expedition,

Sir Richard Owen Sir Richard Owen (20 July 1804 – 18 December 1892) was an English biologist, comparative anatomist and paleontologist. Owen is generally considered to have been an outstanding naturalist with a remarkable gift for interpreting fossils. Ow ...

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, which are identified by their short mantles and lack of

ventral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

shield due to the unextended anterior

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 mantle 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 All cephalopods possess flexible limbs extending from their heads and surrounding their beaks. These appendages, which function as muscular hydrostats, have been variously termed arms, legs or tentacles. Description In the scientific l ...

is expanded, with club suckers in series of 6 to 12 and no enlarged suckers are found on the lateral arms. They lack

photophores A photophore is a glandular organ that appears as luminous spots on various marine animals, including fish and cephalopods. The organ can be simple, or as complex as the human eye; equipped with lenses, shutters, color filters and reflectors, ...

, 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, chitinous 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 mantle 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 shrimps and

prawn Prawn is a common name for small aquatic crustaceans with an exoskeleton and ten legs (which is a member of the order decapoda), some of which can be eaten. The term "prawn"Mortenson, Philip B (2010''This is not a weasel: a close look at nature' ...

s, but they have sharp and hardened beak which allows them to consume small crabs, along with fish and other cephalopods. 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 The mantle (also known by the Latin word pallium meaning mantle, robe or cloak, adjective pallial) is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of ...

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 embryos, 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