''Pseudoceros'' is a genus of the flatworms

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 ...

Description

Easily recognized features within the genus include a ruffled

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 ...

, branched intestines, and tentacles on the leading edge. The tentacles may act as

chemoreceptors A chemoreceptor, also known as chemosensor, is a specialized sensory receptor which transduces a chemical substance (endogenous or induced) to generate a biological signal. This signal may be in the form of an action potential, if the chemorecept ...

and may also have primitive eyes, simple light-sensitive cells, on them. The Polyclad worms are

acoelomates The coelom (or celom) is the main body cavity in most animals and is positioned inside the Body (biology), body to surround and contain the digestive tract and other Organ (biology), organs. In some animals, it is lined with mesothelium. In other ...

and

bilaterally symmetrical Symmetry in biology refers to the symmetry observed in organisms, including plants, animals, fungi, and bacteria. External symmetry can be easily seen by just looking at an organism. For example, take the face of a human being which has a pla ...

. Color is the main identifier within the family

Pseudocerotidae Pseudocerotidae is a family of flatworms which includes the Bedford's flatworm. Pseudocerotidae are simple organisms categorized by their oval bodies and tentacles and bright colors. They use the cilia to glide along surfaces. Most commonly refer ...

to separate it into genera, as it can be difficult to distinguish internal reproductive anatomy between genera. Because of the similarities in body plan and structure, it is assumed that chemical cues are how these organisms can recognize their own species and differentiate between others. The intense coloring and patterning on these flatworms could be used to camouflage with their surroundings, confuse and elude predators, to communicate with other members of the species, or as

aposematism Aposematism is the advertising by an animal to potential predators that it is not worth attacking or eating. This unprofitability may consist of any defences which make the prey difficult to kill and eat, such as toxicity, venom, foul taste or ...

to warn predators of their deadly toxins. The cells and the pigments they contain that are responsible for this coloring have not been well-studied, but one common theory is that they may be

ommochrome Ommochrome (or visual pigment) refers to several biological pigments that occur in the eyes of crustaceans and insects. The eye color is determined by the ommochromes. Ommochromes are also found in the chromatophores of cephalopods, and in spiders ...

pigments, although no discoveries have been made to prove this.

Distribution

''Pseudoceros'' are generally found in tropical and subtropical waters. They are populous in the

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

region and have been found as far north as

Puget Sound Puget Sound ( ) is a sound of the Pacific Northwest, an inlet of the Pacific Ocean, and part of the Salish Sea. It is located along the northwestern coast of the U.S. state of Washington. It is a complex estuarine system of interconnected ma ...

, where '' Pseudoceros canadensis'' has been identified, but mostly tend to stay in warmer waters.

Reproduction

''Pseudoceros'' are simultaneous hermaphrodites and reproduce sexually via random

hypodermic insemination Traumatic insemination, also known as hypodermic insemination, is the mating practice in some species of invertebrates in which the male pierces the female's abdomen with his aedeagus and injects his sperm through the wound into her abdominal ca ...

through the body tissue. These organisms participate in

penis fencing __NOTOC__ Penis fencing is a mating behavior engaged in by many species of flatworm, such as '' Pseudobiceros hancockanus''. Species which engage in the practice are hermaphroditic; each individual has both egg-producing ovaries and sperm-produci ...

, which is a behavior where the flatworms use their extended penises to stab and inseminate the other, while avoiding becoming inseminated themselves. After successful fertilization, these flatworms are known to lay egg masses on the

benthos Benthos (), also known as benthon, is the community of organisms that live on, in, or near the bottom of a sea, river, lake, or stream, also known as the benthic zone. Numbers of eggs, egg size, and developmental time vary between species. ''Pseudoceros'' ''indicus'' will display parental care in the form of

brooding Egg incubation is the process by which an egg, of oviparous (egg-laying) animals, develops an embryo within the egg, after the egg's formation and ovipositional release. Egg incubation is done under favorable environmental conditions, possib ...

activity. ''Pseudoceros'' will hatch into Muller's larvae and undergo indirect development and

metamorphosis Metamorphosis is a biological process by which an animal physically develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some inse ...

before becoming an adult organism.

History & taxonomy

Historically, studying flatworms has been a time and labor-intensive job, generally done through live drawings of specimens, preservation of hard parts (which led to the loss of important information pertaining to the soft parts), and very detailed anatomical studies based on serial sections. More recent technological advances have allowed for scientists to combine

photomicrography A micrograph or photomicrograph is a photograph or digital image taken through a microscope or similar device to show a magnified image of an object. This is opposed to a macrograph or photomacrograph, an image which is also taken on a mi ...

with molecular analyses to more easily study these organisms. There is currently no consensus on what the best method of identification for ''Pseudoceros'' is. The two main theories are that species can be identified solely based on their color patterns and that species should be identified based on their reproductive organs instead of coloration. Because of this, identification methods vary within the biological community. In concordance with the theory that species should be identified based on color patterns, a new method for preserving ''Pseudoceros'' samples was developed in 1995 by Cannon and Newman. This method utilizes FCA-PGPP, or Formaldehyde Calcium Acetate-Propylene Glycol, Propylene Phenoxetol, as the fixative. The worms are placed onto filter paper which is placed on top of a frozen layer of the fixative, and this preserves color accurately. As of 2000, there are 13 genera in the family

that comprise an estimated at least 500 species, of which the genus ''Pseudoceros'' made up about 75% until the genus ''

Pseudobiceros ''Pseudobiceros'' is a genus of flatworms. Like all flatworms, Pseudobiceros are hermaphrodites. This particular genus engages in penis fencing. When the "winner" touches its penis to the "skin" of the other, insemination occurs, and the "loser" ...

'' was separated.

Species

The following species are recognised in the genus ''Pseudoceros'': *''

Pseudoceros affinis ''Pseudoceros'' is a genus of the flatworms Platyhelminthes. Description Easily recognized features within the genus include a ruffled pharynx, branched intestines, and tentacles on the leading edge. The tentacles may act as chemoreceptors ...

'' (Collingwood, 1876) *''

Pseudoceros agattiensis ''Pseudoceros'' is a genus of the flatworms Platyhelminthes. Description Easily recognized features within the genus include a ruffled pharynx, branched intestines, and tentacles on the leading edge. The tentacles may act as chemoreceptors ...

'' Dixit, 2019 *''

Pseudoceros albicornus ''Pseudoceros'' is a genus of the flatworms Platyhelminthes. Description Easily recognized features within the genus include a ruffled pharynx, branched intestines, and tentacles on the leading edge. The tentacles may act as chemoreceptors ...

'' (Stimpson, 1857) *'' Pseudoceros albomarginatus''

Hyman Surname Hyman is the surname of: * Alan Hyman (1910–1999), author and screenwriter * Alexander C. Hyman (Born 1993), American Businessman * Albert Hyman (1893–1972), co-inventor of the artificial pacemaker * Anthony Hyman (disambiguation), se ...

, 1959 *'' Pseudoceros asamusiensis'' Kato, 1939 *'' Pseudoceros astrorum'' Bulnes & Torres, 2014 *'' Pseudoceros ater''

, 1959 *'' Pseudoceros atraviridis'' (Collingwood, 1876) *'' Pseudoceros atropurpureus'' Kato, 1934 *'' Pseudoceros auranticrinis'' Dixit, Raghunathan & Chandra, 2017 *'' Pseudoceros bicolor'' Verrill, 1902 *'' Pseudoceros bicuti'' Ramos-Sanchez, Bahia & Rolando Bastida-Zavala, 2020 *'' Pseudoceros bifasciatus'' Prudhoe, 1989 *'' Pseudoceros bimarginatus'' Meixner, 1907 *'' Pseudoceros bipurpureus'' Dixit, 2021 *'' Pseudoceros bolool'' Newman & Cannon, 1994 *'' Pseudoceros buskii'' (Collingwood, 1876) *'' Pseudoceros caeruleocinctus'' Hyman, 1959 *'' Pseudoceros caeruleopunctatus'' Palombi, 1928 *'' Pseudoceros canadensis''

, 1953 *'' Pseudoceros cardinalis'' Haswell, 1907 *'' Pseudoceros cardiosorus'' (

Schmarda Ludwig Karl Schmarda (23 August 1819 – 7 April 1908) was an Austrian naturalist and traveler, born at Olmütz, Moravia. Early life and education Schmarda was born at Olmütz where he attended the Grammar School and the Philosophical Course a ...

, 1859) *'' Pseudoceros cerebralis'' (Kelaart, 1858) *'' Pseudoceros chloreus'' Marcus, 1949 *'' Pseudoceros clavicornis'' (

, 1859) *'' Pseudoceros coccineus'' (Stimpson, 1857) *'' Pseudoceros colemani'' Prudhoe, 1977 *'' Pseudoceros collingwoodi'' Laidlaw, 1903 *'' Pseudoceros concinnus'' ( Collingwood, 1876) *'' Pseudoceros confusus'' Newman & Cannon, 1995 *'' Pseudoceros contrarius'' Newman & Cannon, 1995 *'' Pseudoceros corallophilus'' Hyman, 1954 *'' Pseudoceros cruentus'' Newman & Cannon, 1998 *'' Pseudoceros devisii'' Woodworth, 1898 *'' Pseudoceros dimidiatus'' von Graff, 1893 *'' Pseudoceros dulcis'' Kelaart, 1858 *'' Pseudoceros duplicinctus'' Prudhoe, 1989 *'' Pseudoceros exoptatus'' Kato, 1938 *'' Pseudoceros felis'' Newman & Cannon, 1994 *'' Pseudoceros ferrugineus'' (

, 1959) *'' Pseudoceros flavomaculatus'' Graff, 1893 *'' Pseudoceros flavomarginatus'' Laidlaw, 1902 *'' Pseudoceros fulminatus'' (Stimpson, 1855) *'' Pseudoceros fuscogriseus''

, 1959 *'' Pseudoceros fuscopunctatus'' Prudhoe, 1977 *'' Pseudoceros fuscus'' (Kelaart, 1858) *'' Pseudoceros galatheensis'' Dixit, Raghunathan & Chandra, 2017 *'' Pseudoceros galaxea'' Dixit, 2021 *'' Pseudoceros gamblei'' Laidlaw, 1902 *'' Pseudoceros glaucus'' Prudhoe, 1989 *'' Pseudoceros goslineri'' Newman & Cannon, 1994 *'' Pseudoceros gravieri'' Meixner, 1907 *'' Pseudoceros griseus''

, 1959 *'' Pseudoceros guttatomarginatus'' (Stimpson, 1855) *'' Pseudoceros habroptilus'' Hyman, 1959 *'' Pseudoceros haddoni'' (Laidlaw, 1903) *'' Pseudoceros hancockanus'' (Collingwood, 1876) *'' Pseudoceros harrisi'' Bolanos, Quiroga, & Litvaitis, 2007 *'' Pseudoceros heronensis'' Newman & Cannon, 1994 *'' Pseudoceros imitatus'' Newman & Cannon, 1994 *'' Pseudoceros imperatus'' Newman & Cannon, 1998 *'' Pseudoceros indicus'' Newman & Schupp, 2002 *'' Pseudoceros intermittus'' Newman & Cannon, 1995 *'' Pseudoceros interruptus'' (Stimpson, 1855) *'' Pseudoceros irretitus'' Newman & Cannon, 1998 *'' Pseudoceros japonicus'' (Stimpson, 1857) *'' Pseudoceros jebborum'' Newman & Cannon, 1994 *'' Pseudoceros josei'' Newman & Cannon, 1998 *'' Pseudoceros juani'' Bahia et al., 2014 *'' Pseudoceros kelaarti'' (Collingwood, 1876) *'' Pseudoceros kentii'' Graff, 1893 *'' Pseudoceros kylie'' Newman & Cannon, 1998 *'' Pseudoceros lacteus'' ( Collingwood, 1876) *'' Pseudoceros lactolimbus'' Newman & Cannon, 1998 *'' Pseudoceros laingensis'' Newman & Cannon, 1998 *'' Pseudoceros langamaakensis'' Faubel, 1983 *'' Pseudoceros laticlavus'' Newman & Cannon, 1994 *'' Pseudoceros latissimus type A'' (

, 1859) *'' Pseudoceros leptostictus'' Bock, 1913 *'' Pseudoceros limbatus'' Leuckart, 1828 *'' Pseudoceros lindae'' Newman & Cannon, 1994 *''

Pseudoceros liparus ''Pseudoceros bifurcus'' is a marine flatworm species that belongs to the family Pseudocerotidae. Common name Racing stripe flatworm, orange-band flatworm, orange tipped flatworm. Distribution Tropical Indo-Pacific, from eastern coast of A ...

'' Marcus, 1950 *'' Pseudoceros litoralis'' Bock, 1913 *''

Pseudoceros lividus ''Pseudoceros'' is a genus of the flatworms Platyhelminthes. Description Easily recognized features within the genus include a ruffled pharynx, branched intestines, and tentacles on the leading edge. The tentacles may act as chemoreceptors ...

'' Prudhoe, 1982 *'' Pseudoceros luteus'' (Plehn, 1898) *'' Pseudoceros macroceraeus''

, 1859 *'' Pseudoceros maculatus'' (Pease, 1860) *'' Pseudoceros maximum'' Lang, 1884 *'' Pseudoceros maximus-type A'' Lang, 1884 *'' Pseudoceros meenae'' Dixit, Sivaperuman & Raghunathan, 2018 *'' Pseudoceros memoralis'' Kato, 1938 *'' Pseudoceros mexicanus'' Hyman, 1953 *'' Pseudoceros microceraeus'' (

, 1859) *'' Pseudoceros micropapillosus'' Kato, 1934 *'' Pseudoceros monostichos'' Newman & Cannon, 1994 *'' Pseudoceros montereyensis'' Hyman, 1953 *'' Pseudoceros mossambicus'' Prudhoe, 1989 *'' Pseudoceros mulleri'' (Delle Chiaje, 1829) *'' Pseudoceros niger'' (Stimpson, 1857) *'' Pseudoceros nigrocinctus'' (

, 1859) *'' Pseudoceros nigropunctatus'' Dixit, Raghunathan & Chandra, 2017 *'' Pseudoceros nipponicus'' Kato, 1944 *'' Pseudoceros ouini'' Newman & Cannon, 1994 *'' Pseudoceros paradoxus'' Bock, 1927 *'' Pseudoceros paralaticlavus'' Newman & Cannon, 1994 *'' Pseudoceros periaurantius'' Newman & Cannon, 1994 *'' Pseudoceros periphaeus'' Bock, 1913 *'' Pseudoceros peripurpureus'' Newman & Cannon, 1994 *'' Pseudoceros perviolaceus'' (

, 1859) *'' Pseudoceros pius'' Kato, 1938 *'' Pseudoceros pleurostictus'' Bock, 1913 *'' Pseudoceros punctatus'' Laidlaw, 1902 *'' Pseudoceros purpureus'' (Kelaart, 1858) *'' Pseudoceros rawlinsonae'' Bolanos, Quiroga, & Litvaitis, 2007 *'' Pseudoceros regalus'' Laidlaw, 1903 *'' Pseudoceros reticulatus'' Yeri & Kaburaki, 1918 *'' Pseudoceros rubellus'' Laidlaw, 1903 *'' Pseudoceros rubronanus'' Newman & Cannon, 1998 *'' Pseudoceros rubrotentaculatus'' Kaburaki, 1923 *'' Pseudoceros sagamianus'' Kato, 1937 *'' Pseudoceros sapphirinus'' Newman & Cannon, 1994 *'' Pseudoceros scintillatus'' Newman & Cannon, 1994 *'' Pseudoceros scriptus'' Newman & Cannon, 1998 *'' Pseudoceros stellans'' Dixit, 2019 *'' Pseudoceros stimpsoni'' Newman & Cannon, 1998 *'' Pseudoceros striatus'' Kelaart, 1858 *'' Pseudoceros susanae'' Newman & Anderson, 1997 *'' Pseudoceros texanus''

, 1955 *'' Pseudoceros tigrinus'' Laidlaw, 1902 *'' Pseudoceros tomiokaensis'' Kato, 1938 *'' Pseudoceros tristriatus'' Hyman, 1959 *'' Pseudoceros velutinus'' (

Blanchard Blanchard is a French family name. It is also used as a given name. It derives from the Old French word ''blanchart'' which meant "whitish, bordering upon white". It is also an obsolete term for a white horse. Geographical distribution As of 2014, ...

, 1847) *'' Pseudoceros verecundus'' Newman & Cannon, 1994 *'' Pseudoceros vinosus'' Meixner, 1907 *'' Pseudoceros vishnui'' Dixit, Raghunathan & Chandra, 2017 *'' Pseudoceros yessoensis'' Kato, 1937 *'' Pseudoceros zebra'' (Leuckart, 1828) *'' Pseudoceros zeylanicus'' (Kelaart, 1858)

References

External links

* * {{Taxonbar, from=Q1941954 Turbellaria genera