''Hoplichthys'', the ghost flatheads, is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of marine

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or h ...

es native to the

Indian Indian or Indians may refer to: Peoples South Asia * Indian people, people of Indian nationality, or people who have an Indian ancestor ** Non-resident Indian, a citizen of India who has temporarily emigrated to another country * South Asia ...

and

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contin ...

s. This genus is the only member 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 ...

Hoplichthyidae.

Taxonomy

Hoplichthys was first proposed as a

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...

genus in 1829 by the 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 kingdom, including the structure, embryology, evolution, classification, habits, and d ...

Georges Cuvier when he described its

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specime ...

, and only species at that time, ''H. langsdorfi'' from Japan. In 1873 the German naturalist Johann Jakob Kaup considered that the genus ''Hoplichthys'' was so different from other "flathead" taxa that it merited placing in a

monogeneric In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

family, the Hoplichthyidae. The 5th edition of '' Fishes of the World'' classifies this family within the suborder

Platycephaloidei Platycephaloidei is a suborder of ray-finned fishes, part of the order Scorpaeniformes, and includes the flatheads, ghost flatheads and sea robins. Taxonomy Platycephaloidei was first recognised and named as a taxonomic grouping in 1943 by the ...

in the order

Scorpaeniformes The Scorpaeniformes are a diverse order of ray-finned fish, including the lionfishes and sculpins, but have also been called the Scleroparei. It is one of the five largest orders of bony fishes by number of species, with over 1,320. They are ...

. Other authorities differ and do not consider the Scorpaeniformes to be a valid order because the

Perciformes Perciformes (), also called the Percomorpha or Acanthopteri, is an order or superorder of ray-finned fish. If considered a single order, they are the most numerous order of vertebrates, containing about 41% of all bony fish. Perciformes means ...

is not monophyletic without the taxa within the Scorpaeniformes being included within it. These authorities consider the Platycephalidae to belong to the suborder

, along with the families Bembridae, Parabembridae, Platycephalidae and Plectrogeniidae within the Perciformes. However, some workers have put forward evidence that there may be a rather surprising sister group relationship between this family and the

gobies Gobiidae or gobies is a family of bony fish in the order Gobiiformes, one of the largest fish families comprising more than 2,000 species in more than 200 genera. Most of gobiid fish are relatively small, typically less than in length, and the ...

as they share more seemingly unique derived characters with each other than with other taxa, this needs to be further investigated,.

Etymology

''Hoplichthys'' combines ''hoplo'', meaning "armed", with ''ichthys'', which means fish. There is series of large bony plates on the body of ''H. langsdorfii'', each of which bears two spines and this is thpought what the first part of the genus name refers to. Cuvier spelled it as ''Oplichthys'' in hist text but it was ''Hoplichthys'' in the table of contents and this is the prevailing usage.

Species

There are currently 17 recognized species in this genus: * '' Hoplichthys acanthopleurus''

Regan The family name Regan, along with its cognates O'Regan, O Regan, Reagan, and O'Reagan, is an Anglicized form of the Irish surname Ó Riagáin or Ó Ríogáin, from Ua Riagáin. The meaning is likely to have originated in ancient Gaelic ''ri'' ...

, 1908 * '' Hoplichthys citrinus'' C. H. Gilbert, 1905 (Lemon ghost flathead) * '' Hoplichthys fasciatus'' Matsubara, 1937 * '' Hoplichthys filamentosus'' Matsubara & Ochiai, 1950 (Long-ray ghost flathead) * '' Hoplichthys gilberti'' D. S. Jordan & R. E. Richardson, 1908 * '' Hoplichthys gregoryi'' ( Fowler, 1938) * '' Hoplichthys haswelli''

McCulloch McCulloch is a Scottish surname. It's a variation of the Northern Irish surname McCullough. It's commonly found in Galloway. Notable people with the surname include: *Alan McCulloch (politician), New Zealand politician *Alan McLeod McCulloch ( ...

, 1907 (Armoured flathead) * '' Hoplichthys imamurai''

Nagano Nagano may refer to: Places * Nagano Prefecture, a prefecture in Japan ** Nagano (city), the capital city of the same prefecture *** Nagano 1998, the 1998 Winter Olympics *** Nagano Olympic Stadium, a baseball stadium in Nagano *** Nagano Universi ...

, McGrouther & Yabe, 2013 (Imamura's ghost flathead) Nagano, Y., McGrouther, M.A. & Yabe, M. (2013): A new species of the hoplichthyid genus ''Hoplichthys'' (Teleostei: Hoplichthyidae) from northern Western Australia. ''Zootaxa, 3681 (3): 241–248.'' * '' Hoplichthys langsdorfii'' Cuvier, 1829 * '' Hoplichthys mcgroutheri'' Nagano, Imamura & Yabe, 2014 (McGrouther's ghost flathead) Nagano, Y., Imamura, H. & Yabe, M. (2014): A new ghost flathead (Scorpaeniformes: Hoplichthyidae) from southwestern Australia. ''Ichthyological Research, 62 (3): 245-252.'' * '' Hoplichthys mimaseanus'' Nagano, Endo & Yabe, 2013 Nagano, Y., Endo, H. & Yabe, M. (2013): ''Hoplichthys mimaseanus'', a New Ghost Flathead from East Asia and Western Australia (Teleostei: Hoplichthyidae). ''Bulletin of the National Museum of Natural Science, Ser. A., Supplement No. 7: 1–9.'' * '' Hoplichthys ogilbyi'' McCulloch, 1914 (Ogilby's ghost flathead) * '' Hoplichthys pectoralis'' (Fowler, 1943) * '' Hoplichthys platophrys'' C. H. Gilbert, 1905 * '' Hoplichthys prosemion'' (Fowler, 1938) * '' Hoplichthys regani'' D. S. Jordan, 1908 (Ghost flathead) * '' Hoplichthys smithi'' (Fowler, 1938)

Characteristics

''Hoplichthys'' ghost flatheads have a very wide, flattened head, an elongate body which has no scales but does have many spines and ridges on the upper body, There is a row of large spined bony plates, called scutes, running along the middle of the flanks. The lowermost 3 to 5 fin rays of 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 ...

are separated from the membrane. There are no spines in the anal fin and they have 26 vertebrae. They have large mouths with tiny villiform teeth in the jaws, on the

vomer 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 max ...

, on the

palatine A palatine or palatinus (in Latin; plural ''palatini''; cf. derivative spellings below) is a high-level official attached to imperial or royal courts in Europe since Roman times.

and in the pharynegeals. There are two separate

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, the first is short-based and contains 6 or 7 spines and the second is long-based and contains between 13 and 16 soft rays. The anal fin has a single spine and between 15 and 17 soft rays and is around the same length as the second dorsal fin. 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 ...

can be rounded or it can be

emarginate The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular o ...

. The pelvic fins are located on the thoraxand have a single spine and 5 soft rays. The majority of the species are yellow, pinkish, or brown in colour on the upper body and flanks, with various spots and mottles, and they are pink, white or silver ventrally. The pectoral fins vary in colour from yellowish brown to hyaline marked with crossbarring, spotting or mottling. The first dorsal fin is frequently dark towards its rear, or has wavy line across it. The caudal fin is typically hyaline, although in some species it has a dark distal margin or spots at the base. The maximum length attained by these fishes varies from a standard length of in ''H. fasciatus'' to in ''H. haswelli''.

Distribution, habitat and biology

''Hoplichthys'' ghost flatheads have an Indo-Pacific distribution, occurring from the eastern coast of Africa to Hawaii. they are benthic fishes living on the bottom in continental shelf and

slope In mathematics, the slope or gradient of a line is a number that describes both the ''direction'' and the ''steepness'' of the line. Slope is often denoted by the letter ''m''; there is no clear answer to the question why the letter ''m'' is use ...

waters at depths between . The larvae and juveniles are found in shallower water than the adults. These fishes prey on a variety of crustaceans and other fishes.

References

{{Taxonbar, from=Q2729700 Platycephaloidei Hoplichthyidae Taxa named by Georges Cuvier