The phallic catshark (''Galeus priapus'') is a little-known

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

catshark Catsharks are ground sharks of the family Scyliorhinidae. They are the largest family of sharks with around 160 species placed in 17 genera. Although they are generally known as catsharks, some species can also be called dogfish due to previous ...

, belonging to the

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

Scyliorhinidae. It is found on or near the ocean floor, in the deep waters off New Caledonia and

Vanuatu Vanuatu ( or ; ), officially the Republic of Vanuatu (french: link=no, République de Vanuatu; bi, Ripablik blong Vanuatu), is an island country located in the South Pacific Ocean. The archipelago, which is of volcanic origin, is east of no ...

. A slender species attaining a length of , it is characterized by a long

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 s ...

bearing a crest of enlarged

dermal denticle 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 w ...

s along the dorsal margin, and very long

claspers In biology, a clasper is a male anatomical structure found in some groups of animals, used in mating. Male cartilaginous fish have claspers formed from the posterior portion of their pelvic fin which serve to channel semen into the female's c ...

in adult males. This shark is gray-colored, with four dark saddles along the back and tail.

Taxonomy

The first specimens of ''G. priapus'' were collected in the 1990s, during a series of

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

research cruises jointly undertaken by the

Institut de recherche pour le développement The Institut de Recherche pour le Développement or IRD () is a French science and technology establishment under the joint supervision of the French Ministries of Higher Education and Research and Foreign Affairs. It operates internationally ...

(IRD) and the

Muséum national d'histoire naturelle The French National Museum of Natural History, known in French as the ' (abbreviation MNHN), is the national natural history museum of France and a ' of higher education part of Sorbonne Universities. The main museum, with four galleries, is loca ...

(MNHN). Bernard Séret and Peter Last described the new species in a 2008 volume of the

scientific journal In academic publishing, a scientific journal is a periodical publication intended to further the progress of science, usually by reporting new research. Content Articles in scientific journals are mostly written by active scientists such ...

''Zootaxa''. It was given the

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''priapus'' after the Greek fertility god

Priapos In Greek mythology, Priapus (; grc, Πρίαπος, ) is a minor rustic fertility god, protector of livestock, fruit plants, gardens and male genitalia. Priapus is marked by his oversized, permanent erection, which gave rise to the medical term ...

, in reference to the distinctively long

of males. The

type specimen In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes the ...

is a long adult male

trawl Trawling is a method of fishing that involves pulling a fishing net through the water behind one or more boats. The net used for trawling is called a trawl. This principle requires netting bags which are towed through water to catch different spe ...

ed by the RV ''Alis'' off New Caledonia on March 30, 1994. Within the genus, this species most closely resembles the

slender sawtail catshark The slender sawtail catshark (''Galeus gracilis'') is a little-known species of catshark, part of the family Scyliorhinidae, endemic to northern Australia. It is found over the continental slope in on water. Growing to long, this shark ha ...

(''G. gracilis'').

Distribution and habitat

''Galeus priapus'' is a demersal species that has been recorded from a depth of on the slopes of

seamount A seamount is a large geologic landform that rises from the ocean floor that does not reach to the water's surface (sea level), and thus is not an island, islet or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise a ...

s and submarine ridges off New Caledonia, between the

Loyalty Islands The Loyalty Islands Province (French ''Province des îles Loyauté'') is one of three administrative subdivisions of New Caledonia encompassing the Loyalty Island (french: Îles Loyauté) archipelago in the Pacific, which are located northeast o ...

and the

Norfolk Ridge The Norfolk Ridge is a long submarine ridge running between New Caledonia and New Zealand, about 1300 km off the east-coast of Australia. It is part of a complex region of ridges between the crust of the Pacific Basin and the continental ...

, as well as from a depth of off

Espiritu Santo Island Espiritu Santo (, ; ) is the largest island in the nation of Vanuatu, with an area of and a population of around 40,000 according to the 2009 census. Geography The island belongs to the archipelago of the New Hebrides in the Pacific region o ...

Description

''Galeus priapus'' is a firm-bodied, very slim shark that reaches at least in length. The head has a long, narrow parabolic shape from above. The small, horizontal eyes are placed rather high on the head, and equipped with rudimentary

nictitating membrane The nictitating membrane (from Latin '' nictare'', to blink) is a transparent or translucent third eyelid present in some animals that can be drawn across the eye from the medial canthus to protect and moisten it while maintaining vision. All An ...

s (protective third eyelids). Beneath each eye is a prominent ridge, and behind is a tiny

spiracle Spiracle or spiraculum may refer to: * Spiracle (arthropods), opening in the exoskeletons of some arthropods * Spiracle (vertebrates), openings on the surface of some vertebrates * Spiraculum ''Spiraculum'' is a genus of operculate land snail ...

. The anterior rims of the nostrils bear triangular flaps of skin. The mouth is fairly large and wide, and is broadly arched. There are long, well-developed furrows that wrap around each corner of the mouth. The tooth rows number around 60 in either jaw; the teeth have a narrow central cusp flanked by 1–2 pairs of smaller cusplets. There are 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 co ...

s. 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 c ...

s vary in shape, with the first is marginally larger than the second. The first dorsal fin originates over the posterior half of 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 e ...

s, while the second originates over the middle of 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 s ...

. 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 ...

s are fairly large and wide, with rounded tips. The pelvic fins are short and low; adult males have characteristically long, thin

measuring roughly 10–11% of the total length. The anal fin is relatively small, with its base measuring 8–10% of the total length. The

is long, with a small lower lobe and a deep ventral notch near the tip of the upper lobe. The

s are small and overlapping, each with a median ridge and three marginal teeth on the crown. An elevated, saw-like crest of enlarged denticles is present along the front half of the dorsal caudal fin edge. This species is a variable shade of gray above, with a dark saddle intersecting the front half of each dorsal fin, and two more saddles along the tail. The leading margins of the pectoral fins are distinctly black, while the trailing margins of the dorsal and anal fins are whitish. The underside is pale and unmarked. The interior lining of the mouth is blackish on the roof and white elsewhere.

Biology and ecology

Little is known of the natural history of ''G. priapus''. Males attain

sexual maturity Sexual maturity is the capability of an organism to reproduce. In humans it might be considered synonymous with adulthood, but here puberty is the name for the process of biological sexual maturation, while adulthood is based on cultural definit ...

at around long.

Human interactions

''G. priapus'' has been evaluated as

Least Concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. Th ...

by the

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natur ...

(IUCN).

References

{{Taxonbar, from=Q1949667 phallic catshark Fish of New Caledonia Fauna of Vanuatu phallic catshark Taxa named by Bernard Séret Taxa named by Peter R. Last