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The draughtsboard shark (''Cephaloscyllium isabellum'') 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 ...
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 ...
, and 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, so named for its "
checkerboard A checkerboard (American English) or chequerboard (British English; see spelling differences) is a board of checkered pattern on which checkers (also known as English draughts) is played. Most commonly, it consists of 64 squares (8×8) of altern ...
" color pattern of dark blotches. It is
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 els ...
to
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 List of islands of New Zealand, smaller islands. It is the ...
, where it is also known as the carpet shark (which usually refers to the entire
order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...
Orectolobiformes Carpet sharks are sharks classified in the order Orectolobiformes . Sometimes the common name "carpet shark" (named so because many species resemble ornately patterned carpets) is used interchangeably with "wobbegong", which is the common name ...
). This shark typically reaches in length and has a thick body with a broad, flattened head and a capacious mouth. Its two dorsal fins are placed far back on the body, with the first much larger than the second. Occurring down to a depth of , the draughtsboard shark frequents 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 component, abiotic processes—deposition (geology), deposition of ...
s during the day and sandy flats at night. Its diet consists of fishes and
invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...
s. When threatened by a
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 ...
, it can take water or air into its body to inflate its body, which may be the cause of its unusual habit of
bark Bark may refer to: * Bark (botany), an outer layer of a woody plant such as a tree or stick * Bark (sound), a vocalization of some animals (which is commonly the dog) Places * Bark, Germany * Bark, Warmian-Masurian Voivodeship, Poland Arts, en ...
ing like a
dog The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the wolf. Also called the domestic dog, it is derived from the extinct Pleistocene wolf, and the modern wolf is the dog's nearest living relativ ...
. This species 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 ...
, with females laying smooth, tendril-bearing
egg capsule An egg case or egg capsule, often colloquially called a mermaid's purse, is the casing that surrounds the eggs of oviparous sharks, skates and chimaeras. Egg cases typically contain one embryo, except for big skate and mottled skate egg cases, ...
s in pairs. Draughtsboard sharks are often taken 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 juven ...
by
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 oft ...
, but are probably hardy enough to survive the experience. 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 ...
(IUCN) has listed this species 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

French naturalist
Pierre Joseph Bonnaterre Abbé Pierre Joseph Bonnaterre (1752, Aveyron – 20 September 1804, Saint-Geniez-d'Olt) was a French zoologist who contributed sections on cetaceans, mammals, birds, reptiles, amphibians, fish, and insects Insects (from Latin ') are ...
originally described the draughtsboard shark as ''Squalus isabella'', in the 1788
ichthyology Ichthyology is the branch of zoology devoted to the study of fish, including bony fish ( Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish ( Agnatha). According to FishBase, 33,400 species of fish had been described as of Octob ...
volume of the '' Tableau encyclopédique et méthodique des trois règnes de la nature''. He based his account on "L'Isabelle", referred to by Pierre-Marie-Auguste Broussonet in a 1780 ''Histoire de l'Académie Royale des Sciences'' paper. 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 ...
has since been lost. Later authors moved this species to the genus '' Cephaloscyllium''. The draughtsboard shark closely resembles the blotchy swellshark (''C. umbratile'') and the Australian swellshark (''C. laticeps''), both of which have been suspected to be the same species as ''C. isabellum'' by different authors at various times. The draughtsboard shark differs from the Australian swellshark in coloration and the form of its egg capsules (smooth in ''C. isabellum'' and ridged in ''C. laticeps''). It differs from the blotchy swellshark in coloration and morphometric measurements.


Distribution and habitat

The draughtsboard shark is found only in the coastal waters around New Zealand, including the Snares, the
Chatham Islands The Chatham Islands ( ) ( Moriori: ''Rēkohu'', 'Misty Sun'; mi, Wharekauri) are an archipelago in the Pacific Ocean about east of New Zealand's South Island. They are administered as part of New Zealand. The archipelago consists of about t ...
, and
Stewart Island Stewart Island ( mi, Rakiura, ' glowing skies', officially Stewart Island / Rakiura) is New Zealand's third-largest island, located south of the South Island, across the Foveaux Strait. It is a roughly triangular island with a total land ar ...
, where it is particularly common. It typically occurs at depths of on continental and insular shelves, though it has been recorded from as far down as . This shark is a bottom-dweller that favors 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 component, abiotic processes—deposition (geology), deposition of ...
s and adjacent areas of soft substrate. Adult males and females segregate from each other.


Description

Most draughtsboard sharks measure no more than long, though rarely an individual may reach ; a recorded maximum size of was probably based on 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'') or some other species. Females grow larger than males. This shark has a stocky, spindle-shaped body that tapers to a relatively thin
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 is short, broad, and somewhat flattened, with a broadly rounded 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 t ...
s have a triangular flap of skin in front, that do not reach the mouth. The oval eyes have rudimentary
nictitating eyelid 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 and are placed somewhat on top of the head; they have thick ridges above and below, and are followed by spiracles. The mouth is very large and curved, without furrows at the corners and with the upper teeth exposed when closed. 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 two
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 ...
s are placed far back on the body, with the first originating about over the middle 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 and the second originating 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 s ...
. The second dorsal fin is much smaller than the first, and also smaller than the anal fin. Males have short and thick claspers. 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 ...
is short and broad, with a barely developed lower lobe and a strong 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 Ma ...
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. The coloration of the draughtsboard shark gives it its
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 contra ...
: it is golden to brown above and light below, with up to 11 dark brown, irregular dorsal "saddles" that alternate with blotches on its flanks to form a
checkerboard A checkerboard (American English) or chequerboard (British English; see spelling differences) is a board of checkered pattern on which checkers (also known as English draughts) is played. Most commonly, it consists of 64 squares (8×8) of altern ...
pattern. Also distinctive is the saddle between its spiracles, which is stretched out and swept back on each side to form a bar over the gill slits.


Biology and ecology

During the day, the draughtsboard shark is lethargic and typically hides inside crevices or caves on the reef. At night, it emerges to forage for food over nearby sandy flats. This shark consumes a wide variety of fishes and invertebrates, including
spiny dogfish The spiny dogfish (''Squalus acanthias''), spurdog, mud shark, or piked dogfish is one of the best known species of the Squalidae (dogfish) family of sharks, which is part of the Squaliformes order. While these common names may apply to several ...
,
cod Cod is the common name for the demersal fish genus '' Gadus'', belonging to the family Gadidae. Cod is also used as part of the common name for a number of other fish species, and one species that belongs to genus ''Gadus'' is commonly not c ...
, sand perch, blennies,
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, cuttlefis ...
,
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 ...
, gastropods,
innkeeper worms ''Urechis caupo'' is a species of spoon worm in the family Urechidae, commonly known as the innkeeper echiuran, the fat innkeeper worm (because the tunnels often contain other animals), the innkeeper worm, or the penis fish. It is found in shal ...
,
krill Krill are small crustaceans of the order Euphausiacea, and are found in all the world's oceans. The name "krill" comes from the Norwegian word ', meaning "small fry of fish", which is also often attributed to species of fish. Krill are consid ...
,
hermit crab Hermit crabs are anomuran decapod crustaceans of the superfamily Paguroidea that have adapted to occupy empty scavenged mollusc shells to protect their fragile exoskeletons. There are over 800 species of hermit crab, most of which possess an a ...
s, crabs,
spiny lobster Spiny lobsters, also known as langustas, langouste, or rock lobsters, are a family (Palinuridae) of about 60 species of achelate crustaceans, in the Decapoda Reptantia. Spiny lobsters are also, especially in Australia, New Zealand, Ireland, S ...
s, and even sea squirts. Individuals have been observed sucking innkeeper worms out of their burrows, and swimming around with the antennae of large lobsters sticking out of their mouths for hours. A known
parasite Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted structurally to this way of lif ...
of this species is the
tapeworm Eucestoda, commonly referred to as tapeworms, is the larger of the two subclasses of flatworms in the class Cestoda (the other subclass is Cestodaria). Larvae have six posterior hooks on the scolex (head), in contrast to the ten-hooked Cestod ...
''Calyptrobothrium chalarosomum''. Like other ''Cephaloscyllium'' species, the draughtsboard shark has the ability to inflate its body dramatically in response to a
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 ...
; this defense mechanism may be behind reports of this species
bark Bark may refer to: * Bark (botany), an outer layer of a woody plant such as a tree or stick * Bark (sound), a vocalization of some animals (which is commonly the dog) Places * Bark, Germany * Bark, Warmian-Masurian Voivodeship, Poland Arts, en ...
ing like a large
dog The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the wolf. Also called the domestic dog, it is derived from the extinct Pleistocene wolf, and the modern wolf is the dog's nearest living relativ ...
. While it usually inflates with water, when captured by humans and brought to the surface it may inflate with air instead. When the shark deflates, the "bark" is produced by the pressurized air as it is released explosively through the
cardiac sphincter The esophagus (American English) or oesophagus (British English; both ), non-technically known also as the food pipe or gullet, is an organ in vertebrates through which food passes, aided by peristaltic contractions, from the pharynx to the ...
of the stomach. This species 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 ...
, with females laying two eggs at a time. The smooth, cream-colored egg cases measure long, and have long, spiral tendrils at the corners that allow them to be fastened to underwater objects. Newly hatched sharks measure long; males and females
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 and long respectively.


Human interactions

Common and harmless, draughtsboard sharks are often caught incidentally by
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 ...
,
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 ban ...
, and probably set net fisheries. It is likely that most captured sharks survive to be returned to the water alive, as this species can tolerate being out of water for an extended period of time. From 1988 to 1991, there was a New Zealand shark liver fishery and reported catches of draughtsboard sharks were 74–540 tons per year. After the fishery was discontinued, catches dropped to under five tons per year.


Conservation status

The New Zealand
Department of Conservation An environmental ministry is a national or subnational government agency politically responsible for the environment and/or natural resources. Various other names are commonly used to identify such agencies, such as Ministry of the Environment, ...
has classified the draughtsboard shark as "Not Threatened" under the
New Zealand Threat Classification System The New Zealand Threat Classification System is used by the Department of Conservation to assess conservation priorities of species in New Zealand. The system was developed because the IUCN Red List, a similar conservation status system, had some ...
. Because its population seems healthy and free from significant threats, 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 ...
(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. Th ...
.


References

{{Taxonbar, from=Q2639518 Cephaloscyllium Endemic marine fish of New Zealand Taxa named by Pierre Joseph Bonnaterre Fish described in 1788