The Korean skate (''Hongeo koreana'') is a
skate in the family
Rajidae, and is the sole member of the
genus ''Hongeo''. It was previously classified in the genus ''
Raja'' 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 due to overexploitation.
Taxonomy and systematics
Mitochondrial genome
The complete
mitochondrial genome 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, 22
tRNA, 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 word for 'skate', ().
*''koreana'' comes from its geographic range in the
Korean 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 slits. For fins, the Korean skate has two
dorsal fins located near each other close to the tip of the tail, with a small, low
caudal fin located near to the second dorsal fin. Its tail is shorter than its body length, with a groove along the
ventral midline and a well-developed
lateral 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 surface is brown with scattered dark brown spots and indistinct marks. The
ventral surface is black/brown with gray surrounding the pores (the
nostrils and
gill slits). 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. The cartilage is proximally stout, very slender, and distally