Springer's sawtail catshark (''Galeus springeri'') is a

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, found in waters deep off the islands of the

Antilles The Antilles (; gcf, label=Antillean Creole, Antiy; es, Antillas; french: Antilles; nl, Antillen; ht, Antiy; pap, Antias; Jamaican Patois: ''Antiliiz'') is an archipelago bordered by the Caribbean Sea to the south and west, the Gulf of Mex ...

, from

Cuba Cuba ( , ), officially the Republic of Cuba ( es, República de Cuba, links=no ), is an island country comprising the island of Cuba, as well as Isla de la Juventud and several minor archipelagos. Cuba is located where the northern Caribbea ...

to the

Leewards french: Îles-Sous-le-Vent , image_name = , image_caption = ''Political'' Leeward Islands. Clockwise: Antigua and Barbuda, Guadeloupe, Saint kitts and Nevis. , image_alt = , locator_map = , location = Caribbean SeaNorth Atlantic Ocean , coor ...

. A small, slim-bodied species reaching a length of , the Springer's sawtail catshark can be identified by its color pattern of horizontal dark stripes in front of the first dorsal fin, and dark dorsal saddles behind. It is additionally characterized by the presence of saw-toothed crests, made 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 both the dorsal and the ventral edges of the

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 ...

. The Springer's sawtail catshark 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 ...

Taxonomy

The Springer's sawtail catshark was originally regarded as the striped

color morph In biology, polymorphism is the occurrence of two or more clearly different morphs or forms, also referred to as alternative ''phenotypes'', in the population of a species. To be classified as such, morphs must occupy the same habitat at the s ...

of 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'', formerly ''G. arae antillensis''). The first known specimen had resided in the

National Museum of Natural History The National Museum of Natural History is a natural history museum administered by the Smithsonian Institution, located on the National Mall in Washington, D.C., United States. It has free admission and is open 364 days a year. In 2021, with ...

for over 20 years, until an artifact of preservation revealed the distinctive ventral

crest on the

. The species was described in a 1998 issue 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 ...

''Copeia'' by Hera Konstantinou and Joseph Cozzi, who named it after leading shark taxonomist

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, ...

. 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 immature male collected on December 8, 1969 near the Leeward Islands. This shark belongs to 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 ...

, which also includes ''G. antillensis'', '' G. arae'', '' G. cadenati'', and '' G. mincaronei''.

Distribution and habitat

The range of the Springer's sawtail catshark is limited and overlaps that of the similar Antilles catshark; it occurs off

Jamaica Jamaica (; ) is an island country situated in the Caribbean Sea. Spanning in area, it is the third-largest island of the Greater Antilles and the Caribbean (after Cuba and Hispaniola). Jamaica lies about south of Cuba, and west of Hispan ...

Hispaniola Hispaniola (, also ; es, La Española; Latin and french: Hispaniola; ht, Ispayola; tnq, Ayiti or Quisqueya) is an island in the Caribbean that is part of the Greater Antilles. Hispaniola is the most populous island in the West Indies, and t ...

Puerto Rico Puerto Rico (; abbreviated PR; tnq, Boriken, ''Borinquen''), officially the Commonwealth of Puerto Rico ( es, link=yes, Estado Libre Asociado de Puerto Rico, lit=Free Associated State of Puerto Rico), is a Caribbean island and Unincorporated ...

, the Leeward Islands, and probably the U.S. Virgin Islands. The full extent of its distribution is uncertain due to confusion with related species. Recorded from depths of , this species is found on or near the bottom over upper continental and insular slopes.

Description

The largest known specimen of the Springer's sawtail catshark measured long. It has a slender body and a somewhat flattened head with a long, pointed snout. The eyes are horizontally oval 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); they are followed by tiny spiracles and lack prominent ridges underneath. The nostrils are divided by triangular flaps of skin on their anterior rims. The large mouth forms a wide arch, and bears moderately long furrows at the corners. The teeth are small and have a narrow central cusp flanked by multiple cusplets; they are similar in both jaws, and between sexes. 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 placed over the aft part 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. The second dorsal fin is similar in shape and nearly equal in size to the first, and placed over the aft part 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 broad. The small pelvic fins are low relative to their bases, and have angular margins. The anal fin is elongated and placed close to the pelvic and

s; the anal fin base measures 11% of the total length, about comparable to the space between the dorsal fins. The caudal fin has a small lower lobe and a ventral notch near the tip of the upper lobe. The body is covered by small, overlapping

s, each with a teardrop-shaped crown with a median ridge and three marginal teeth. There are enlarged denticles forming distinctive saw-like crests along the anterior portions of both the dorsal and ventral caudal fin edges. This species has a unique dorsal color pattern, consisting of dark horizontal stripes outlined in white in front of the dorsal fins, and a series of dark saddle-like markings running from the first dorsal fin base to the tail, on a dusky background. The underside is uniformly white.

Biology and ecology

There is little known of the natural history of the Springer's sawtail catshark. Reproduction is presumably

; other females of the ''G. arae'' complex produce flask-shaped egg capsules around long, with tendrils at the upper two corners. Adult males have yet to be captured; the largest immature male measured long. Females are

mature Mature is the adjectival form of maturity, as immature is the adjectival form of immaturity, which have several meanings. Mature or immature may also refer to: * Mature, a character from ''The King of Fighters'' series *"Mature 17+", a rating in ...

by a length of .

Human interactions

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 the Springer's sawtail catshark as least concern. Given its restricted range, it may be negatively affected by any expansion of deepwater fisheries in the region. It is occasionally caught in

bottom trawl Bottom trawling is trawling (towing a trawl, which is a fishing net) along the seafloor. It is also referred to as "dragging". The scientific community divides bottom trawling into benthic trawling and demersal trawling. Benthic trawling is towing ...

References

{{Taxonbar, from=Q1950250 Springer's sawtail catshark Fish of the Caribbean Fish of the Dominican Republic Springer's sawtail catshark