The spineless sculpin (''Phallocottus obtusus'') 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 ...

Cottidae The Cottidae are a family of fish in the superfamily Cottoidea, the sculpins. It is the largest sculpin family, with about 275 species in 70 genera.Kane, E. A. and T. E. Higham. (2012)Life in the flow lane: differences in pectoral fin morphology ...

, the typical

sculpin A sculpin is a type of fish that belongs to the superfamily Cottoidea in the order Perciformes.Kane, E. A. and T. E. Higham. (2012)Life in the flow lane: differences in pectoral fin morphology suggest transitions in station-holding demand acros ...

s. This species is found in the Pacific Ocean where it is

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to the waters around the

Aleutian Islands The Aleutian Islands ( ; ; , "land of the Aleuts"; possibly from the Chukchi language, Chukchi ''aliat'', or "island")—also called the Aleut Islands, Aleutic Islands, or, before Alaska Purchase, 1867, the Catherine Archipelago—are a chain ...

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

Taxonomy

The spineless sculpin was first formally described in 1938 by the American

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 ...

Leonard Peter Schultz Leonard Peter Schultz (1901–1986) was an American ichthyologist. Biography Schultz was born in 1901, at Albion, Michigan. He received education on ichthyology at Albion College, in which he got his bachelor's degree, in 1924. In 1926, he got ...

with its type locality given as Igitkin Island. Schultz classified the spineless sculpin in the new

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 ...

''Phallocottus''. 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 ...

'' classifies this genus within the subfamily

Cottinae Cottinae is a subfamily of ray-finned fishes belonging to the Family (biology), family Cottidae, the typical sculpins. The subfamily has species throughout the northern hemisphere in both marine and freshwater habitats. Genera The following gener ...

of the family Cottidae, however, other authors classify the genus within the subfamily

Psychrolutinae The fish family Psychrolutidae (commonly known as blobfishes, flathead sculpins, or tadpole sculpins) contains over 35 recognized species in 8 genera. This family consists of bottom-dwelling marine sculpins shaped like tadpoles, with large heads ...

of the family

Psychrolutidae The fish family Psychrolutidae (commonly known as blobfishes, flathead sculpins, or tadpole sculpins) contains over 35 recognized species in 8 genera. This family consists of bottom-dwelling marine sculpins shaped like tadpoles, with large heads ...

Etymology

The spineless sculpin's genus name prefixes the name of the type genus of the Cottidae, '' Cottus'' with ''phallos'', which means "

penis A penis (; : penises or penes) is a sex organ through which male and hermaphrodite animals expel semen during copulation (zoology), copulation, and through which male placental mammals and marsupials also Urination, urinate. The term ''pen ...

". This is an allusion to the conical

papilla Papilla (Latin, 'nipple') or papillae may refer to: In animals * Papilla (fish anatomy), in the mouth of fish * Papilla (worms), small bumps on the surface of certain worms * Basilar papilla, a sensory organ of lizards, amphibians and fish * ...

e at the

anus In mammals, invertebrates and most fish, the anus (: anuses or ani; from Latin, 'ring' or 'circle') is the external body orifice at the ''exit'' end of the digestive tract (bowel), i.e. the opposite end from the mouth. Its function is to facil ...

. 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 ...

''obtusus'' means "blunt" and is a reference to rather blunt and rounded spine on the

preoperculum This glossary of ichthyology is a list of definitions of terms and concepts used in ichthyology, the study of fishes. A B C ...

Description

The spineless sculpin was classified in its own monotypic genus because it differs from related genera by having a combination of no teeth on the

palatine A palatine or palatinus (Latin; : ''palatini''; cf. derivative spellings below) is a high-level official attached to imperial or royal courts in Europe since Roman Empire, Roman times.

and having an arched

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 ...

with smooth skin, a short, rounded blunt preopercular spine and the gill membranes are broadly joined across the throat. The position of the anus, closer to the

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 than 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 ...

, is also a distinguishing character.

Distribution and habitat

The spineless sculpin is found in the North Pacific Ocean where it is only known from the waters around the Aleutian Islands. It is a

demersal fish Demersal fish, also known as groundfish, live and feed on or near the bottom of seas or lakes (the demersal zone).Walrond Carl . "Coastal fish - Fish of the open sea floor"Te Ara - the Encyclopedia of New Zealand. Updated 2 March 2009 They oc ...

that occurs at depths of from .

References

{{Taxonbar, from=Q2118411 Cottinae Endemic fauna of Alaska Endemic fish of the United States