acoel
Acoela, or the acoels, is an order of small and simple invertebrates in the subphylum Acoelomorpha of phylum Xenacoelomorpha, a deep branching bilaterian group of animals, which resemble flatworms. Historically they were treated as an order of ...
s. It contains more than a third of all known acoel species.Turbellarian taxonomic database 2006.
Description
The family Convolutidae includes acoels with a ventral mouth opening and a body-wall musculature composed both dorsally and ventrally by circular, longitudinal, and longitudinal crossover muscle fibers. The ventral body wall also has a group of U-shaped fibers. Most species are
symbiont
Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...
s with
alga
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mi ...
e. The anterior end has a cluster of frontal glands, a pair of eyes and a statocyst. The body has pigmented lens. Intestine and excretory system is absent. It is hermaphrodite but
protandry
Sequential hermaphroditism (called dichogamy in botany) is a type of hermaphroditism that occurs in many fish, gastropods, and plants. Sequential hermaphroditism occurs when the individual changes its sex at some point in its life. In particular, ...
is common.
Taxonomy
Genera
There are 25 genera in the family Convolutidae.Nilsson, K.S., Wallberg, A., & Jondelius, U. (2011). "New species of Acoela from the Mediterranean, the Red Sea, and the South Pacific." ''Zootaxa'' 2867: 1-31. The
type genus
In biological taxonomy, the type genus is the genus which defines a biological family and the root of the family name.
Zoological nomenclature
According to the International Code of Zoological Nomenclature, "The name-bearing type of a nominal f ...
is ''Convoluta''.
* ''
Achoerus
''Achoerus'' is a genus of worms belonging to the family Convolutidae
Convolutidae is a family of acoels. It contains more than a third of all known acoel species.Adenopea
''Adenopea'' is a genus of worms belonging to the family Convolutidae
Convolutidae is a family of acoels. It contains more than a third of all known acoel species.Amphiscolops
''Amphiscolops'' is a genus of acoels belonging to the family Convolutidae
Convolutidae is a family of acoels. It contains more than a third of all known acoel species.Antrosagittifera'' Hooge & Tyler, 2001
* ''
Brachypea
''Brachypea'' is a genus of worms belonging to the family Convolutidae
Convolutidae is a family of acoels. It contains more than a third of all known acoel species.Conaperta
''Conaperta'' is a genus of worms belonging to the family Convolutidae
Convolutidae is a family of acoels. It contains more than a third of all known acoel species.Convoluta
Convolutidae is a family of acoels. It contains more than a third of all known acoel species.Turbellaria ...
'' Ørsted, 1843
* ''
Convolutriloba
Convolutriloba is a genus of marine acoelomorph worms.
They possess shield shaped bodies with a rounded anterior and three caudal lobes, though the number may vary in mature individuals. They may have an indentation on each side of the body near ...
'' Hendelberg & Akesson, 1988
* ''
Haplodiscus
''Haplodiscus'' is a genus of acoels belonging to the family Convolutidae
Convolutidae is a family of acoels. It contains more than a third of all known acoel species.Heterochaerus
''Heterochaerus'' is a genus of worms belonging to the family Convolutidae
Convolutidae is a family of acoels. It contains more than a third of all known acoel species.Neochildia
''Neochildia'' is a monotypic genus of a dark brown acoel belonging to the family Convolutidae. The only species is ''Neochildia fusca''.
The nervous system is composed of an anterior compact brain organized as a layer of neural somata surroundi ...
Symsagittifera
''Symsagittifera'' is a genus of worms belonging to the family Convolutidae.
The species of this genus are found in West Europe and South Africa.
Species:
*'' Symsagittifera bifoveolata''
*'' Symsagittifera corsicae''
*'' Symsagittifera japon ...
'' Kostenko & Mamkaev, 1990
* ''
Thalassoanaperus
''Thalassoanaperus'' is a genus of worms belonging to the family Convolutidae
Convolutidae is a family of acoels. It contains more than a third of all known acoel species.
'' Hernandez, 2018
* ''
Waminoa
''Waminoa'' is a genus of acoels which are epizoic on living corals, using the coral's mucus as a source of food. Unusually, these acoels harbor two genera of endosymbiotic dinoflagellates: ''Symbiodinium'' and '' Amphidinium''; it is not typical ...
There are over 100 species recognised in the family Convolutidae:
* ''
Achoerus caspius
''Achoerus'' is a genus of worms belonging to the family Convolutidae.
Species:
* '' Achoerus caspius'' Beklemischev, 1914
* ''Achoerus ferox
''Achoerus'' is a genus of worms belonging to the family Convolutidae
Convolutidae is a family ...
'' Beklemischev, 1914
* ''
Achoerus ferox
''Achoerus'' is a genus of worms belonging to the family Convolutidae
Convolutidae is a family of acoels. It contains more than a third of all known acoel species.Achoerus pachycaudatus
''Achoerus'' is a genus of worms belonging to the family Convolutidae.
Species:
* ''Achoerus caspius'' Beklemischev, 1914
* ''Achoerus ferox
''Achoerus'' is a genus of worms belonging to the family Convolutidae
Convolutidae is a family ...
'' Dörjes, 1968
* ''
Adenopea cenata
''Adenopea'' is a genus of worms belonging to the family Convolutidae
Convolutidae is a family of acoels. It contains more than a third of all known acoel species.Adenopea chuni
''Adenopea'' is a genus of worms belonging to the family Convolutidae.
Species:
*''Adenopea cenata''
*'' Adenopea chuni''
*'' Adenopea illardata''
*''Adenopea illardatus
''Adenopea'' is a genus of worms belonging to the family Convolutida ...
'' (Brauner, 1920)
* ''
Adenopea illardata
''Adenopea'' is a genus of worms belonging to the family Convolutidae.
Species:
*''Adenopea cenata''
*''Adenopea chuni''
*'' Adenopea illardata''
*''Adenopea illardatus
''Adenopea'' is a genus of worms belonging to the family Convolutidae ...
'' Löhner & Micoletzky, 1911
* ''
Adenopea illardatus
''Adenopea'' is a genus of worms belonging to the family Convolutidae.
Species:
*''Adenopea cenata
''Adenopea'' is a genus of worms belonging to the family Convolutidae
Convolutidae is a family of acoels. It contains more than a third of ...
'' (Lohner & Micoletzky, 1911)
* ''
Amphiscolops bermudensis
''Amphiscolops'' is a genus of acoels belonging to the family Convolutidae.
The species of this genus are found in America.
Species
The following species are recognised in the genus ''Amphiscolops'':
*'' Amphiscolops bermudensis''
*'' Amphisco ...
'' Hyman 1939
* ''
Amphiscolops castellonensis
''Amphiscolops'' is a genus of acoels belonging to the family Convolutidae.
The species of this genus are found in America.
Species
The following species are recognised in the genus ''Amphiscolops'':
*''Amphiscolops bermudensis''
*'' Amphiscol ...
'' Steinböck, 1954
* ''
Amphiscolops cinereus
''Amphiscolops'' is a genus of acoels belonging to the family Convolutidae
Convolutidae is a family of acoels. It contains more than a third of all known acoel species.Amphiscolops evelinae
''Amphiscolops'' is a genus of acoels belonging to the family Convolutidae.
The species of this genus are found in America.
Species
The following species are recognised in the genus ''Amphiscolops'':
*''Amphiscolops bermudensis''
*''Amphiscolo ...
'' Marcus 1947
* ''
Amphiscolops fuligineus
''Amphiscolops'' is a genus of acoels belonging to the family Convolutidae.
The species of this genus are found in America.
Species
The following species are recognised in the genus ''Amphiscolops'':
*''Amphiscolops bermudensis''
*''Amphiscolo ...
'' Peebles 1913
* ''
Amphiscolops gemelliporus
''Amphiscolops'' is a genus of acoels belonging to the family Convolutidae.
The species of this genus are found in America.
Species
The following species are recognised in the genus ''Amphiscolops'':
*''Amphiscolops bermudensis''
*''Amphiscolo ...
'' Marcus 1954
* ''
Amphiscolops gerundensis
''Amphiscolops'' is a genus of acoels belonging to the family Convolutidae.
The species of this genus are found in America.
Species
The following species are recognised in the genus ''Amphiscolops'':
*''Amphiscolops bermudensis''
*''Amphiscolo ...
'' Steinböck, 1954
* ''
Amphiscolops japonicus
''Amphiscolops'' is a genus of acoels belonging to the family Convolutidae.
The species of this genus are found in America.
Species
The following species are recognised in the genus ''Amphiscolops'':
*''Amphiscolops bermudensis''
*''Amphiscolo ...
'' Kato 1947
* ''
Amphiscolops marinelliensis
''Amphiscolops'' is a genus of acoels belonging to the family Convolutidae.
The species of this genus are found in America.
Species
The following species are recognised in the genus ''Amphiscolops'':
*''Amphiscolops bermudensis''
*''Amphiscolo ...
'' Beltagi & Khafagi, 1984
* ''
Amphiscolops mosaicus
''Amphiscolops'' is a genus of acoels belonging to the family Convolutidae.
The species of this genus are found in America.
Species
The following species are recognised in the genus ''Amphiscolops'':
*''Amphiscolops bermudensis''
*''Amphiscolo ...
'' Kozloff 1998
* ''
Amphiscolops potocani
''Amphiscolops'' is a genus of acoels belonging to the family Convolutidae.
The species of this genus are found in America.
Species
The following species are recognised in the genus ''Amphiscolops'':
*''Amphiscolops bermudensis''
*''Amphiscolo ...
'' Achatz, 2008
* ''
Amphiscolops trifurcatus
''Amphiscolops'' is a genus of acoels belonging to the family Convolutidae.
The species of this genus are found in America.
Species
The following species are recognised in the genus ''Amphiscolops'':
*''Amphiscolops bermudensis''
*''Amphiscolo ...
Conaperta antonii
''Conaperta'' is a genus of worms belonging to the family Convolutidae
Convolutidae is a family of acoels. It contains more than a third of all known acoel species.Conaperta cirrata
''Conaperta'' is a genus of worms belonging to the family Convolutidae.
Species:
*''Conaperta antonii
''Conaperta'' is a genus of worms belonging to the family Convolutidae
Convolutidae is a family of acoels. It contains more than a third o ...
'' Achatz, Hooge & Tyler, 2007
* ''
Conaperta flavibacillum
''Conaperta'' is a genus of worms belonging to the family Convolutidae.
Species:
*''Conaperta antonii''
*''Conaperta cirrata
''Conaperta'' is a genus of worms belonging to the family Convolutidae.
Species:
*''Conaperta antonii
''Conaperta ...
'' (Jensen, 1878)
* ''
Conaperta lineata
''Conaperta'' is a genus of worms belonging to the family Convolutidae.
Species:
*''Conaperta antonii''
*''Conaperta cirrata''
*''Conaperta flavibacillum
''Conaperta'' is a genus of worms belonging to the family Convolutidae.
Species:
*''C ...
Convolutriloba retrogemma
''Convolutriloba retrogemma'' is a reddish-brown flatworm 2 mm in length also commonly known as redbug, red planaria, rust flatworm, or simply red flatworm. It is a marine flatworm that gets energy from its endosymbiotic algae or from the ...
'' Hendelberg & Akesson, 1988
* ''
Haplodiscus acuminatus
''Haplodiscus'' is a genus of acoels belonging to the family Convolutidae.
Species:
*'' Haplodiscus acuminatus''
*'' Haplodiscus bocki''
*''Haplodiscus incola
''Haplodiscus'' is a genus of acoels belonging to the family Convolutidae
Con ...
'' Böhmig, 1895
* ''
Haplodiscus bocki
''Haplodiscus'' is a genus of acoels belonging to the family Convolutidae.
Species:
*''Haplodiscus acuminatus''
*'' Haplodiscus bocki''
*''Haplodiscus incola
''Haplodiscus'' is a genus of acoels belonging to the family Convolutidae
Conv ...
'' Dörjes 1970
* ''
Haplodiscus incola
''Haplodiscus'' is a genus of acoels belonging to the family Convolutidae
Convolutidae is a family of acoels. It contains more than a third of all known acoel species.Haplodiscus obtusus
''Haplodiscus'' is a genus of acoels belonging to the family Convolutidae.
Species:
*''Haplodiscus acuminatus''
*''Haplodiscus bocki''
*''Haplodiscus incola
''Haplodiscus'' is a genus of acoels belonging to the family Convolutidae
Convo ...
'' Böhmig, 1895
* ''
Haplodiscus ovatus
''Haplodiscus'' is a genus of acoels belonging to the family Convolutidae.
Species:
*''Haplodiscus acuminatus''
*''Haplodiscus bocki''
*''Haplodiscus incola''
*''Haplodiscus obtusus
''Haplodiscus'' is a genus of acoels belonging to the fa ...
'' Böhmig, 1895
* ''
Haplodiscus piger
''Haplodiscus'' is a genus of acoels belonging to the family Convolutidae.
Species:
*''Haplodiscus acuminatus''
*''Haplodiscus bocki''
*''Haplodiscus incola''
*''Haplodiscus obtusus''
*''Haplodiscus ovatus
''Haplodiscus'' is a genus of a ...
'' Weldon 1888
* ''
Haplodiscus ussovi
''Haplodiscus'' is a genus of acoels belonging to the family Convolutidae.
Species:
*''Haplodiscus acuminatus''
*''Haplodiscus bocki''
*''Haplodiscus incola''
*''Haplodiscus obtusus''
*''Haplodiscus ovatus''
*''Haplodiscus piger
''Haplo ...
'' Sabussow, 1896
* ''
Haplodiscus weldoni
''Haplodiscus'' is a genus of acoels belonging to the family Convolutidae.
Species:
*''Haplodiscus acuminatus''
*''Haplodiscus bocki''
*''Haplodiscus incola''
*''Haplodiscus obtusus''
*''Haplodiscus ovatus''
*''Haplodiscus piger''
*''Hapl ...
'' Böhmig, 1895
* ''
Heterochaerus australis
''Heterochaerus'' is a genus of worms belonging to the family Convolutidae
Convolutidae is a family of acoels. It contains more than a third of all known acoel species.Heterochaerus blumi
''Heterochaerus'' is a genus of worms belonging to the family Convolutidae.
The species of this genus are found in Australia and Central America.
Species:
*''Heterochaerus australis
''Heterochaerus'' is a genus of worms belonging to the famil ...
'' (Achatz, Hooge & Tyler, 2007)
* ''
Heterochaerus carvalhoi
''Heterochaerus'' is a genus of worms belonging to the family Convolutidae.
The species of this genus are found in Australia and Central America.
Species:
*''Heterochaerus australis''
*''Heterochaerus blumi
''Heterochaerus'' is a genus of wo ...
'' (Marcus, 1952)
* ''
Heterochaerus langerhansi
''Heterochaerus'' is a genus of worms belonging to the family Convolutidae.
The species of this genus are found in Australia and Central America.
Species:
*''Heterochaerus australis''
*''Heterochaerus blumi''
*''Heterochaerus carvalhoi
''He ...
'' (Graff, 1882)
* ''
Heterochaerus sargassi
''Heterochaerus'' is a genus of worms belonging to the family Convolutidae.
The species of this genus are found in Australia and Central America.
Species:
*''Heterochaerus australis''
*''Heterochaerus blumi''
*''Heterochaerus carvalhoi''
*'' ...
'' (Hyman 1939)
* ''
Neochildia fusca
''Neochildia'' is a monotypic genus of a dark brown acoel belonging to the family Convolutidae. The only species is ''Neochildia fusca''.
The nervous system is composed of an anterior compact brain organized as a layer of neural somata surroundi ...
Thalassoanaperus australis
''Thalassoanaperus'' is a genus of worms belonging to the family Convolutidae
Convolutidae is a family of acoels. It contains more than a third of all known acoel species.
'' (Westblad, 1952)
* ''
Thalassoanaperus biaculeatus
''Thalassoanaperus'' is a genus of worms belonging to the family Convolutidae.
?The species of this genus are found in Europe.
Species:
*''Thalassoanaperus australis
''Thalassoanaperus'' is a genus of worms belonging to the family Convolutida ...
'' (Boguta, 1970)
* ''
Thalassoanaperus gardineri
''Thalassoanaperus'' is a genus of worms belonging to the family Convolutidae.
?The species of this genus are found in Europe.
Species:
*''Thalassoanaperus australis''
*''Thalassoanaperus biaculeatus
''Thalassoanaperus'' is a genus of worms ...
'' (Graff, 1911)
* ''
Thalassoanaperus ornatus
''Thalassoanaperus'' is a genus of worms belonging to the family Convolutidae.
?The species of this genus are found in Europe.
Species:
*''Thalassoanaperus australis''
*''Thalassoanaperus biaculeatus''
*''Thalassoanaperus gardineri
''Thalas ...
'' (Beltagi, 2001)
* ''
Thalassoanaperus rubellus
''Thalassoanaperus'' is a genus of worms belonging to the family Convolutidae.
?The species of this genus are found in Europe.
Species:
*''Thalassoanaperus australis''
*''Thalassoanaperus biaculeatus''
*''Thalassoanaperus gardineri''
*''Thal ...
'' (Westblad, 1945)
* ''
Thalassoanaperus singularis
''Thalassoanaperus'' is a genus of worms belonging to the family Convolutidae.
?The species of this genus are found in Europe.
Species:
*''Thalassoanaperus australis''
*''Thalassoanaperus biaculeatus''
*''Thalassoanaperus gardineri''
*''Thal ...
'' (Hooge & Smith, 2004)
* ''
Thalassoanaperus sulcatus
''Thalassoanaperus'' is a genus of worms belonging to the family Convolutidae.
?The species of this genus are found in Europe.
Species:
*''Thalassoanaperus australis''
*''Thalassoanaperus biaculeatus''
*''Thalassoanaperus gardineri''
*''Thal ...
'' (Beklemischev, 1914)
* ''
Thalassoanaperus tvaerminnensis
''Thalassoanaperus'' is a genus of worms belonging to the family Convolutidae.
?The species of this genus are found in Europe.
Species:
*''Thalassoanaperus australis''
*''Thalassoanaperus biaculeatus''
*''Thalassoanaperus gardineri''
*''Thal ...
'' (Luther, 1912)
* ''
Waminoa brickneri
''Waminoa brickneri'' is a newly discovered acoel species from the coral reefs near Eilat (Red Sea) and the second described species in the genus (the first is '' Waminoa litus'').
Characteristics
''Waminoa brickneri'' is discoid to obcordate ...
Waminoa litus
''Waminoa litus'' is a species of dinoflagellate-bearing acoels which are epizoic on living corals. This species is unique in that it transmits its endosymbiotic dinoflagellates (zooxanthellae) vertically (from the parent host to the offspring) ...