Pseudorhabdosynochus
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''Pseudorhabdosynochus'' is a
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
monopisthocotylea The Monopisthocotylea are a subclass of parasitic flatworms in the class Monogenea. WoRMS (2019). Monopisthocotylea. Accessed at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=119219 on 2019-02-08 Yamaguti, S. (1963). Systema Helminthum V ...
n
monogenea Monogeneans are a group of ectoparasitic flatworms commonly found on the skin, gills, or fins of fish. They have a direct lifecycle and do not require an intermediate host. Adults are hermaphrodites, meaning they have both male and female reprod ...
ns, included in the family
Diplectanidae The Diplectanidae are a family of monopisthocotylean monogeneans. They are all parasitic on the gills of fish (marine or freshwater). Diplectanids are small animals, generally around 1 mm in length. As parasites, they can be extremely numerou ...
. The type-species of the genus is ''Pseudorhabdosynochus epinepheli'' ( Yamaguti, 1938).
The genus includes more than 80
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 ...
, which are all parasitic on the
gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...
s of marine fish, especially
grouper Groupers are fish of any of a number of genera in the subfamily Epinephelinae of the family Serranidae, in the order Perciformes. Not all serranids are called "groupers"; the family also includes the sea basses. The common name "grouper" is u ...
s. Since groupers are mostly abundant in warm waters, species of ''Pseudorhabdosynochus'' are found in warm parts of the oceans, especially in
coral reef A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in groups. Co ...
s, but species have also been found in deep-sea groupers. Several species of ''Pseudorhabdosynochus'' are
pathogen In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...
s of maricultured groupers.


Morphology

All species of ''Pseudorhabdosynochus'' are small animals, ranging 0.3–1 mm in length. As most monogeneans, they are flat, with an anterior head bearing four oculi and head
glands In animals, a gland is a group of cells in an animal's body that synthesizes substances (such as hormones) for release into the bloodstream (endocrine gland) or into cavities inside the body or its outer surface (exocrine gland). Structure De ...
, a main elongate body and a posterior
haptor The haptor is the attachment organ of the monogeneans, a group of parasitic Platyhelminthes. The haptor is sometimes called opisthaptor (from ''opistho-'': behind) to emphasize that it is located in the posterior part of the body, and to differe ...
. The digestive system includes an anterior muscular
pharynx The pharynx (plural: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the oesophagus and trachea (the tubes going down to the stomach and the lungs). It is found in vertebrates and invertebrates, though its struc ...
, and two lateral intestinal branches (or caeca); as in all
Platyhelminthes The flatworms, flat worms, Platyhelminthes, or platyhelminths (from the Greek language, Greek πλατύ, ''platy'', meaning "flat" and ἕλμινς (root: ἑλμινθ-), ''helminth-'', meaning "worm") are a Phylum (biology), phylum of relati ...
, there is no anus. The
haptor The haptor is the attachment organ of the monogeneans, a group of parasitic Platyhelminthes. The haptor is sometimes called opisthaptor (from ''opistho-'': behind) to emphasize that it is located in the posterior part of the body, and to differe ...
, in the posterior part of the body, is a specialized organ used to attach to the
host A host is a person responsible for guests at an event or for providing hospitality during it. Host may also refer to: Places * Host, Pennsylvania, a village in Berks County People *Jim Host (born 1937), American businessman * Michel Host ...
. The haptor includes sclerotized elements, namely a ventral bar, two lateral (dorsal) bars, two ventral hooks and two dorsal hooks, and fourteen hooklets. As in most diplectanids, the haptor bears special, characteristic, structures called
squamodisc Squamodiscs are epidermal structures, which are typical of and found only in certain monogeneans of the family Diplectanidae. There are, typically, two squamodiscs, one ventral and one dorsal, located on the haptor of the monogenean. Squamodisc ...
s. The squamodiscs (one ventral and one dorsal) of species of ''Pseudorhabdosynochus'' are made up of numerous rodlets aligned as concentric rows. All species of the genus have two squamodiscs except '' Pseudorhabdosynochus sinediscus'' Neifar & Euzet, 2007 in which these organs are completely lacking. Adults are
hermaphroditic In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many taxonomic groups of animals (mostly invertebrates) do not have separ ...
. The reproductive organ include a single
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 a single
testis A testicle or testis (plural testes) is the male reproductive gland or gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testostero ...
. As in all diplectanids, the
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. ...
(or germarium) is anterior to the
testis A testicle or testis (plural testes) is the male reproductive gland or gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testostero ...
and loops around the right intestinal caecum. Species of ''Pseudorhabdosynochus'' are characterized by a sclerotized male copulatory organ, or "quadriloculate organ", which has the shape of a bean with four internal chambers. The
vagina In mammals, the vagina is the elastic, muscular part of the female genital tract. In humans, it extends from the vestibule to the cervix. The outer vaginal opening is normally partly covered by a thin layer of mucosal tissue called the hymen ...
includes a sclerotized part, which is a complex structure with several chambers and canals, generally used for the diagnosis and differentiation of species.


Etymology and nomenclatural case

The origin of the name ''Pseudorhabdosynochus'' merits an explanation. ‘
Pseudo- The prefix pseudo- (from Greek ψευδής, ''pseudes'', "false") is used to mark something that superficially appears to be (or behaves like) one thing, but is something else. Subject to context, ''pseudo'' may connote coincidence, imitation, ...
’ (from Greek ψευδής, pseudes, "lying, false") is a
prefix A prefix is an affix which is placed before the Word stem, stem of a word. Adding it to the beginning of one word changes it into another word. For example, when the prefix ''un-'' is added to the word ''happy'', it creates the word ''unhappy'' ...
commonly used in creating a new
scientific name 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 ...
for a taxon that superficially appears to be a taxon, but actually is another. The famous Japanese parasitologist
Satyu Yamaguti was a Japanese parasitologist, entomologist, and helminthologist. He was a specialist of mosquitoes and helminths such as digeneans, monogeneans, cestodes, acanthocephalans and nematodes. He also worked on the parasitic crustaceans Copepoda and ...
described a ‘membranous plaque’ on the posterior region of ''
Pseudorhabdosynochus epinepheli ''Pseudorhabdosynochus epinepheli'' is a diplectanid monogenean parasitic on the gills of species of groupers. It is the type species of the genus '' Pseudorhabdosynochus'' Yamaguti, 1958. Description ''Pseudorhabdosynochus epinepheli'' is a ...
'' and created the generic name ''Pseudorhabdosynochus'' in reference to the diplectanid genus ''
Rhabdosynochus Rhabdosynochus is a genus of monopisthocotylean monogeneans, belonging to the family Diplectanidae.Mizelle, J. D., & Blatz, V. (1941). Studies on monogenetic trematodes. VI. Two new dactylogyrid genera from Florida fishes. The American Midland N ...
'' which, in his interpretation, also had lateral plaques. It has been shown later that ‘plaques’ in '' P. epinepheli'' was an erroneous interpretation of damaged specimens. Moreover, the diagnosis of ''
Rhabdosynochus Rhabdosynochus is a genus of monopisthocotylean monogeneans, belonging to the family Diplectanidae.Mizelle, J. D., & Blatz, V. (1941). Studies on monogenetic trematodes. VI. Two new dactylogyrid genera from Florida fishes. The American Midland N ...
'' was later modified and it is now considered that species of this genus do not have plaques. Therefore, the genus name ''Pseudorhabdosynochus'' is the result of both an erroneous observation and an erroneous comparison by
Satyu Yamaguti was a Japanese parasitologist, entomologist, and helminthologist. He was a specialist of mosquitoes and helminths such as digeneans, monogeneans, cestodes, acanthocephalans and nematodes. He also worked on the parasitic crustaceans Copepoda and ...
. However, it is valid according to the ICZN. ''Pseudorhabdosynochus'' is also an interesting nomenclatural case. Yamaguti described the same species twice, the first time in 1938 (as ''Diplectanum epinepheli'' Yamaguti, 1938) and the second time in 1958 Yamaguti, S. 1958: Studies on the helminth fauna of Japan. Part 53. Trematodes of fishes, XII. ''Publications of the Seto Marine Biological Laboratory'', 7, 53-88
ArticlePDF
(as ''Pseudorhabdosynochus epinepheli'' Yamaguti, 1958). In both papers, the species was described from parasites collected from the same fish species, the grouper '' Epinephelus akaara'' off
Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...
. Kritsky & Beverley-Burton (1986) solved this case with reference to the
International Code of Zoological Nomenclature The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its publisher, the ...
. The type-species of the genus is the name ''Pseudorhabdosynochus epinepheli'' Yamaguti, 1958. ''Pseudorhabdosynochus epinepheli'' Yamaguti, 1958 is a junior synonym of ''Pseudorhabdosynochus epinepheli'' (Yamaguti, 1938) Kritsky & Beverley-Burton, 1986 and ''
Pseudorhabdosynochus epinepheli ''Pseudorhabdosynochus epinepheli'' is a diplectanid monogenean parasitic on the gills of species of groupers. It is the type species of the genus '' Pseudorhabdosynochus'' Yamaguti, 1958. Description ''Pseudorhabdosynochus epinepheli'' is a ...
'' (Yamaguti, 1938) Kritsky & Beverley-Burton, 1986 is the modern valid combination for ''Diplectanum epinepheli'' Yamaguti, 1938. The latter species (a taxon) and the type-species of the
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
(a name) are considered to correspond to the same biological taxon but have different, although valid, names. Recent re-examination of type-specimens have confirmed this interpretation.


Hosts

Species of ''Pseudorhabdosynochus'' are parasitic exclusively on the
gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...
filaments of marine fish. Most of these fish belong to the family
Serranidae The Serranidae are a large family of fishes belonging to the order Perciformes. The family contains about 450 species in 65 genera, including the sea basses and the groupers (subfamily Epinephelinae). Although many species are small, in some case ...
and are commonly known as
grouper Groupers are fish of any of a number of genera in the subfamily Epinephelinae of the family Serranidae, in the order Perciformes. Not all serranids are called "groupers"; the family also includes the sea basses. The common name "grouper" is u ...
s, such as many species of the genus ''
Epinephelus ''Epinephelus'' is a genus of marine ray-finned fish, groupers from the subfamily Epinephelinae, part of the family Serranidae, which also includes the anthias and sea basses. They are predatory fish, largely associated with reefs and are found i ...
'', and also species of ''
Cephalopholis ''Cephalopholis'' is a genus of marine ray-finned fish, groupers from the subfamily Epinephelinae in the family Serranidae, which also includes the anthias and sea basses. Many of the species have the word "hind" as part of their common name in ...
'', ''
Mycteroperca ''Mycteroperca'' is a genus of marine ray-finned fish, groupers from the subfamily Epinephelinae, part of the family Serranidae, which also includes the anthias and sea basses. They are predatory fish, largely associated with reefs and are found ...
'' and ''
Variola Smallpox was an infectious disease caused by variola virus (often called smallpox virus) which belongs to the genus Orthopoxvirus. The last naturally occurring case was diagnosed in October 1977, and the World Health Organization (WHO) cer ...
''. A few species have also been described from fish of the genera ''
Alphestes ''Alphestes'' is a genus of marine ray-finned fish, groupers from the subfamily Epinephelinae in the family Serranidae The Serranidae are a large family of fishes belonging to the order Perciformes. The family contains about 450 species in 65 ...
'', ''
Paranthias ''Paranthias'' is a genus of marine ray-finned fish, groupers from the subfamily Epinephelinae, part of the family Serranidae, which also includes the anthias and sea basses. They are found in the Atlantic Ocean and the eastern Pacific Ocean. ...
'' and ''
Paralabrax ''Paralabrax'' is a genus of fishes in the family Serranidae. They are known commonly as rock basses.Pondella, D. J., et al. (2003)The phylogeny of ''Paralabrax'' (Perciformes: Serranidae) and allied taxa inferred from partial 16S and 12S mitocho ...
''. As most diplectanids, species of ''Pseudorhabdosynochus'' are generally strictly species-specific, i.e. a species is found on a single species of
host A host is a person responsible for guests at an event or for providing hospitality during it. Host may also refer to: Places * Host, Pennsylvania, a village in Berks County People *Jim Host (born 1937), American businessman * Michel Host ...
and no others. However, several exceptions have been reported. Some species of groupers harbour a wide biodiversity of ''Pseudorhabdosynochus'' species (and sometimes other monogeneans as well). Examples are '' Epinephelus maculatus'' which has 8 distinct ''Pseudorhabdosynochus'' species, and '' Epinephelus malabaricus'' which has 7 species.


Life cycle

The
life cycle Life cycle, life-cycle, or lifecycle may refer to: Science and academia *Biological life cycle, the sequence of life stages that an organism undergoes from birth to reproduction ending with the production of the offspring * Life-cycle hypothesis ...
of ''Pseudorhabdosynochus'' species is similar to that of other diplectanid monogeneans. It is
monoxenous Monoxenous development, or monoxeny, characterizes a parasite whose development is restricted to a single host species. The etymology of the terms monoxeny / monoxenous derives from the two ancient Greek words (), meaning "unique", and (), m ...
, i.e. there is a single
host A host is a person responsible for guests at an event or for providing hospitality during it. Host may also refer to: Places * Host, Pennsylvania, a village in Berks County People *Jim Host (born 1937), American businessman * Michel Host ...
, the fish. The life-cycle includes a parasitic phase, the adult worm, and two stages which are free in the environment, the
egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the a ...
and the
larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...
. The adult
hermaphroditic In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many taxonomic groups of animals (mostly invertebrates) do not have separ ...
worm, which lives on the gills of fish, lays eggs in the water. The egg has an operculum. A larva develops in the egg and hatches through the operculum; the swimming larva is
ciliated The cilium, plural cilia (), is a membrane-bound organelle found on most types of eukaryotic cell, and certain microorganisms known as ciliates. Cilia are absent in bacteria and archaea. The cilium has the shape of a slender threadlike project ...
and called an
oncomiracidium An oncomiracidium is the ciliated and free-living larva of a monogenean, a type of parasitic flatworm commonly found on fish. It is similar to the miracidium of Trematoda, but has sclerotised Sclerotin is a component of the cuticle of various A ...
. The larva finds its host by swimming to it, first attaches to the skin and migrates to the gills, and eventually transforms itself into a young monogenean which is attached to the gill filament by its
haptor The haptor is the attachment organ of the monogeneans, a group of parasitic Platyhelminthes. The haptor is sometimes called opisthaptor (from ''opistho-'': behind) to emphasize that it is located in the posterior part of the body, and to differe ...
. During transformation from larva to adult, the monogenean loses its
cilia The cilium, plural cilia (), is a membrane-bound organelle found on most types of eukaryotic cell, and certain microorganisms known as ciliates. Cilia are absent in bacteria and archaea. The cilium has the shape of a slender threadlike projecti ...
and produces a new tegument, a phenomenon which is considered a general characteristic of the parasitic
Platyhelminthes The flatworms, flat worms, Platyhelminthes, or platyhelminths (from the Greek language, Greek πλατύ, ''platy'', meaning "flat" and ἕλμινς (root: ἑλμινθ-), ''helminth-'', meaning "worm") are a Phylum (biology), phylum of relati ...
or
Neodermata Neodermata is a clade of rhabditophoran flatworms containing the parasitic groups Trematoda, Monogenea and Cestoda. Description All neodermatans are parasites, in many groups having a free-swimming larval stage. The most striking feature unit ...
. Information is available for the life-cycle of '' Pseudorhabdosynochus lantauensis'', a parasite of the orange-spotted grouper ''
Epinephelus coioides The orange-spotted grouper (''Epinephelus coioides''), also known as the brown-spotted rockcod, estuary cod, estuary rockcod, goldspotted rockcod, greasy cod, North-west groper, orange spotted cod or blue-and-yellow grouper, is a species of marin ...
'', at a temperature of 30 °C. The adult lays 10-22 eggs/day. The eggs hatch within 2–4 days. The oncomiracidium is viable for 4-8 h and should find a host within this delay. After attachment, the oncomiracidium transforms into an adult in 4–7 days. The parasite produces eggs after 7 days. The life-cycle is thus complete in 13–20 days (at 30 °C). Certain species of ''Pseudorhabdosynochus'' parasitize groupers which show
spawning Spawn is the eggs and sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of releasing the eggs and sperm, and the act of both sexes is called spawning. Most aquatic animals, except for aquat ...
aggregations, i.e. the adult fish gather annually at a precise location and meet other fish of their own species only once per year. It has been suggested that transmission of ''Pseudorhabdosynochus'' species occurs preferentially during these spawning aggregations, from older infected fish to younger, uninfected, fish.


Pathology and control in mariculture

Species of ''Pseudorhabdosynochus'' are attached to the gills of groupers. No information is available on the pathogen effect of these parasites in wild groupers. Since the life-cycle is
monoxenous Monoxenous development, or monoxeny, characterizes a parasite whose development is restricted to a single host species. The etymology of the terms monoxeny / monoxenous derives from the two ancient Greek words (), meaning "unique", and (), m ...
and thus can be completed with a high rate of success in mariculture condition, species of ''Pseudorhabdosynochus'' can proliferate on
gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...
s of cultured groupers and become dangerous for the fish, inducing mortality.
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 ...
infections are often measured by two variables,
prevalence In epidemiology, prevalence is the proportion of a particular population found to be affected by a medical condition (typically a disease or a risk factor such as smoking or seatbelt use) at a specific time. It is derived by comparing the number o ...
(the proportion of infected
hosts A host is a person responsible for guests at an event or for providing hospitality during it. Host may also refer to: Places *Host, Pennsylvania, a village in Berks County People *Jim Host (born 1937), American businessman *Michel Host ( ...
) and intensity (the number of parasites per host). Prevalences as high as 100% (i.e. all fish are infected) have been reported for ''Pseudorhabdosynochus'' sp. in cage-cultured '' Epinephelus malabaricus'' in
Thailand Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is bo ...
,Ruangpan, L. & Tubkaew, R. (1993). Parasites of the cage cultured grouper ''Epinephelus malabaricus'' in Thailand. Paper presented at the Proceedings of Grouper Culture, Kaoseng, Songkhla, Thailand. for ''Pseudorhabdosynochus'' sp. on '' Epinephelus fuscoguttatus'' and ''
Epinephelus coioides The orange-spotted grouper (''Epinephelus coioides''), also known as the brown-spotted rockcod, estuary cod, estuary rockcod, goldspotted rockcod, greasy cod, North-west groper, orange spotted cod or blue-and-yellow grouper, is a species of marin ...
'' maricultured in
Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...
, and for '' P. beverleyburtonae'' on ''
Epinephelus marginatus ''Epinephelus marginatus'' (), the dusky grouper, yellowbelly rock cod or yellowbelly grouper, is a species of marine ray-finned fish, a grouper from the subfamily Epinephelinae which is part of the family Serranidae, which also includes the ant ...
'', wild or maricultured, in
Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
. Intensities are as high as up to 1,006 individual ''Pseudorhabdosynochus'' sp. per fish ('' Epinephelus fuscoguttatus'') in
Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...
, up to 294 '' P. coioidesis'' per fish (''
Epinephelus coioides The orange-spotted grouper (''Epinephelus coioides''), also known as the brown-spotted rockcod, estuary cod, estuary rockcod, goldspotted rockcod, greasy cod, North-west groper, orange spotted cod or blue-and-yellow grouper, is a species of marin ...
'') in South
China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
, 327 '' P. yucatanensis'' per fish on ''
Epinephelus morio The red grouper (''Epinephelus morio'') is a species of marine ray-finned fish, a grouper from the subfamily Epinephelinae which is part of the family Serranidae, which also includes the anthias and sea basses. It is found in the western Atlanti ...
'' in Mexico, and 500 '' P. epinepheli'' per 100 grams of gill filaments of '' Epinephelus akaara'' in
Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...
. Eradication of gill parasitic monogeneans is a problem because various chemical treatments can be harmful for the fish. Treatments used against ''Pseudorhabdosynochus'' species include freshwater, diluted
formalin Formaldehyde ( , ) ( systematic name methanal) is a naturally occurring organic compound with the formula and structure . The pure compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde (refer to section F ...
, and diluted
hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3% ...
(H2O2). Diluted
hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3% ...
(H2O2) seems the preferred treatment for '' P. epinepheli'' on '' Epinephelus akaara'' and '' P. lantauensis'' on ''
Epinephelus coioides The orange-spotted grouper (''Epinephelus coioides''), also known as the brown-spotted rockcod, estuary cod, estuary rockcod, goldspotted rockcod, greasy cod, North-west groper, orange spotted cod or blue-and-yellow grouper, is a species of marin ...
''.


List of species

Lists of species have been provided by Kritsky & Beverley-Burton (1986) and Justine (2007). The list below (about 80 species) is based on the World Register of Marine OrganismsWorld Register of Marine Organisms
/ref> with additions.


References


External links

* {{Taxonbar, from=Q18580720 Diplectanidae Monogenea genera Taxa named by Satyu Yamaguti