|Lethacotyle fijiensis Manter & Prince, 1953|
Protomicrocotylidae is a family of monogenean parasites in the order Mazocraeidea.
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 reproductive structures. Monogeneans have a series of hooks which are used to attach onto fish, and as a result, could lead to infections.
Mazocraeidea is an order in the subclass Polyopisthocotylea within class Monogenea.
The type-genus of the family is Protomicrocotyle . The genus was created in 1922 by Thomas Harvey Johnston and Oscar Werner Tiegsfor a worm previously described under the name Acanthodiscus mirabile by MacCallum in 1918. The worm was parasitic on a crevalle jack of the New York Aquarium. Johnston & Tiegs originally proposed to create the subfamily Protomicrocotylinae, which was later raised to family level.
Thomas Harvey Johnston was an Australian biologist and parasitologist. He championed the efforts to eradicate the invasive prickly pear.
Oscar Werner Tiegs FRS FAA was an Australian zoologist whose career spanned the first half of the 20th century.
The New York Aquarium is the oldest continually operating aquarium in the United States, having opened in Castle Garden in Battery Park, Manhattan in 1896. Since 1957, it has been located on the boardwalk in Coney Island, Brooklyn. The aquarium is operated by the Wildlife Conservation Society (WCS) as part of its integrated system of four zoos and one aquarium, most notably the Bronx Zoo. It is accredited by the Association of Zoos and Aquariums (AZA).
Members of this family are elongate, flat, and long of 1 to several millimetres.The reproductive system includes many testes, located in the anterior region of the body between the ceca, and a single posterior ovary. The male copulatory organ usually has spines. The posterior attachment organ or haptor, which attaches the worm to the host, is asymmetrical and has three pairs of small hooks.
The cecum or caecum is an intraperitoneal pouch that is considered to be the beginning of the large intestine. It is typically located on the right side of the body.
The ovary is an organ found 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 the left and right sides of the body. The ovaries also secrete hormones that play a role in the menstrual cycle and fertility. The ovary progresses through many stages beginning in the prenatal period through menopause. It is also an endocrine gland because of the various hormones that it secretes.
The haptor is the attachment organ of the monogeneans, a group of parasitic Platyhelminthes. The haptor is sometimes called opisthaptor to emphasize that it is located in the posterior part of the body, and to differentiate it from the prohaptor, a structure including glands located at the anterior part of the body. According to Yamaguti (1963), the chief adhesive organ of the monogeneans, the haptor, is posterior, more or less discoid, muscular, may be divided into alveoli or loculi, is usually provided with anchors, has nearly always marginal larval hooklets, or is in a reduced form with anchors. The haptor may consist of symmetrical or asymmetrical, sessile or pedunculate, muscular suckers or clamps with or without supporting sclerites; accessory adhesive organs may be present in form of armed plaques, lappets or appendices.
As most other polyopisthocotyleans, members of the family Protomicrocotylidae have posterior clamps on their haptor. These clamps are of the gastrocotylid type, i.e. they include two accessory sclerites in addition to the other sclerites, but in some genera the clamps are simplified as microcotylid type, i.e. they have only five sclerites, and are even absent in members of the genus Lethacotyle .
Polyopisthocotylea is a subclass of parasitic flatworms in the class Monogenea.
Clamps are the main attachment structure of the Polyopisthocotylean monogeneans.
These ectoparasitic worms have a variable number of clamps on their haptor ; each clamp is attached to the host fish, generally to its gill. Clamps include sclerotised elements, called the sclerites, and muscles. The structure of clamps varies according to the groups within the Polyopisthocotylean monogeneans; microcotylids have relatively simple clamps, whereas gastrocotylids have more complex clamps.
A sclerite is a hardened body part. In various branches of biology the term is applied to various structures, but not as a rule to vertebrate anatomical features such as bones and teeth. Instead it refers most commonly to the hardened parts of arthropod exoskeletons and the internal spicules of invertebrates such as certain sponges and soft corals. In paleontology, a scleritome is the complete set of sclerites of an organism, often all that is known from fossil invertebrates.
Justine et al.observed that protomicrocotylids had specialized structures associated with their attachment organ, such as lateral flaps and transverse striations, which were not known in other monogeneans. They hypothesized that the clamps in protomicrocotylids were sequentially lost during evolution, coinciding with the development of other attachment structures. To test the hypothesis, they calculated the surfaces of clamps and body in 120 species of gastrocotylinean monogeneans. The ratio of clamp surface: body surface was the lowest in protomicrocotylids. They concluded that clamps in protomicrocotylids were vestigial organs, and that occurrence of gastrocotylid and simpler microcotylid clamps within the same family were steps in an evolutionary sequence, leading to the absence of these attributes in species of Lethacotyle .
Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes that are passed on from parent to offspring during reproduction. Different characteristics tend to exist within any given population as a result of mutation, genetic recombination and other sources of genetic variation. Evolution occurs when evolutionary processes such as natural selection and genetic drift act on this variation, resulting in certain characteristics becoming more common or rare within a population. It is this process of evolution that has given rise to biodiversity at every level of biological organisation, including the levels of species, individual organisms and molecules.
Vestigiality is the retention during the process of evolution of genetically determined structures or attributes that have lost some or all of their ancestral function in a given species. Assessment of the vestigiality must generally rely on comparison with homologous features in related species. The emergence of vestigiality occurs by normal evolutionary processes, typically by loss of function of a feature that is no longer subject to positive selection pressures when it loses its value in a changing environment. The feature may be selected against more urgently when its function becomes definitively harmful, but if the lack of the feature provides no advantage, and its presence provides no disadvantage, the feature may not be phased out by natural selection and persist across species.
Lethacotyle is a genus of polyopisthocotylean monogeneans, included in the family Protomicrocotylidae.
The genus includes only two species: Lethacotyle fijiensisManter & Price, 1953 , the type-species of the genus, and Lethacotyle veraJustine, Rahmouni, Gey, Schoelinck, & Hoberg, 2013 . Both species are parasitic on the gills of jacks in the Pacific Ocean. They are known only from three localities: off Fiji, Andaman Islands, and New Caledonia.
The genus Lethacotyle is special in that its members have no clamps on their posterior attachment organ or haptor, in contrast to most polyopisthocotylean Monogenean which have clamps. This is reflected in the etymology of the name, which, according to Manter & Price is "from letha = forgetting, and cotyle = cup, and refers to the absence of clamps".
Protomicrocotylids are all parasitic on gills of teleost fish, of only two families, the Carangidae (jacks) and Sphyraenidae (barracudas).
MacCallum (1918) found many worms on the gills of a crevalle jack and noted that he had "no doubt that at times the species may be a serious menace to the life of the fish".
A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water and excretes carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are kept moist. The microscopic structure of a gill presents a large surface area to the external environment. Branchia is the zoologists' name for gills.
The Carangidae are a family of fish which includes the jacks, pompanos, jack mackerels, runners, and scads.
Microcotyle is a genus which belongs to the phylum Platyhelminthes and class Monogenea. Species of Microcotyle are ectoparasites that affect their host by attaching themselves as larvae on the gills of the fish and grow into adult stage. This larval stage is called oncomiracidium, and is characterized as free swimming and ciliated.
Lethacotyle fijiensis is a species of monogeneans of the family Protomicrocotylidae.
Lethacotyle vera is a species of monogenean of the family Protomicrocotylidae.
The Diplectanidae are a family of monopisthocotylean monogeneans. They are all parasitic on the gills of fish. Diplectanids are small animals, generally around 1 mm in length. As parasites, they can be extremely numerous, up to several thousand on an individual fish.
Microcotyle argenticus is a species of monogenean, parasitic on the gills of a marine fish. It belongs to the family Microcotylidae. It was described from the gills of the silver pomfret Pampus argenteus (Stromateidae) from Karachi coast off Pakistan.
Microcotyle bothi is a species of monogenean, parasitic on the gills of a marine fish collected in Hawaii. It belongs to the family Microcotylidae.
Microcotyle poronoti is a species of monogenean, parasitic on the gills of a marine fish. It belongs to the family Microcotylidae.
Microcotyle constricta is a species of monogenean, parasitic on the gills of a marine fish. It belongs to the family Microcotylidae..
Microcotyle centrodonti is a species of monogenean, parasitic on the gills of a marine fish. It belongs to the family Microcotylidae.
Microcotyle emmelichthyops is a species of monogenean, parasitic on the gills of a marine fish in Hawaii. It belongs to the family Microcotylidae.
Microcotyle pempheri is a species of monogenean, parasitic on the gills of a marine fish. It belongs to the family Microcotylidae.
Microcotyle jonii is a species of monogenean, parasitic on the gills of a marine fish. It belongs to the family Microcotylidae. It was described from the gills of Lutjanus jonii (Lutjanidae) from Karachi coast off Pakistan.
Microcotyle pontica is a species of monogenean, parasitic on the gills of a marine fish. It belongs to the family Microcotylidae. It was first described and illustrated from the gills of the east Atlantic peacock wrasse Symphodus tinca (Labridae), from the Black sea.
Microcotyle inglisi is a species of monogenean, parasitic on the gills of a marine fish. It belongs to the family Microcotylidae. It was first described and illustrated based on 5 specimens from the gills of the Indian mackerel Scomber microlepidotus (Scombridae) off Odisha, India..
Microcotyle korathai is a species of monogenean, parasitic on the gills of a marine fish. It belongs to the family Microcotylidae. It was first described and illustrated based on 6 specimens from the gills of the Indian mackerel Scomber microlepidotus (Scombridae) off Odisha, India..
Pseudaxine is a genus which belongs to the phylum Platyhelminthes and class Monogenea; all its species are parasites of fish.
Pseudaxine indicana is a species of monogenean flatworm, which is parasitic on the gills of a marine fish. It belongs to the family Gastrocotylidae.
Sibitrema is a genus which belongs to the phylum Platyhelminthes and class Monogenea; the only species included in this genus is parasite of fish.
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