The Australian swellshark (''Cephaloscyllium laticeps'') or draughtboard shark, is a

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 ...

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 ...

, and 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,

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to southern

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

. This bottom-dwelling species can be found on the

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island ...

down to a depth of . Usually measuring long, it is a stout-bodied, broad-headed shark with a short tail and a 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 conv ...

much larger than the second. It can be identified by its variegated dorsal coloration of brown or grey patches and numerous spots. Australian swellsharks are sedentary and mainly

nocturnal Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...

, with most individuals remaining within the same local area throughout the year. It feeds on small

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

cephalopod A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head ...

s, and

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

. When threatened, it responds by rapidly taking in water or air to inflate its body, hence the name "swellshark". This shark 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 ...

and females lay pairs of distinctively ridged egg capsules at 20- to 30-day intervals. The eggs hatch after 11–12 months. Harmless and of little commercial interest, many Australian swellsharks are caught incidentally in gillnets and

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 tow ...

s but usually survive to be released because of their extreme hardiness. 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 natu ...

(IUCN) has assessed this species as of

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 ...

Taxonomy

The first scientific description of the Australian swellshark, as ''Scyllium laticeps'', was published in 1853 by French

zoologist Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the Animal, animal kingdom, including the anatomy, structure, embryology, evolution, Biological clas ...

Auguste Duméril Auguste Henri André Duméril (30 November 1812 – 12 November 1870) was a French zoologist. His father, André Marie Constant Duméril (1774-1860), was also a zoologist. In 1869 he was elected as a member of the Académie des sciences. Duméril ...

, in 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 as s ...

''Revue et Magasin de Zoologie''. 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 ...

was a male caught off

Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...

. 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 ...

''laticeps'' 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 ...

''latus'', meaning "broad", with the suffix ''ceps'', meaning "head".Bester, C
Biological Profiles: Australian Swellshark
Florida Museum of Natural History Ichthyology Department. Retrieved on 7 September 2009. Other

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...

s for this species include flopguts (a reference to its ability to inflate), Isabell's swell shark, nutcracker shark, rock shark, sleepy Joe, and spotted swellshark. This species is almost identical to the

draughtsboard shark The draughtsboard shark (''Cephaloscyllium isabellum'') is a species of catshark, and part of the family (biology), family Catshark, Scyliorhinidae, so named for its "checkerboard" color pattern of dark blotches. It is Endemism, endemic to New ...

(''C. isabellum'') of

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

; the two species differ in coloration and the form of their egg cases (ridged in ''C. laticeps'' versus smooth in ''C. isabellum'').

Description

The Australian swellshark has a stocky, rounded body that tapers significantly to the short

caudal peduncle 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 ...

. The head comprises no more than a fifth of the total length and is broad and moderately flattened, with a very short, thick, blunt snout. The

nostril A nostril (or naris , plural ''nares'' ) is either of the two orifices of the nose. They enable the entry and exit of air and other gasses through the nasal cavities. In birds and mammals, they contain branched bones or cartilages called turbi ...

s are divided into small incurrent and excurrent openings by short, triangular flaps of skin that do not reach the mouth. The mouth is extremely large, without furrows at the corners. The teeth are numerous and small with multiple cusps; the upper teeth are exposed when the mouth is closed. The large, oval eyes are placed somewhat on the upper surface of the head, and have 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

eyelid An eyelid is a thin fold of skin that covers and protects an eye. The levator palpebrae superioris muscle retracts the eyelid, exposing the cornea to the outside, giving vision. This can be either voluntarily or involuntarily. The human eyel ...

s) and ridges underneath. There are two

s, the first much larger than the second. The first dorsal originates over the forward 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 en ...

bases, while the second is located over 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 ...

. 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, and the anal fin is larger than the second dorsal fin. The short and broad

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 ...

has an indistinct lower lobe and a prominent ventral notch near the tip of the upper lobe. The skin is thick and covered by well-

calcified Calcification is the accumulation of calcium salts in a body tissue. It normally occurs in the formation of bone, but calcium can be deposited abnormally in soft tissue,Miller, J. D. Cardiovascular calcification: Orbicular origins. ''Nature Mat ...

arrowhead An arrowhead or point is the usually sharpened and hardened tip of an arrow, which contributes a majority of the projectile mass and is responsible for impacting and penetrating a target, as well as to fulfill some special purposes such as sign ...

-shaped dermal denticles, which are more sparse in young sharks. The back and sides are light grey to brown, with an irregular pattern of close-set darker saddles and blotches along with many dark (sometimes light) spots, and a dark stripe from under the eye to the pectoral fin origins. The fins do not have sharply lighter margins. The underside is cream-coloured, with some mottling on the fins and often a dark stripe running down the middle in adults. The maximum known length is , though few exceed .

Distribution and habitat

The Australian swellshark inhabits the continental shelf of southern Australia, from the

Recherche Archipelago The Archipelago of the Recherche, known locally as the Bay of Isles, is a group of 105 islands, and over 1200 "obstacles to shipping", off the south coast of Western Australia. The islands stretch from east to west and to off-shore encom ...

off

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

Jervis Bay Jervis Bay () is a oceanic bay and village on the south coast of New South Wales, Australia, said to possess the whitest sand in the world. A area of land around the southern headland of the bay is a territory of the Commonwealth of Australia ...

New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...

, including Tasmania. It is commonly found on or near the bottom amongst rocky

reef A reef is a ridge or shoal of rock, coral or similar relatively stable material, lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic processes— deposition of sand, wave erosion planing down rock out ...

s or

seaweed Seaweed, or macroalgae, refers to thousands of species of macroscopic, multicellular, marine algae. The term includes some types of '' Rhodophyta'' (red), ''Phaeophyta'' (brown) and ''Chlorophyta'' (green) macroalgae. Seaweed species such as ...

beds, from close to shore to a depth of .

Biology and ecology

The most abundant catshark species in the coastal waters of southern Australia, the Australian swellshark is a generally sluggish swimmer that is more active at night. During the day, it is often found resting singly or in groups under ledges or inside caves. Tracking studies have shown that some individuals are continuously active for months at a time, while others alternate activity with periods of stationary rest lasting up to five days. Most Australian swellsharks present within a given region tend to remain there year-round, frequenting established feeding areas or preferred habitats. On the other hand, a minority of sharks have been recorded covering distances of up to . This extremely hardy species can survive for more than a day out of water. One of the higher-level

predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

s within its

ecosystem An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...

, the Australian swellshark feeds on

s (particularly

crab Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the ...

s and

rock lobster "Rock Lobster" is a song written by Fred Schneider and Ricky Wilson, two members of the B-52's. It was twice recorded and released as a single, first by DB Records as their debut release in April 1978, and again the following year for the b ...

s),

s (including

squid True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fitting t ...

and

octopus An octopus ( : octopuses or octopodes, see below for variants) is a soft-bodied, eight- limbed mollusc of the order Octopoda (, ). The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttle ...

), and small

es. Even large-sized prey tends to be swallowed whole; the long periods of rest exhibited by some sharks may relate to

digestion Digestion is the breakdown of large insoluble food molecules into small water-soluble food molecules so that they can be absorbed into the watery blood plasma. In certain organisms, these smaller substances are absorbed through the small intest ...

. Like the other members of its genus, this shark is capable of rapidly inflating its body by taking water or air into its

stomach The stomach is a muscular, hollow organ in the gastrointestinal tract of humans and many other animals, including several invertebrates. The stomach has a dilated structure and functions as a vital organ in the digestive system. The stomach i ...

, as a defense against

s. These include larger fishes, such as the

broadnose sevengill shark The broadnose sevengill shark (''Notorynchus cepedianus'') is the only extant member of the genus ''Notorynchus'', in the family Hexanchidae. It is recognizable because of its seven gill slits, while most shark species have five gill slits, with ...

(''Notorynchus cepedianus''), and

marine mammal Marine mammals are aquatic mammals that rely on the ocean and other marine ecosystems for their existence. They include animals such as seals, whales, manatees, sea otters and polar bears. They are an informal group, unified only by their reli ...

s. By inflating, the shark may be able to wedge itself inside crevices, make itself harder to swallow, or simply intimidate a would-be predator. Marine snails are known to prey upon this shark's eggs. The Australian swellshark serves as a host to a number of

parasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...

species, but these are poorly documented.

Life history

The Australian swellshark is

. Males have larger teeth than females, with which to bite and hold onto them for

copulation Sexual intercourse (or coitus or copulation) is a sexual activity typically involving the insertion and thrusting of the penis into the vagina for sexual pleasure or reproduction.Sexual intercourse most commonly means penile–vaginal penetra ...

. Whether there is a specific

mating season Seasonal breeders are animal species that successfully mate only during certain times of the year. These times of year allow for the optimization of survival of young due to factors such as ambient temperature, food and water availability, and ch ...

is uncertain, though in terms of

sperm Sperm is the male reproductive cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm with a tail known as a flagellum, whi ...

production males are capable of breeding year-round. 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 body. ...

and two

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, o ...

s, ovulating a single egg into each at a time. They can store sperm for at least 15 months. Females produce eggs throughout the year, laying them in pairs approximately once every 20 days from January to June, and once every 30 days the rest of the year. The second egg in a pair is deposited 12–24 hours after the first. The pale, flask-shaped egg capsules measure long and across, and bear 19–27 crosswise ridges. There are long, curling tendrils at the four corners, which allow the female to attach the capsule to seaweed or other bottom structures. In captivity, the

embryo An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...

develops external gills at two months old, which are retained until it is five months old, at which time the internal gills take over and the first

pigment A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compo ...

ation appears. At six months, embryonic growth accelerates and the

yolk sac The yolk sac is a membranous sac attached to an embryo, formed by cells of the hypoblast layer of the bilaminar embryonic disc. This is alternatively called the umbilical vesicle by the Terminologia Embryologica (TE), though ''yolk sac'' is far ...

begins to shrink, disappearing by nine to ten months of age. Hatching usually occurs at eleven to twelve months; the newly emerged young are miniature versions of the adults measuring long.Marsh, N. (15 August 2007)
"A Swell Little Aussie Shark"
. ''Shark Diver Magazine'' 15. Retrieved on 7 September 2009. Males mature sexually at a length of , and females at .

Human interactions

The Australian swellshark is harmless to humans and seldom utilised, though recently in parts of Tasmania some have begun to be marketed as a source of "

flake Flake or Flakes may refer to: People * Floyd H. Flake (born 1945), A.M.E. minister, university administrator, former U.S. representative * Jeff Flake (born 1962), American politician * Christian "Flake" Lorenz, German musician and member of ...

".Awruch, C.A. (2007). "The reproductive biology and movement patterns of the draughtboard shark, (''Cephaloscyllium laticeps''): implications for bycatch management". PhD thesis, University of Tasmania, Australia. It is regarded as a nuisance by

lobster Lobsters are a family (biology), family (Nephropidae, Synonym (taxonomy), synonym Homaridae) of marine crustaceans. They have long bodies with muscular tails and live in crevices or burrows on the sea floor. Three of their five pairs of legs ...

fishers due to its habit of entering traps to eat the contents. Every year, substantial numbers of Australian swellsharks are caught as

bycatch Bycatch (or by-catch), in the fishing industry, is a fish or other marine species that is caught unintentionally while fishing for specific species or sizes of wildlife. Bycatch is either the wrong species, the wrong sex, or is undersized or juve ...

in the southeast Australian shark gillnet fishery, and more in

s and on longlines. These animals are usually released, and likely suffer minimal mortality due to their resilience. Since this species at present faces little risk from fisheries, the

(IUCN) has listed it under

. Although

commercial fisheries Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often ...

reported drops in Australian swellshark catches from 1973 to 1976 and 1998 to 2001, these appeared to have resulted from changing fishing habits rather than actual population declines. Nevertheless, as a precaution the government of Tasmania has instituted a possession limit of two sharks per person or five sharks per boat per day.

References

External links

"''Cephaloscyllium laticeps'', Australian swellshark" at FishBase
{{Taxonbar, from=Q2719434

Australian swellshark The Australian swellshark (''Cephaloscyllium laticeps'') or draughtboard shark, is a species of catshark, and part of the family Scyliorhinidae, endemic to southern Australia. This bottom-dwelling species can be found on the continental s ...

Endemic fauna of Australia Marine fish of Southern Australia