The notchheaded marblefish (''Aplodactylus etheridgii'') is a species of marine ray finned fish, one of the marblefishes belonging to 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 ...

Aplodactylidae. It is found in the southwestern Pacific Ocean.

Taxonomy

The notchheaded marblefish was first formally described in 1889 as ''Haplodactylus etheridgii'' by the

Northern Ireland Northern Ireland ( ga, Tuaisceart Éireann ; sco, label= Ulster-Scots, Norlin Airlann) is a part of the United Kingdom, situated in the north-east of the island of Ireland, that is variously described as a country, province or region. Nort ...

born Australian herpetologist and

ichthyologist 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 Octobe ...

James Douglas Ogilby James Douglas Ogilby (16 February 1853 – 11 August 1925) was an Australian ichthyologist and herpetologist. Ogilby was born in Belfast, Ireland, and was the son of zoologist William Ogilby and his wife Adelaide, née Douglas. He received h ...

with the type locality given as the Admiralty Islets off

Lord Howe Island Lord Howe Island (; formerly Lord Howe's Island) is an irregularly crescent-shaped volcanic remnant in the Tasman Sea between Australia and New Zealand, part of the Australian state of New South Wales. It lies directly east of mainland P ...

. 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 ...

of this fish honours the British

geologist A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, althou ...

and

paleontologist Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...

Robert Etheridge Jr., the leader of the expedition on which the type was collected.

Description

The notchheaded marblefish has an elongate body which has a depth equivalent to roughly a quarter of its

standard length Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish m ...

. The largest individuals have a bony ridge above the eye, with the space between the eyes being concave. 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, mostly

multicuspid The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone to ...

teeth with a few tricuspid 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 (; lat, vomer, lit=ploughshare) 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 maxill ...

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

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 ...

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 profile of the head shows a notch to the rear of the eye. The dorsal fin contains 15-17 spines and 19-20 soft rays while 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 ...

has 3 spines and 6-7 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. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish ...

recorded is . This species has a brown body covered in very small white spots and it has large white patches along the flanks and an orange rear edge to the operculum. It has a grey belly while the fins are brown, apart from the outer parts of the lower pectoral fin rays which are yellowish.

Distribution and habitat

The notchheaded marbklefish is found only around islands in the

Tasman Sea The Tasman Sea (Māori: ''Te Tai-o-Rēhua'', ) is a marginal sea of the South Pacific Ocean, situated between Australia and New Zealand. It measures about across and about from north to south. The sea was named after the Dutch explorer Abe ...

in the southwestern Pacific Ocean. In Australian waters it is found off Lord Howe Island and Norfolk Island while in New Zealand it occurs at the Kermadec Islands and the northern coast of New Zealand's North Island. It is found on coastal reefs at depths between .

Biology

The notchheaded marblefish is a herbivorous species which grazes on algae.

References

* * * Tony Ayling & Geoffrey Cox, ''Collins Guide to the Sea Fishes of New Zealand'', (William Collins Publishers Ltd, Auckland, New Zealand 1982) {{Taxonbar, from=Q2316947 Aplodactylidae Endemic marine fish of New Zealand Fish described in 1889