''Pseudoceros'' is a genus of the flatworms

Platyhelminthes Platyhelminthes (from the Greek πλατύ, ''platy'', meaning "flat" and ἕλμινς (root: ἑλμινθ-), ''helminth-'', meaning "worm") is a phylum of relatively simple bilaterian, unsegmented, soft-bodied invertebrates commonly called f ...

Description

Easily recognized features within the genus include a ruffled

pharynx The pharynx (: pharynges) is the part of the throat behind the human mouth, mouth and nasal cavity, and above the esophagus and trachea (the tubes going down to the stomach and the lungs respectively). It is found in vertebrates and invertebrates ...

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

chemoreceptor 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 chemorece ...

s 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 many animals and is positioned inside the body to surround and contain the digestive tract and other organs. In some animals, it is lined with mesothelium. In other animals, such as molluscs, it re ...

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, the face of a human being has a plane of symme ...

. Color is the main identifier within the family

Pseudocerotidae Pseudocerotidae is a family of flatworm Platyhelminthes (from the Greek language, Greek πλατύ, ''platy'', meaning "flat" and ἕλμινς (root: ἑλμινθ-), ''helminth-'', meaning "worm") is a Phylum (biology), phylum of relatively ...

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 in biology, advertising by an animal, whether terrestrial or marine, to potential predation, predators that it is not worth attacking or eating. This unprofitability may consist of any defenses which make the pr ...

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 filtering 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 spi ...

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 complex estuary, estuarine system of interconnected Marine habitat, marine waterways and basins located on the northwest coast of the U.S. state of Washington (state), Washington. As a part of the Salish Sea, the sound ...

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

Reproduction

''Pseudoceros'' are

simultaneous hermaphrodite Simultaneous hermaphroditism is one of the two types of hermaphroditism, the other type being sequential hermaphroditism. In this form of hermaphroditism an individual has sex organs of both sexes and can produce both gamete types even in the sa ...

s and reproduce sexually via random hypodermic insemination through the body tissue. These organisms participate in penis fencing, 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 Broodiness is the action or behavioral tendency to sit on a clutch of eggs to Egg incubation, incubate them, often requiring the non-expression of many other behaviors including feeding and drinking.Homedes Ranquini, J. y Haro-García, F. Zoogen� ...

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 transformation or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and different ...

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 is an image, captured photographically or digitally, 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 mic ...

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 Hyman is the surname of: * Alan Hyman (1910–1999), author and screenwriter * Albert Hyman (1893–1972), co-inventor of the artificial pacemaker * Anthony Hyman (disambiguation), several people * Ben Zion Hyman (1891–1984), Canadian-Jewish ...

, 1959 *''

Pseudoceros asamusiensis ''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 ...

'' 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, 1859) *'' Pseudoceros cerebralis'' (Kelaart, 1858) *'' Pseudoceros chloreus'' Marcus, 1949 *'' Pseudoceros clavicornis'' ( Schmarda, 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'' ( Schmarda, 1859) *'' Pseudoceros leptostictus'' Bock, 1913 *'' Pseudoceros limbatus'' Leuckart, 1828 *'' Pseudoceros lindae'' Newman & Cannon, 1994 *''

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

'' Marcus, 1950 *'' Pseudoceros litoralis'' Bock, 1913 *'' Pseudoceros lividus'' Prudhoe, 1982 *'' Pseudoceros luteus'' (Plehn, 1898) *'' Pseudoceros macroceraeus'' Schmarda, 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'' ( Schmarda, 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'' ( Schmarda, 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'' ( Schmarda, 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 ''Pseudoceros'' is a genus of the flatworms Flatworm, 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 chemo ...

'' 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, 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