The roughtail catshark or marbled catshark (''Galeus arae'') is a common

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 ...

, part of 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 at a depth of in the northwestern

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

, the

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United S ...

, and the

Caribbean Sea The Caribbean Sea ( es, Mar Caribe; french: Mer des Caraïbes; ht, Lanmè Karayib; jam, Kiaribiyan Sii; nl, Caraïbische Zee; pap, Laman Karibe) is a sea of the Atlantic Ocean in the tropics of the Western Hemisphere. It is bounded by Mexico ...

, from

North Carolina North Carolina () is a state in the Southeastern region of the United States. The state is the 28th largest and 9th-most populous of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, Georgia a ...

to Costa Rica. Individuals of different sexes and ages are segregated to some degree. A small species not exceeding in length, the roughtail catshark has a slender body with a marbled color pattern of dark saddles and spots, and 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 w ...

s along 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 s ...

. This species feeds mainly on

shrimp Shrimp are crustaceans (a form of shellfish) with elongated bodies and a primarily swimming mode of locomotion – most commonly Caridea and Dendrobranchiata of the decapod order, although some crustaceans outside of this order are refer ...

and 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), a ...

. It is caught incidentally in shrimp

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 ...

s, though trawl fisheries within its range mostly do not operate at the depths it inhabits. As a result, 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 ...

has listed it 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. Th ...

Taxonomy

John T. Nichols of the American Museum of Natural History originally described the roughtail catshark as ''Pristiurus arae'' in a 1927 issue of ''American Museum Novitates''. He named the species after the

er ''Ara'', which collected the first two specimens, both long immature females, off

Miami Beach Miami Beach is a coastal resort city in Miami-Dade County, Florida. It was incorporated on March 26, 1915. The municipality is located on natural and man-made barrier islands between the Atlantic Ocean and Biscayne Bay, the latter of which s ...

on March 31, 1926. Later authors have recognized ''Pristiurus'' as a junior synonym of ''

Galeus ''Galeus'' is a genus of catshark, belonging to the family Scyliorhinidae, commonly known as sawtail catsharks in reference to a distinctive saw-toothed crest of enlarged dermal denticles, found along the upper edges of their caudal fins. They a ...

''. The

Antilles catshark The Antilles catshark (''Galeus antillensis'') is a common but little-known species of catshark, part of the family Scyliorhinidae. It is found on or near the bottom at a depth of off Florida and the West Indies from Jamaica to Martiniqu ...

(''G. antillensis'') and the

longfin sawtail catshark The longfin sawtail catshark (''Galeus cadenati'') is a rare, little-known species of catshark, part of the family Scyliorhinidae. Once thought to be a subspecies of the roughtail catshark (''G. arae'') along with the Antilles catshark (''G ...

(''G. cadenati'') were regarded as subspecies of ''G. arae'', until taxonomic revisions were published by Hera Konstantinou and colleagues in 1998 and 2000. The three species, along with the

southern Southern may refer to: Businesses * China Southern Airlines, airline based in Guangzhou, China * Southern Airways, defunct US airline * Southern Air, air cargo transportation company based in Norwalk, Connecticut, US * Southern Airways Express, M ...

and Springer's sawtail catsharks (''G. mincaronei'' and ''G. springeri''), are grouped together in the ''G. arae''

species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

Description

Probably the smallest member of the ''G. arae'' species complex, the roughtail catshark grows no longer than . It has a slender, firm body and a slightly flattened head. The snout is rather long and pointed, with the nostrils divided by triangular skin flaps in front. 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 An ...

s (protective third eyelids), and lack prominent ridges underneath. There is a tiny spiracle behind each eye. The mouth is large and forms a broad arch, with moderately long furrows around the corners. The teeth are small and number 59–65 rows in the upper jaw and 58–60 rows in the lower jaw. Each tooth has a thin central cusp flanked by 1–3 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 co ...

s. The first

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 ...

has a blunt apex and is positioned over the latter 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 ...

bases. The second dorsal fin is nearly as large as the first and similar in shape, and positioned over the latter half 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 ...

base. The large, broad

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 have rounded corners. The pelvic and anal fins are low and angular. The anal fin base measures roughly 10–14% of the total length, exceeding the distance between the pelvic and anal fins and about the same as the distance between the dorsal fins. The

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

s are small and overlapping; each has a leaf-shaped crown with a horizontal ridge and three marginal teeth. There is a prominent saw-toothed crest, formed from enlarged denticles, along the anterior portion of the dorsal caudal fin margin. This species is yellowish brown above with a marbled color pattern consisting of usually fewer than 11 dark saddles along the back and tail. Some smaller sharks have markings that form horizontal lines, while some larger sharks have round blotches along the sides. These markings can range from faint to well-defined by white outlines. The underside is pale, and the inside of the mouth is black.

Distribution and habitat

While the full extent of its range may remain to be documented, the roughtail catshark seems to have a

disjunct distribution In biology, a taxon with a disjunct distribution is one that has two or more groups that are related but considerably separated from each other geographically. The causes are varied and might demonstrate either the expansion or contraction of a s ...

that does not overlap with that of either ''G. antillensis'' or ''G. cadenati''. The northern population occurs from

southward to the Caribbean and the Yucatan Peninsula, and westward to the

Mississippi River Delta The Mississippi River Delta is the confluence of the Mississippi River with the Gulf of Mexico in Louisiana, southeastern United States. The river delta is a area of land that stretches from Vermilion Bay on the west, to the Chandeleur Is ...

. The southern population is found in the

off the coasts of Honduras,

Nicaragua Nicaragua (; ), officially the Republic of Nicaragua (), is the largest Sovereign state, country in Central America, bordered by Honduras to the north, the Caribbean Sea, Caribbean to the east, Costa Rica to the south, and the Pacific Ocean to ...

, and Costa Rica. The roughtail catshark 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 laye ...

species typically inhabiting continental and insular slopes, occasionally venturing onto the shelf. It is abundant but unevenly distributed, with some areas harboring hundreds of sharks and other areas none at all. Sharks of the northern population have been recorded from depths of , and those of the southern population from . The shallowest records have tended to come from higher

latitude In geography, latitude is a coordinate that specifies the north– south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from –90° at the south pole to 90° at the north po ...

s, suggesting that temperature plays more of a role than depth in determining the species' distribution; it has been captured from water ranging from . Both adults and juveniles occur up to a depth of , while usually only adults are found deeper. There also appears to be spatial segregation by sex, though the patterns are not well-defined.

Biology and ecology

The roughtail catshark preys mostly on

, and may gather in sizable

schools A school is an educational institution designed to provide learning spaces and learning environments for the teaching of students under the direction of teachers. Most countries have systems of formal education, which is sometimes compul ...

. Once erroneously reported to be

aplacental viviparous Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a term used as a "bridging" form of reproduction between egg-laying oviparous and live-bearing viviparous reproduction. Ovoviviparous animals possess embryos that develop insi ...

, more recent research has confirmed that this species is actually

. Adult females have a single functional

ovary The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the bod ...

, on the right, and two functional

oviduct The oviduct in mammals, is the passageway from an ovary. In human females this is more usually known as the Fallopian tube or uterine tube. The eggs travel along the oviduct. These eggs will either be fertilized by spermatozoa to become a zygote, ...

s. A single egg matures within each oviduct at a time. The eggs are enclosed within tough, flask-shaped capsules around long, across the top, and across the bottom. The rounded upper corners of the capsule bear coiled tendrils. The spawning grounds of this shark may be located in very rough terrain. Both sexes

mature sexually 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 definiti ...

at approximately long.

Human interactions

Harmless and of no commercial value, the roughtail catshark is too small to be caught on most types of fishing gear but is taken incidentally in shrimp

s. Shark expert

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, ...

reported in 1966 that it was frequently caught in shrimp trawls along the entire coast of Florida. The impact of trawl fisheries on this species in United States waters is unknown; its depth and spawning habitat preferences may offer a degree of protection from fishing pressure. Similarly, shrimp trawling activity off Central America does not extend into the depths occupied by this species. The

(IUCN) has therefore assessed the roughtail catshark as of

References

{{Taxonbar, from=Q2719410 roughtail catshark Fauna of the Southeastern United States Fish of the Caribbean Fish of the Dominican Republic Taxa named by John Treadwell Nichols roughtail catshark