Mawson's dragonfish (''Cygnodraco mawsoni'') is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

Antarctic dragonfish The Bathydraconidae, or the Antarctic dragonfishes, are a family (taxonomy), family of marine ray-finned fishes, notothenioids belonging to the Perciform suborder Notothenioidei. The family comprises four genera. These fishes are endemic to deep ...

native to the

Southern Ocean The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the world ocean, generally taken to be south of 60th parallel south, 60° S latitude and encircling Antarctica. With a size of , it is the seco ...

around

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. ...

. It is found at depths of from over the

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an islan ...

. This species is the only known member of its

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 ...

Taxonomy

Mawson's dragonfish was first formally described in 1916 by the British-born Australian

ichthyologist Ichthyology is the branch of zoology devoted to the study of fish, including bony fish (Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). According to FishBase, 35,800 species of fish had been described as of March 2 ...

Edgar Ravenswood Waite Edgar Ravenswood Waite (5 May 1866 – 19 January 1928) was a British/Australian zoologist, ichthyologist, herpetologist, and ornithologist. Waite was born in Leeds, Yorkshire, England England is a Countries of the United Kingdom, count ...

with the type locality given as

Queen Mary Land Queen Mary Land or the Queen Mary Coast () is the portion of the coast of Antarctica lying between Cape Filchner, in 91° 54' E, and Cape Hordern, at 100° 30' E. It is claimed by Australia as part of the Australian Antarctic Territory. It ...

off Drygalski Island where it was collected by the

Australian Antarctic Expedition The Australasian Antarctic Expedition was a 1911–1914 expedition headed by Douglas Mawson that explored the largely uncharted Antarctic coast due south of Australia. Mawson had been inspired to lead his own venture by his experiences on Ernest ...

. Waite described it as the only species in a

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

genus. The genus name is a combination of ''cygnus'' meaning "swan", an allusion Waite did not explain but may be a reference to the somewhat duck-bill shaped snout, and ''draco'' which means "dragon", a common suffix used In Notothenioid fishes. The specific name honours the Australian

geologist A geologist is a scientist who studies the structure, composition, and History of Earth, history of Earth. Geologists incorporate techniques from physics, chemistry, biology, mathematics, and geography to perform research in the Field research, ...

Douglas Mawson Sir Douglas Mawson (5 May 1882 – 14 October 1958) was a British-born Australian geologist, Antarctic explorer, and academic. Along with Roald Amundsen, Robert Falcon Scott, and Sir Ernest Shackleton, he was a key expedition leader during ...

who led the Australasian Antarctic Expedition.

Description

Mawson's dragonfish has a slender, naked body with the only scales being in the two

lateral line The lateral line, also called the lateral line organ (LLO), is a system of sensory organs found in fish, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelia ...

s, the upper lateral line is wholly made up of perforated scales. There is a flattened ridge on the operculum which divides towards the margin. They have a thin band of conical teeth in the jaws. The

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

has 61-66 soft rays while the

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

has 36-38. In alcohol the overall colour is brown with darker saddles and bars, the median fins are darker than the

pectoral Pectoral may refer to: * The chest region and anything relating to it. * Pectoral cross, a cross worn on the chest * a decorative, usually jeweled version of a gorget * Pectoral (Ancient Egypt), a type of jewelry worn in ancient Egypt * Pectora ...

and

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral (belly) surface of fish, and are the lower of the only two sets of paired fins (the other being the laterally positioned pectoral fins). The pelvic fins are homologous to the hi ...

s. This species grows to a length of

standard length Fish measurement is the measuring of individual fish and various parts of fish anatomy, their anatomies, for data used in many areas of ichthyology, including Taxonomy (biology), taxonomy and fishery biology. Overall length Standard length (SL) is ...

Distribution and habitat

Mawson's dragonfish is found in the Southern Ocean over the Antarctic continental shelf. It is a demersal species found at depths of .

Biology

Mawson's dragonfish in the

Weddell Sea The Weddell Sea is part of the Southern Ocean and contains the Weddell Gyre. Its land boundaries are defined by the bay formed from the coasts of Coats Land and the Antarctic Peninsula. The easternmost point is Cape Norvegia at Princess Martha C ...

are adult at and start breeding at . Spawning takes place during the autumn and early winter. They feed largely on

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". ...

and

benthopelagic The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a layer of ...

organisms such as fishes, especially rockcods in the genus '' Trematomus'' and the

decapod The Decapoda or decapods, from Ancient Greek δεκάς (''dekás''), meaning "ten", and πούς (''poús''), meaning "foot", is a large order of crustaceans within the class Malacostraca, and includes crabs, lobsters, crayfish, shrimp, and p ...

'' Notocrangon antarcticus'' as well as ''mysids'', gammarids and

polychaetes Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are m ...

References

{{Taxonbar, from=Q2037719 Bathydraconidae Fish of Antarctica Fish described in 1916 Taxa named by Edgar Ravenswood Waite