''Aplodactylus arctidens'', the marblefish or southern seacarp, is a species of marine

ray finned fish Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of skin ...

, one of the marblefishes belonging to the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Aplodactylidae ''Aplodactylus'' is a genus of marine ray-finned fishes, commonly known as marblefishes or sea carps. It is the only genus in the monotypy, monogeneric Family (biology), family, Aplodactylidae. The fishes in this genus are found in the south east ...

. It is found in the southwestern Pacific Ocean.

Taxonomy

''Aplodactylus arctidens'' was first formally described in 1842 by the

Scottish Scottish usually refers to something of, from, or related to Scotland, including: *Scottish Gaelic, a Celtic Goidelic language of the Indo-European language family native to Scotland *Scottish English *Scottish national identity, the Scottish ide ...

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and

naturalist Natural history is a domain of inquiry involving organisms, including animals, fungi, and plants, in their natural environment, leaning more towards observational than experimental methods of study. A person who studies natural history is cal ...

Sir John Richardson with the type locality given as Port Arthur on

Tasmania Tasmania (; palawa kani: ''Lutruwita'') is an island States and territories of Australia, state of Australia. It is located to the south of the Mainland Australia, Australian mainland, and is separated from it by the Bass Strait. The sta ...

. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

''arctidens'' is a compound of ''arctatus'' meaning "drawn close together" and ''dens'' meaning "teeth", a reference to the densely packed rows of teeth in both jaws.

Description

''Aplodactylus arctidens'' has an elongate body which is one third to one fifth as deep as its

standard length Fish measurement is the measuring of individual fish and various parts of fish anatomy, their anatomies, for data used in many areas of ichthyology, including Taxonomy (biology), taxonomy and fishery biology. Overall length Standard length (SL) is ...

. It has a short snout and a rounded head which has a small mouth which is slightly downturned and has fleshy lips, the upper lip projecting. The jaws have small,

tricuspid The tricuspid valve, or right atrioventricular valve, is on the right dorsal side of the mammalian heart, at the superior portion of the right ventricle. The function of the valve is to allow blood to flow from the right atrium to the right vent ...

teeth with a few sharply pointed ones too and they are set on 3-4 rows in the jaws. The outermost row has the largest teeth and there are two patches of

vomerine teeth The vomer (; ) is one of the unpaired facial bones of the skull. It is located in the midsagittal line, and articulates with the sphenoid, the ethmoid, the left and right palatine bones, and the left and right maxillary bones. The vomer forms t ...

. There are two pairs of nostrils, the front pair have fleshy flap with small tentacles on the front and rear margins. There is a wide, flattened spine on the operculum which does not reach the margin. The

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

has a long base but it is nearly split in two by a deep and wide incision between the spiny and soft rayed parts. The dorsal fin contains 16-19 spines and 16-18 soft rays while the

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

has 3 spines and 6-8 soft rays. It has large pectoral fins which may be longer than the head and the lowest 5-6 rays are unbranched and fleshy. The body is covered in small, cycloid scales which are embedded in the skin, these extend on to the cheeks and operculum and create a sheath along base of the spiny portion of the dorsal fin. The largest

total length Fish measurement is the measuring of individual fish and various parts of their anatomies, for data used in many areas of ichthyology, including taxonomy and fishery biology. Overall length Standard length (SL) is the length of a fish measured f ...

recorded is . The overall colour of the head, body and fins is olive green or brown with a large number of small whitish irregular spots, blotches and lines.

Distribution and habitat

''Aplodactylus arctidens'' is found in the southwestern Pacific Ocean. It occurs in southern Australia from immediately east of

Mallacoota Mallacoota is a town in the East Gippsland region in the state of Victoria, Australia. At the 2021 census, Mallacoota had a population of 1,183. It is the last official township on Victoria's east coast before the border with New South Wales. ...

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east to

Kangaroo Island Kangaroo Island (, ) is Australia's third-largest island, after Tasmania and Melville Island, Northern Territory, Melville Island. It lies in the state of South Australia, southwest of Adelaide. Its closest point to the mainland is Snapper Poi ...

South Australia South Australia (commonly abbreviated as SA) is a States and territories of Australia, state in the southern central part of Australia. With a total land area of , it is the fourth-largest of Australia's states and territories by area, which in ...

and in southern

. It is found throughout New Zealand from the

Three Kings Islands 3 (three) is a number, numeral (linguistics), numeral and numerical digit, digit. It is the natural number following 2 and preceding 4, and is the smallest odd prime number and the only prime preceding a square number. It has religious and cul ...

in the north to the

Snares Islands The Snares Islands (; officially Snares Islands / Tini Heke), known colloquially as The Snares, is a group of uninhabited islands lying about south of New Zealand's South Island and to the south-southwest of Stewart Island / Rakiura. The Snar ...

south of New Zealand's

South Island The South Island ( , 'the waters of Pounamu, Greenstone') is the largest of the three major islands of New Zealand by surface area, the others being the smaller but more populous North Island and Stewart Island. It is bordered to the north by ...

, it is also found at the

Chatham Islands The Chatham Islands ( ; Moriori language, Moriori: , 'Misty Sun'; ) are an archipelago in the Pacific Ocean about east of New Zealand's South Island, administered as part of New Zealand, and consisting of about 10 islands within an approxima ...

. It is found on weedy reefs in shallow water at depths between .

Biology

''Aplodactylus arctidens'' is mainly

herbivorous A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat n ...

grazing on algae, mainly

red Red is the color at the long wavelength end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength of approximately 625–750 nanometres. It is a primary color in the RGB color model and a seconda ...

and

brown algae Brown algae (: alga) are a large group of multicellular algae comprising the class (biology), class Phaeophyceae. They include many seaweeds located in colder waters of the Northern Hemisphere. Brown algae are the major seaweeds of the temperate ...

, but it will eat any small animals it finds within the algae. It is a solitary species which defends a

territory A territory is an area of land, sea, or space, belonging or connected to a particular country, person, or animal. In international politics, a territory is usually a geographic area which has not been granted the powers of self-government, ...

, In New Zealand

spawning Spawn is the Egg cell, eggs and Spermatozoa, sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of freely releasing eggs and sperm into a body of water (fresh or marine); the physical act is ...

occurs in August and September.

Fisheries

''Aplodactylus arctidens'' is not pursued by fisheries, its flesh is not reputed to be very palatable.

References

* * * Tony Ayling & Geoffrey Cox, ''Collins Guide to the Sea Fishes of New Zealand'', (William Collins Publishers Ltd, Auckland, New Zealand 1982) {{Taxonbar, from=Q2397191 Aplodactylidae Fish described in 1839