The peppered catshark (''Galeus piperatus'') is a common but little-known

species In biology, a species is the basic unit of 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 the appropriate s ...

of catshark, 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 ...

Scyliorhinidae, inhabiting depths of in the northern

Gulf of California The Gulf of California ( es, Golfo de California), also known as the Sea of Cortés (''Mar de Cortés'') or Sea of Cortez, or less commonly as the Vermilion Sea (''Mar Bermejo''), is a marginal sea of the Pacific Ocean that separates the Baja Ca ...

. It is found on or near the ocean floor, and conducts seasonal migrations, spending winter in deeper water. Reaching a length of , this species has a slender grayish body with a fine covering of black dots. On the dorsal edge of its

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 ...

is a prominent 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 we ...

s. It is

oviparous Oviparous animals are animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive method of most fish, amphibians, most reptiles, and all pterosaurs, dinosaurs (including birds), and ...

, with the reproductive period probably lasting from May to September. 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 natu ...

(IUCN) has listed the peppered catshark under

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. T ...

, as it faces no significant threats from human activity.

Taxonomy

The peppered catshark was described by

Stewart Springer Stewart Springer (5 June 190623 August 1991) was an American ichthyologist and herpetologist. He was a world-renowned expert on shark behavior, classification (taxonomy), and population distribution. More than 35 species of sharks, skates, rays, ...

and Mary Wagner in a 1966 issue of ''Los Angeles County Museum Contributions in Science''; 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 ...

''piperatus'' is derived from the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

''piper'', meaning "pepper". The

type specimen In biology, a type is a particular wiktionary:en:specimen, 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 a ...

is an adult female long, collected halfway between

Tiburón Island Tiburón Island is the largest island in the Gulf of California and the largest island in Mexico, with an area of . It was made a nature reserve in 1963 by President Adolfo López Mateos. Etymology is Spanish for 'shark'. Although the Seri nam ...

and

Isla Ángel de la Guarda Isla Ángel de la Guarda, (Guardian Angel Island) also called Archangel Island, is a large island in the Gulf of California (Sea of Cortez) east of Bahía de los Ángeles in northwestern Mexico, separated from the Baja California Peninsula by the ...

. The peppered catshark is barely distinguishable from the '' G. arae'' species complex of the western

Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...

; its anomalous geographical distribution is likely a product of

vicariance Allopatric speciation () – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from ...

stemming from the formation of the

Isthmus of Panama The Isthmus of Panama ( es, Istmo de Panamá), also historically known as the Isthmus of Darien (), is the narrow strip of land that lies between the Caribbean Sea and the Pacific Ocean, linking North and South America. It contains the country ...

(''c.'' 3 Ma).

Distribution and habitat

The range of the peppered catshark is limited to the

, with the southern boundary defined by the city of Guaymas in

Sonora Sonora (), officially Estado Libre y Soberano de Sonora ( en, Free and Sovereign State of Sonora), is one of the 31 states which, along with Mexico City, comprise the Administrative divisions of Mexico, Federal Entities of Mexico. The state is d ...

, and Isla Salsipuedes in

Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...

. This abundant species has been recorded from between deep, but is most common at a depth of . Though main

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 ...

in habits, at night it has been captured as much as above the bottom. At the northern extreme of the Gulf of California, this species virtually disappears during the summer, suggesting that it overwinters in deeper, more southerly waters. This migration is unusual in that it is opposite pattern observed in most other migratory fishes of the Gulf, and seems to be correlated with reproductive activity with spawning taking place in the summer.

Description

The maximum known length attained by the peppered catshark is . This species is slender and firm-bodied, with a slightly flattened head and a rather long, pointed snout. The anterior rims of the nostrils are expanded into triangular flaps of skin. The horizontally oval eyes are 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 ...

s (protective third eyelids), and lack obvious ridges underneath. Behind each eye is a minute

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, a genus of land snails in family Cyclophoridae Cycl ...

. The large mouth is wide and curved, with well-developed furrows at the corners. The teeth have narrow central cusps flanked by up to three pairs of cusplets on either side. 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 con ...

s. The first and second

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 ...

s originate over the rear 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 en ...

s and 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 se ...

respectively. The dorsal fins are similar in shape and size, both having blunt apexes. 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 large and broad, with rounded corners. The pelvic and anal fins are rather small and low, with angular corners. The anal fin base measures around 11–13% of the total length, comparable to the distance between the dorsal fins and greatly exceeding the distance between the pelvic and anal fins. The caudal peduncle is compressed from side to side and leads to a low

, which has a small lower lobe and a ventral notch near the tip of the upper lobe. The

s are small and overlapping, each with a leaf-shaped crown bearing a median ridge and three marginal teeth. There is a saw-like crest of enlarged denticles along the anterior portion of the upper caudal fin margin. The body and tail are dusky with a covering of fine black dots; young sharks may also have a series of darker brown saddle markings outlined in white. The caudal fin margin is white, and the inside of the mouth is typically blackish.

Biology and ecology

Little is known of the natural history of the peppered catshark. Reproduction is

and apparently takes place between May and September. Newly mature females carry only 2–3 eggs, while the largest females may carry 10 or more eggs at a time; each egg is contained within a distinctively olive-green capsule around long. The egg cases are consumed by the

Pacific angelshark The Pacific angelshark (''Squatina californica'') is a species of angelshark, family Squatinidae, found in the eastern Pacific Ocean from Alaska to the Gulf of California, and from Ecuador to Chile, although those in the Gulf of California and so ...

(''Squatina california''). The young sharks hatch at a length of . Mathews (1984) reported females maturing at a length of , while Compagno (1984) reported males and females maturing at lengths of and respectively.

Human interactions

The peppered catshark generally lives beyond the depths utilized by commercial fisheries in the Gulf of California. As a result, the

(IUCN) has assessed it as of

References

{{Taxonbar, from=Q748262 peppered catshark Fish of the Gulf of California peppered catshark