''Helicolenus hilgendorfii'', Hilgendorf's saucord, is a species of marine

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or hor ...

belonging to the

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...

Sebastinae Sebastinae is a subfamily of marine fish belonging to the family Scorpaenidae in the order Scorpaeniformes. Their common names include rockfishes, rock perches, ocean perches, sea perches, thornyheads, scorpionfishes, sea ruffes and rockcods. D ...

, part of the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Scorpaenidae The Scorpaenidae (also known as scorpionfish) are a family of mostly marine fish that includes many of the world's most venomous species. As their name suggests, scorpionfish have a type of "sting" in the form of sharp spines coated with venom ...

. It is found in the northwestern Pacific Ocean.

Taxonomy

''Helicolenus hilgendorfii'' was first formally described in 1884 as ''Sebastes hilgendorfii'' by the German

zoologist Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the Animal, animal kingdom, including the anatomy, structure, embryology, evolution, Biological clas ...

Ludwig Heinrich Philipp Döderlein Ludwig Heinrich Philipp Döderlein (3 March 1855, Bad Bergzabern – 23 April 1936, Munich) was a German zoologist. He specialized in echinoderms, particularly sea stars, sea urchins, and crinoids. He was one of the first European zoologists to ...

with the type locality given as

Tokyo Tokyo (; ja, 東京, , ), officially the Tokyo Metropolis ( ja, 東京都, label=none, ), is the capital and largest city of Japan. Formerly known as Edo, its metropolitan area () is the most populous in the world, with an estimated 37.468 ...

, although no

types Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * Typ ...

are known. Döderlein did not state who was honoured in the

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

but it is certainly the German zoologist and

palaeontologist Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...

Franz Martin Hilgendorf Franz Martin Hilgendorf (5 December 1839 – 5 July 1904) was a German zoologist and paleontologist. Hilgendorf's research on fossil snails from the Steinheim crater in the early 1860s became a palaeontological evidence for the theory of e ...

whose work on Japanese fishes was often referred to by Döderlein.

Description

''Helicolenus hilgendorfii'' attains a maximum

standard length Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish m ...

of . It has an elongated, compressed body with a large head which has weak spines. The orbit protrudes a little over the dorsal profile of the head. They do not have a swim bladder. There are no teeth in the front of the jaws. The preoperculum has 5 spines and the operculum has 2. The body is covered with

ctenoid A fish scale is a small rigid plate that grows out of the skin of a fish. The skin of most jawed fishes is covered with these protective scales, which can also provide effective camouflage through the use of reflection and colouration, as ...

scales and there are 26-27 scales in the

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 epithelial ...

. The

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 ...

has 12 short spines with the membranes between them being slightly notched, and 11-13 soft rays. The

anal 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 ...

is slightly shorter than the spiny dorsal fin and contains 3 spines and 4-6 soft rays. The

pectoral 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 ...

extends to just in front of the anus while the

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral surface of fish. The paired pelvic fins are homologous to the hindlimbs of tetrapods. Structure and function Structure In actinopterygians, the pelvic fin consists of two en ...

has a single spine and 5 soft rays and the

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 ...

truncate In mathematics and computer science, truncation is limiting the number of digits right of the decimal point. Truncation and floor function Truncation of positive real numbers can be done using the floor function. Given a number x \in \mathbb ...

. The body is light red in colour with orange-red mottling on the flanks above the lateral line. The spines of the dorsal fin are orange-red with the rest of the fin being a light colour.

Distribution and habitat

''Helicolenus hilgendorfii'' is found in the northwestern Pacific Ocean from Japan and southern Korea southwards into the

East China Sea The East China Sea is an arm of the Western Pacific Ocean, located directly offshore from East China. It covers an area of roughly . The sea’s northern extension between mainland China and the Korean Peninsula is the Yellow Sea, separated b ...

. It is a

demersal 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 ...

species which is found in areas of sandy and muddy substrates. it is found at depths of .

Biology

''Helicolenus hilgendorfii'' is

viviparous Among animals, viviparity is development of the embryo inside the body of the parent. This is opposed to oviparity which is a reproductive mode in which females lay developing eggs that complete their development and hatch externally from the m ...

. This is a carnivorous fish which although specialised to feed on shrimps, especially ''

Crangon hakodatei ''Crangon'' is a genus of shrimp. Distribution ''Crangon'' species are found exclusively in the Northern Hemisphere, with most of the species occurring in the northern Pacific Ocean. '' C. septemspinosa'' is the only species in the genus t ...

'', it is an opportunistic predator and as the fish grows it consumes less shrimps and more fishes. The

krill Krill are small crustaceans of the order Euphausiacea, and are found in all the world's oceans. The name "krill" comes from the Norwegian Norwegian, Norwayan, or Norsk may refer to: *Something of, from, or related to Norway, a country in n ...

species ''

Euphausia pacifica ''Euphausia pacifica'', the North Pacific krill, is a euphausid that lives in the northern Pacific Ocean. In Japan, ''E. pacifica'' is called ''isada krill'' or ' (ツノナシオキアミ). It is found from Suruga Bay northwards, including all ...

'' has also been recorded as a prey item for this fish.

Taxonomy

Description

Distribution and habitat

Biology

References

Further reading