The Korean skate (''Hongeo koreana'') is a

skate Skate or Skates may refer to: Fish *Skate (fish), several genera of fish belonging to the family Rajidae * Pygmy skates, several genera of fish belonging to the family Gurgesiellidae * Smooth skates or leg skates, several genera of fish belongin ...

in the family Rajidae, and is the sole member of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

''Hongeo''. It was previously classified in the genus ''

Raja ''Raja'' (; from , IAST ') is a royal title used for South Asian monarchs. The title is equivalent to king or princely ruler in South Asia and Southeast Asia. The title has a long history in South Asia and Southeast Asia, being attested f ...

'' as ''Raja koreana'' until discoveries identified this species as a member of a distinct genus. It is considered Critically Endangered on the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biol ...

due to overexploitation.

Taxonomy and systematics

Mitochondrial genome

The complete

mitochondrial genome Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial D ...

was investigated in 2014. The genome is 16,906

base pair A base pair (bp) is a fundamental unit of double-stranded nucleic acids consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix and contribute to the folded structure of both DNA ...

s in length, and contains 2

rRNA Ribosomal ribonucleic acid (rRNA) is a type of non-coding RNA which is the primary component of ribosomes, essential to all cells. rRNA is a ribozyme which carries out protein synthesis in ribosomes. Ribosomal RNA is transcribed from ribosoma ...

, 22

tRNA Transfer RNA (abbreviated tRNA and formerly referred to as sRNA, for soluble RNA) is an adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length (in eukaryotes), that serves as the physical link between the mRNA and the amino ac ...

, and 13 protein coding genes. The genome has the same gene order and structure as genomes of the other Rajidae species, which is the family that ''Hongeo koreana'' belongs to.

Etymology

*''Hongeo'' comes from the

Korean Korean may refer to: People and culture * Koreans, ethnic group originating in the Korean Peninsula * Korean cuisine * Korean culture * Korean language **Korean alphabet, known as Hangul or Chosŏn'gŭl **Korean dialects and the Jeju language ** ...

word for 'skate', (). *''koreana'' comes from its geographic range in the

Korea Korea ( ko, 한국, or , ) is a peninsular region in East Asia. Since 1945, it has been divided at or near the 38th parallel, with North Korea (Democratic People's Republic of Korea) comprising its northern half and South Korea (Republic o ...

n waters where it was collected.

Description

The Korean skate has a relatively short, deep

snout A snout is the protruding portion of an animal's face, consisting of its nose, mouth, and jaw. In many animals, the structure is called a muzzle, rostrum, or proboscis. The wet furless surface around the nostrils of the nose of many mammals is c ...

that is slightly obtuse. Its mouth is weakly arched and large, with 51 rows of teeth. It has five pairs of

gill slit Gill slits are individual openings to gills, i.e., multiple gill arches, which lack a single outer cover. Such gills are characteristic of cartilaginous fish such as sharks and rays, as well as deep-branching vertebrates such as lampreys. In con ...

s. For fins, the Korean skate has two

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...

s located near each other close to the tip of the tail, with a small, low

caudal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

located near to the second dorsal fin. Its tail is shorter than its body length, with a groove along the

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 language, Greek roots, describe something in its standard anatomical position. Th ...

midline and a well-developed

lateral Lateral is a geometric term of location which may refer to: Healthcare *Lateral (anatomy), an anatomical direction *Lateral cricoarytenoid muscle *Lateral release (surgery), a surgical procedure on the side of a kneecap Phonetics *Lateral cons ...

fold on the tail, extending to the tip of the tail. Its coloration is slightly different for males than females as the males are overall blacker than females, but other than that they look very similar in terms of color. The females’

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal co ...

surface is brown with scattered dark brown spots and indistinct marks. The

surface is black/brown with gray surrounding the pores (the

nostril A nostril (or naris , plural ''nares'' ) is either of the two orifices of the nose. They enable the entry and exit of air and other gasses through the nasal cavities. In birds and mammals, they contain branched bones or cartilages called turbi ...

s and

s). Similarly, the tail's dorsal surface is brown with 3 brown bands and dark brown spots, while the tail's ventral surface is gray. The Korean skate has several distinct characteristics. One is

cartilage Cartilage is a resilient and smooth type of connective tissue. In tetrapods, it covers and protects the ends of long bones at the joints as articular cartilage, and is a structural component of many body parts including the rib cage, the neck an ...

that is continuous with the

neurocranium In human anatomy, the neurocranium, also known as the braincase, brainpan, or brain-pan is the upper and back part of the skull, which forms a protective case around the brain. In the human skull, the neurocranium includes the calvaria (skull), ...

. The cartilage is proximally stout, very slender, and distally uncalcified. Another is a distinct row of thorns along the midline of the dorsal surface of the tail. Both males and females display this row of thorns. Most thorns are directed

anterior 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 ...

ly.

Distribution and habitat

The Korean skate is found mostly in the southern coast of the

Korean Peninsula Korea ( ko, 한국, or , ) is a peninsular region in East Asia. Since 1945, it has been divided at or near the 38th parallel, with North Korea (Democratic People's Republic of Korea) comprising its northern half and South Korea (Republic o ...

, in a relatively small area including the

Jeju Strait Jeju Strait is a strait between the Korean Peninsula (South Jeolla Province) and Jeju Island (Jeju Province). The strait is the boundary between the Sea of Japan and the Yellow Sea as defined by the International Hydrographic Organization, and i ...

, Heuksan Islands, and

Cheongsando Cheongsando (hangul: 청산도) is an island off the south coast of the Republic of Korea, being the main island of Cheongsan-myeon, Wando County, South Jeolla Province. Accompanied by the four inhabited islands of Daemodo, Somodo, Yeoseodo ...

. The species has also been found off the shore of

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

, near

Tsushima Island is an island of the Japanese archipelago situated in-between the Tsushima Strait and Korea Strait, approximately halfway between Kyushu and the Korean Peninsula. The main island of Tsushima, once a single island, was divided into two in 1671 b ...

and the

Gotō Islands The are Japanese islands in the East China Sea, off the western coast of Kyūshū. They are part of Nagasaki Prefecture. Geography There are 140 islands, including five main ones: , , , , and . The group of islands runs approximately fr ...

, but these reports are rarer. Their depth range is , off the southern coast of the Korean Peninsula, and when they have been found off the coast of Japan.

Life cycle

The Korean skate is

oviparous Oviparous animals are animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive method of most fish, amphibians, most reptiles, and all pterosaurs, dinosaurs (including birds), and ...

, meaning that they lay eggs. The females lay the eggs on muddy or sandy substrates. The embryos feed solely on yolk when in the egg. The eggs have horn-like projections on the shell.

Consumption

''Hongeo koreana'' is a relatively high

commercial fishery Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often ...

target species in southern Korea. A Korean fish specialty dish is

Hongeo-hoe ''Hongeo-hoe'' * () is a type of fermented fish dish from Korea's Jeolla province. ''Hongeo-hoe'' is made from skate and emits a very strong, characteristic ammonia-like odor that has been described as being "reminiscent of an outhouse". Orig ...

(), which is a

fermented Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzymes. In biochemistry, it is narrowly defined as the extraction of energy from carbohydrates in the absence of oxygen. In food ...

skate dish that is famous for its sharp, pungent aroma and a texture that is hard to swallow due to the fish's cartilage. The dish is usually prepared and eaten raw. Not all Hongeo-hoe is made from ''Hongeo koreana'', but any skate can be used, including the Korean skate.

References

* {{taxonbar, from=Q5030143, from2=Q17299722 Korean skate Endemic fauna of Korea Fish of Korea Korean skate