''Pseudorhabdosynochus regius'' is a diplectanid monogenean parasitic on the

gill A gill () is a respiration organ, respiratory organ that many aquatic ecosystem, 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 r ...

s of the mottled grouper (''Mycteroperca rubra'').

Etymology

The

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

, ''regius'', is from the

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

adjective meaning "royal". It was given in reference to the French name of the type-host, .

Description

''Pseudorhabdosynochus regius'' is a small monogenean, about 600-1300 μm in length. The species has the general characteristics of other species of ''

Pseudorhabdosynochus ''Pseudorhabdosynochus'' is a genus of monopisthocotylean monogeneans, included in the family Diplectanidae. The type-species of the genus is ''Pseudorhabdosynochus epinepheli'' ( Yamaguti, 1938). The genus includes more than 80 species, which a ...

'', with a flat 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 diffe ...

, which is the organ by which the monogenean attaches itself to the gill of is host. The haptor bears two

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. Squamodiscs ...

s, one ventral and one dorsal, which are small, with a length of 20-40 μm, and made up of only 10-11 rows of rodlets. The sclerotized male copulatory organ, or "quadriloculate organ", has the shape of a bean with four internal chambers, as in other species of ''

''.Kritsky, D. C. & Beverley-Burton, M. 1986: The status of ''Pseudorhabdosynochus'' Yamaguti, 1958, and ''Cycloplectanum'' Oliver, 1968 (Monogenea: Diplectanidae). ''Proceedings of the Biological Society of Washington'', 99, 17-20
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The

vagina In mammals and other animals, the vagina (: vaginas or vaginae) is the elastic, muscular sex organ, reproductive organ of the female genital tract. In humans, it extends from the vulval vestibule to the cervix (neck of the uterus). The #Vag ...

includes a sclerotized part, which is a complex structure, 26-35 μm in length. It exhibits a trumpet in continuity with the primary canal, a straight primary canal, and primary and secondary chambers included in a common sclerotised mass along the primary canal. The sclerotised vagina is the structure used by systematicians to differentiate species of ''

''. The closest relatives of ''P. regius'', based on the structure of its sclerotised vagina, are species mostly found in the Mediterranean Sea and parasites on species of ''

Mycteroperca ''Mycteroperca'' is a genus of marine ray-finned fish, groupers from the subfamily Epinephelinae, part of the Family (biology), family Serranidae, which also includes the Anthiinae, anthias and sea basses. They are predatory fish, largely associa ...

''.

Hosts and localities

The type-host of ''Pseudorhabdosynochus regius'' is the grouper mottled grouper (''Mycteroperca rubra'') and the species has not been found in another

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 * Host Island, in the Wilhelm Archipelago, Antarctica People * ...

. The type-locality if off

Dakar Dakar ( ; ; ) is the capital city, capital and List of cities in Senegal, largest city of Senegal. The Departments of Senegal, department of Dakar has a population of 1,278,469, and the population of the Dakar metropolitan area was at 4.0 mill ...

Senegal Senegal, officially the Republic of Senegal, is the westernmost country in West Africa, situated on the Atlantic Ocean coastline. It borders Mauritania to Mauritania–Senegal border, the north, Mali to Mali–Senegal border, the east, Guinea t ...

. The monogenean has also been found on fish of the same species caught off

Sfax Sfax ( ; , ) is a major port city in Tunisia, located southeast of Tunis. The city, founded in AD849 on the ruins of Taparura, is the capital of the Sfax Governorate (about 955,421 inhabitants in 2014), and a Mediterranean port. Sfax has a ...

Tunisia Tunisia, officially the Republic of Tunisia, is a country in the Maghreb region of North Africa. It is bordered by Algeria to the west and southwest, Libya to the southeast, and the Mediterranean Sea to the north and east. Tunisia also shares m ...

and off

Tripoli, Libya Tripoli, historically known as Tripoli-of-the-West, is the capital city, capital and largest city of Libya, with a population of about 1.317 million people in 2021. It is located in the northwest of Libya on the edge of the desert, on a point ...

. Thus, ''P. regius'' is known from the

Mediterranean Sea The Mediterranean Sea ( ) is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean basin and almost completely enclosed by land: on the east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern Eur ...

and the Eastern

Atlantic The Atlantic Ocean is the second largest of the world's five oceanic divisions, with an area of about . It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for se ...

. Only 14 species of diplectanids parasitic on

groupers Groupers are a diverse group of marine ray-finned fish in the family Epinephelidae, in the order Perciformes. Groupers were long considered a subfamily of the seabasses in Serranidae, but are now treated as distinct. Not all members of this f ...

are known in the

and ''P. regius'' is one of them.

Gallery

Pseudorhabdosynochus regius - with English captions.png, ''Pseudorhabdosynochus regius'' - with captions for parts and organs Parasite140133-fig3 Pseudorhabdosynochus regius (Diplectanidae) Sclerotised vaginae.png, Sclerotised

e of various specimens Parasite140133-fig2 Pseudorhabdosynochus regius (Diplectanidae) Haptor hard parts 2C-2G.png, Hard parts of the

Parasite140133-fig2 Pseudorhabdosynochus regius (Diplectanidae) Squamodisc 2H.png, Ventral

References

{{Taxonbar, from=Q19595152 Diplectanidae Animals described in 2015 Fauna of Senegal Fauna of Tunisia Fauna of Libya