The smooth lumpfish (''Aptocyclus ventricosus'') 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), ...

of marine

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of sk ...

belonging to the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Cyclopteridae The Cyclopteridae are a family of marine fishes, commonly known as lumpsuckers or lumpfish, in the order Scorpaeniformes. They are found in the cold waters of the Arctic, North Atlantic, and North Pacific oceans. The greatest number of species ar ...

, the lumpfishes and lumpsuckers. This species is found in the northern Pacific Ocean. It is the only species in the monospecific genus ''Aptocyclus''.

Taxonomy

The smooth lumpfish was first formally described as ''Cyclopterus ventricosus'' in 1769 by the German

zoologist Zoology ( , ) is the scientific study of animals. Its studies include the structure, embryology, classification, habits, and distribution of all animals, both living and extinct, and how they interact with their ecosystems. Zoology is one ...

Peter Simon Pallas Peter Simon Pallas Fellow of the Royal Society, FRS FRSE (22 September 1741 – 8 September 1811) was a Prussia, Prussian zoologist, botanist, Ethnography, ethnographer, Exploration, explorer, Geography, geographer, Geology, geologist, Natura ...

with its type locality given as Tauyskaya Bay near Ol'skiy Island in the

Sea of Okhotsk The Sea of Okhotsk; Historically also known as , or as ; ) is a marginal sea of the western Pacific Ocean. It is located between Russia's Kamchatka Peninsula on the east, the Kuril Islands on the southeast, Japan's island of Hokkaido on the sou ...

. In 1835 Auguste-Jean-Marie Bachelot De la Pylaie placed ''C. ventricosus'' in the

monospecific genus 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 "unispe ...

''Aptocyclus''. The 5th edition of ''

Fishes of the World ''Fishes of the World'' is a standard reference for the systematics of fishes. It was first written in 1976 by the American ichthyologist Joseph S. Nelson (1937–2011). Now in its fifth edition (2016), the work is a comprehensive overview of t ...

'' does not recognize subfamilies within the Cyclopteridae, however, other authorities place the smooth lumpfish in the subfamily Liparopsinae.

Description

The smooth lumpfish, or smooth lumpsucker, is a deep sea fish species with a body length of and body weight of on average. They look brownish gray with dark spots dorsally, muddy gray ventrally. They have naked skin without scales and tubercles. A smooth lumpfish has no dorsal spines or anal spines, eight to nine dorsal soft rays, and seven to nine anal soft rays. They have a rounded caudal fin and large and broadly based pectoral fins. Their pelvic fins are modified to form a clinging disc with a thickened margin on the ventral surface of the body. They have their first dorsal fins completed embedded under the skin.

Habitat and diet

Smooth lumpfish are widely distributed throughout the

North Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the contine ...

, especially in the

Aleutian Basin The Aleutian Basin is an oceanic basin located beneath the southwestern Bering Sea. While the northeastern half of the Bering Sea is situated over the North American Plate in relatively shallow waters, the Aleutian Basin comprises an oceanic pl ...

. They inhabit both near-bottom and mid-water layers, ranging from 5to 1,700m. They are preyed upon by certain fish species,

marine mammals Marine mammals are mammals that rely on marine ecosystems for their existence. They include animals such as cetaceans, pinnipeds, sirenians, sea otters and polar bears. They are an informal group, unified only by their reliance on marine env ...

and

seabirds Seabirds (also known as marine birds) are birds that are adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same envi ...

. Their preferred diet consists of

medusa In Greek mythology, Medusa (; ), also called Gorgo () or the Gorgon, was one of the three Gorgons. Medusa is generally described as a woman with living snakes in place of hair; her appearance was so hideous that anyone who looked upon her wa ...

and

ctenophores Ctenophora (; : ctenophore ) is a phylum of marine invertebrates, commonly known as comb jellies, that marine habitats, inhabit sea waters worldwide. They are notable for the groups of cilia they use for swimming (commonly referred to as "combs ...

, and they occasionally also feed on pelagic

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 ...

and

crustaceans Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of Arthropod, arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquat ...

Reproduction

The smooth lumpfish is an

iteroparous Semelparity and iteroparity are two contrasting reproductive strategies available to living organisms. A species is considered ''semelparous'' if it is characterized by a single reproduction, reproductive episode before death, and ''iteroparous ...

gonochoristic In biology, gonochorism is a sexual system where there are two sexes and each individual organism is either male or female. The term gonochorism is usually applied in animal species, the vast majority of which are gonochoric. Gonochorism contras ...

species with determinate

fecundity Fecundity is defined in two ways; in human demography, it is the potential for reproduction of a recorded population as opposed to a sole organism, while in population biology, it is considered similar to fertility, the capability to produc ...

, group-synchronous ovary organization, total

spawning Spawn is the Egg cell, eggs and Spermatozoa, sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of freely releasing eggs and sperm into a body of water (fresh or marine); the physical act is ...

(release of 1 batch of eggs per breeding season), and

external fertilization External fertilization is a mode of reproduction in which a male organism's sperm fertilizes a female organism's egg outside of the female's body. It is contrasted with internal fertilization, in which sperm are introduced via insemination and then ...

. Smooth lumpfish perform spawning migration from deep-ocean to coastal zones, where breeding occurs over a rocky bottom at depths shallower than . A thick envelope protects these

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 o ...

eggs from mechanical damage during development in the coastal zone. The

incubation time Incubation period (also known as the latent period or latency period) is the time elapsed between exposure to a pathogenic organism, a chemical, or radiation, and when symptoms and signs are first apparent. In a typical infectious disease, the in ...

between fertilization and hatching is more than 40days. Males protect the egg clusters after females spawn.

References

{{Taxonbar, from=Q2672261, from2=Q2119379 Cyclopteridae Fish described in 1769 Taxa named by Peter Simon Pallas Fish of the North Pacific Fish of the Bering Sea