''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 the Ancient Greek word (), meaning "the depths". ...

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

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 explorer of both the northern and southern polar regions. In the Arctic, he participated in two expeditions led by his uncle, Sir John Ross, John ...

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'' Adolf Naef, Naef, 1912, anagolous bobtail *''Sepiola atlantica'' Alcide d'Orbigny, d'Orbigny in André Étienne d'Audebert de Férussac, Ferussac & d'Orbi ...

.'' After returning from their expedition,

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

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 describe unambiguously the anatomy of humans and other animals. 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 cephalopod beak, beaks. These appendages, which function as muscular hydrostats, have been variously termed arms, legs or tentacles. Description In ...

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 specialized anatomical structure found in a variety of organisms that emits light through the process of Bioluminescence, boluminescence. This light may be produced endogenously by the organism itself (symbiotic) or generat ...

, 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 (carbon, C8hydrogen, H13oxygen, O5nitrogen, N)n ( ) is a long-chain polymer of N-Acetylglucosamine, ''N''-acetylglucosamine, an amide derivative of glucose. Chitin is the second most abundant polysaccharide in nature (behind only cell ...

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 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

shrimp A shrimp (: shrimp (American English, US) or shrimps (British English, UK)) is a crustacean with an elongated body and a primarily Aquatic locomotion, swimming mode of locomotion – typically Decapods belonging to the Caridea or Dendrobranchi ...

s and

prawn Prawn is a common name for small aquatic crustaceans with an exoskeleton An exoskeleton () . is a skeleton that is on the exterior of an animal in the form of hardened integument, which both supports the body's shape and protects the intern ...

s, 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 Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...

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 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

embryo An embryo ( ) is the initial stage of development for 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 sp ...

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