Northern sawtail catshark
Encyclopedia
The northern sawtail catshark (Figaro striatus) is a little-known species
of catshark
, family
Scyliorhinidae, endemic to northeastern Australia
. It is demersal in nature and inhabits the upper continental slope at a depth of 300–420 m (984.3–1,378 ft). A small, slender species growing no longer than 42 cm (16.5 in), the northern sawtail catshark is characterized by a series of dark, narrow saddles along its back and tail, and rows of prominently enlarged dermal denticles along the upper edge of its caudal fin and the underside of its caudal peduncle. The International Union for Conservation of Nature (IUCN) does not yet have enough information to assess its conservation status.
(CSIRO) publication, in which they also resurrected the genus Figaro, until then considered a junior synonym of Galeus. The specific epithet striatus means "striped" in Latin
. The type specimen is a 42 cm (16.5 in) long adult male caught south of the Saumarez Reefs
, Queensland
, on November 17, 1985.
and Townsville. It is found on or near the bottom at a depth of 300–420 m (984.3–1,378 ft).
s (protective third eyelids); beneath each is a narrow ridge, and behind is a tiny spiracle
. The anterior rims of the nostrils are enlarged into triangular, outward-pointing flaps. The mouth is large and arched, with short but prominent furrows around each corner. There are around 65 upper and 61–65 lower tooth rows; each tooth has a narrow central cusp flanked by 3–5 smaller cusplets. There are five pairs of gill slit
s; the fourth and fifth are located over the pectoral fin bases and closer together than the others.
The small dorsal fin
s have blunt apexes and straight to gently convex trailing margins; the first is slightly taller but shorter-based than the second. The origin of the first and second dorsal fins lie over the rear of the pelvic fins and anal fin respectively. The pectoral fins are small and broad, with rounded corners. The pelvic fins are long and low; adult males have slender claspers and a slight "apron" formed from the fusion of the pelvic fin inner margins. The anal fin is elongated, its base measuring roughly a tenth of the total length, and rather angular. The length of the anal fin base exceeds the distance between the anal and pelvic fins, and is comparable to the distance between the dorsal fins. The caudal fin is short and low, with a small lower lobe and a ventral notch near the tip of the upper lobe. The body and fins are entirely covered by minute, overlapping dermal denticles; each has an ovoid crown with a horizontal ridge leading to a marginal cusp. There are distinctive crests of enlarged, spiny denticles along the anterior half of the caudal fin upper margin, and beneath the caudal peduncle. This species is light grayish brown on the back of the body and tail, with a series of dark brown saddles numbering 10–16 before the dorsal fins, of which a few are wider than the others. The flanks, underside, and fins are whitish.
at approximately 38 cm (15 in) long.
.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of catshark
Catshark
Catsharks are ground sharks of the family Scyliorhinidae, with over 150 known species. While they are generally known as catsharks, many species are commonly called dogfish....
, family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Scyliorhinidae, endemic to northeastern Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. It is demersal in nature and inhabits the upper continental slope at a depth of 300–420 m (984.3–1,378 ft). A small, slender species growing no longer than 42 cm (16.5 in), the northern sawtail catshark is characterized by a series of dark, narrow saddles along its back and tail, and rows of prominently enlarged dermal denticles along the upper edge of its caudal fin and the underside of its caudal peduncle. The International Union for Conservation of Nature (IUCN) does not yet have enough information to assess its conservation status.
Taxonomy
The first known specimens of the northern sawtail catshark were collected during exploratory surveys conducted off northeastern Australia in the 1980s, and provisionally termed Galeus sp. B. It was formally described by Daniel Gledhill, Peter Last, and William White in a 2008 Commonwealth Scientific and Industrial Research OrganisationCommonwealth Scientific and Industrial Research Organisation
The Commonwealth Scientific and Industrial Research Organisation is the national government body for scientific research in Australia...
(CSIRO) publication, in which they also resurrected the genus Figaro, until then considered a junior synonym of Galeus. The specific epithet striatus means "striped" in Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
. The type specimen is a 42 cm (16.5 in) long adult male caught south of the Saumarez Reefs
Saumarez Reefs
Saumarez Reefs is one of the southernmost reefs to be located in the Coral Sea Islands and part of the Coral Sea Shelf; it contains three main reefs and numerous smaller reefs all of which form a large crescent-shaped formation open to the northwest, about 27 by 14 km, area less than 300 km².There...
, Queensland
Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
, on November 17, 1985.
Distribution and habitat
The range of the northern sawtail catshark is limited to the upper continental slope off Queensland, between RockhamptonRockhampton
Rockhampton can refer to:* Rockhampton, Queensland is a city in Queensland, Australia* Rockhampton City, Queensland, a suburb of Rockhampton, Queensland* Electoral district of Rockhampton, Queensland, Australia...
and Townsville. It is found on or near the bottom at a depth of 300–420 m (984.3–1,378 ft).
Description
Reaching 42 cm (16.5 in) in length, the northern sawtail catshark has a firm, thin body with a mostly cylindrical cross-section. The head is short, narrow, and flattened, with a bluntly pointed snout. The eyes are horizontally oval and equipped with rudimentary nictitating membraneNictitating membrane
The nictitating membrane is a transparent or translucent third eyelid present in some animals that can be drawn across the eye for protection and to moisten it while maintaining visibility. Some reptiles, birds, and sharks have a full nictitating membrane; in many mammals, there is a small...
s (protective third eyelids); beneath each is a narrow ridge, and behind is a tiny spiracle
Spiracle
Spiracles are openings on the surface of some animals that usually lead to respiratory systems.-Vertebrates:The spiracle is a small hole behind each eye that opens to the mouth in some fishes. In the primitive jawless fish the first gill opening immediately behind the mouth is essentially similar...
. The anterior rims of the nostrils are enlarged into triangular, outward-pointing flaps. The mouth is large and arched, with short but prominent furrows around each corner. There are around 65 upper and 61–65 lower tooth rows; each tooth has a narrow central cusp flanked by 3–5 smaller cusplets. There are five pairs of gill slit
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, rays, sawfish, and guitarfish. Most of these have five pairs, but a few species have 6 or 7 pairs...
s; the fourth and fifth are located over the pectoral fin bases and closer together than the others.
The small dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
s have blunt apexes and straight to gently convex trailing margins; the first is slightly taller but shorter-based than the second. The origin of the first and second dorsal fins lie over the rear of the pelvic fins and anal fin respectively. The pectoral fins are small and broad, with rounded corners. The pelvic fins are long and low; adult males have slender claspers and a slight "apron" formed from the fusion of the pelvic fin inner margins. The anal fin is elongated, its base measuring roughly a tenth of the total length, and rather angular. The length of the anal fin base exceeds the distance between the anal and pelvic fins, and is comparable to the distance between the dorsal fins. The caudal fin is short and low, with a small lower lobe and a ventral notch near the tip of the upper lobe. The body and fins are entirely covered by minute, overlapping dermal denticles; each has an ovoid crown with a horizontal ridge leading to a marginal cusp. There are distinctive crests of enlarged, spiny denticles along the anterior half of the caudal fin upper margin, and beneath the caudal peduncle. This species is light grayish brown on the back of the body and tail, with a series of dark brown saddles numbering 10–16 before the dorsal fins, of which a few are wider than the others. The flanks, underside, and fins are whitish.
Biology and ecology
Little is known of the natural history of the northern sawtail catshark. Males attain sexual maturitySexual maturity
Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...
at approximately 38 cm (15 in) long.
Human interactions
The International Union for Conservation of Nature has noted that there is minimal fishing activity within the northern sawtail catshark's range, but presently lacks sufficient information to assess it beyond Data DeficientData Deficient
Data Deficient is a category applied by the IUCN, other agencies, and individuals to a species when the available information is not sufficient for a proper assessment of conservation status to be made...
.