Anthoathecata, or the athecate hydroids, are an

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...

of hydrozoans belonging to the

phylum In biology, a phylum (; plural: phyla) is a level of classification or taxonomic rank below kingdom and above class. Traditionally, in botany the term division has been used instead of phylum, although the International Code of Nomenclature ...

Cnidaria Cnidaria () is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in freshwater and marine environments, predominantly the latter. Their distinguishing feature is cnidocytes, specialized cells that ...

. A profusion of alternate

scientific name In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bo ...

s exists for this long-known, heavily discussed, and spectacular group. It has also been called Gymnoblastea and (with or without an emended ending ''-ae''), Anthomedusa, Athecata, Hydromedusa, and Stylasterina. There are about 1,200

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

worldwide.Schuchert, P. (2014). Anthoathecata. Accessed through: Schuchert, P. (2014) World Hydrozoa database at http://www.marinespecies.org/hydrozoa/aphia.php?p=taxdetails&id=13551 on 2014-10-31 These hydrozoans always have a polyp stage. Their hydranths grow either solitary or in colonies. There is no firm

perisarc Hydrozoa (hydrozoans; ) are a taxonomic class of individually very small, predatory animals, some solitary and some colonial, most of which inhabit saline water. The colonies of the colonial species can be large, and in some cases the specialized ...

around the polyp body. The

medusa In Greek mythology, Medusa (; Ancient Greek: Μέδουσα "guardian, protectress"), also called Gorgo, was one of the three monstrous Gorgons, generally described as winged human females with living venomous snakes in place of hair. Those ...

e, or

jellyfish Jellyfish and sea jellies are the informal common names given to the medusa-phase of certain gelatinous members of the subphylum Medusozoa, a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals with umbre ...

, are solitary animals, with tentacles arising from the bell margin, lacking statocysts but possessing radial canals. Their

gonad A gonad, sex gland, or reproductive gland is a mixed gland that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gonad, the testicle, produces sp ...

s are on the manubrium ("handle").Bouillon, J.; Gravili, C.; Pagès, F.; Gili, J.-M.; Boero, F. (2006). An introduction to Hydrozoa. Mémoires du Muséum national d'Histoire naturelle, 194. Muséum national d'Histoire naturelle: Paris, France. . 591pp. + 1 cd-rom Except in

Eudendriidae Eudendriidae is a taxonomic family of hydroids (Hydrozoa). The family contains around 85 species. Genera *''Eudendrium ''Eudendrium'' is a large genus of hydroids (Hydrozoa), one of two in the family Eudendriidae. These animals are marine c ...

and

Laingiidae Magapiidae is a family of cnidarians belonging to the order Anthoathecata Anthoathecata, or the athecate hydroids, are an order of hydrozoans belonging to the phylum Cnidaria. A profusion of alternate scientific names exists for this long-know ...

, prey can be captured by discharging harpoon-like structures ( desmonemes) from chambers ( cnidae) in specialized cells (

nematocyst A cnidocyte (also known as a cnidoblast or nematocyte) is an explosive cell containing one large secretory organelle called a cnidocyst (also known as a cnida () or nematocyst) that can deliver a sting to other organisms. The presence of this ce ...

s) on the tentacles. In hydrozoans, these are nearly always adhesive and entrapping, rather than puncturing and poisoned as in other jellys.

Systematics

The close relationship of the orders Anthoathecata and Leptomedusae has been long known, but formerly it was also believed that these two were close to the order Limnomedusae. However, their closest relatives are the highly advanced Siphonophorae, whereas the Limnomedusae are a rather primitive group, and not very closely related to these three

Leptolinae Hydroidolina is a subclass of Hydrozoa and makes up 90% of the class. Controversy surrounds who the sister groups of Hydroidolina are, but research has shown that three orders remain consistent as direct relatives: Siphonophorae, Anthoathecata, ...

, and might instead belong to the subclass Trachylinae. Some uncertainty existed regarding the taxonomy of the order Anthoathecata. The most simple scheme, used until recently by most authors since it was proposed in 1913, divided the order into a smaller suborder (

Filifera Filifera is a suborder of hydrozoans in the order Anthoathecata. They are found in marine, brackish and freshwater habitats. Characteristics Members of this suborder are characterised by the filiform tentacles of the polyps which do not termin ...

) and a second larger one ( Capitata), but several unusual Anthoathecatae did not fit into this arrangement, and a considerable number did so awkwardly. The Porpitidae, for example, are a highly aberrant group, and were at one time even considered a separate order "Chondrophora". However, they are currently considered to be derived from Zancleida. In the early 21st century, the well-known '' Hydra'' and its relatives – and most of the supposed filiferan infraorders Tubulariida and Moerisiida – were determined to be a very ancient lineage, recognized as suborder

Aplanulata Aplanulata is a suborder of Hydrozoa, a class of marine and freshwater invertebrates belonging to the phylum Cnidaria. The group have lost its planula larval stage, and the only remnants of the medusa stage is when they functions as gonophores ...

. Although not all Anthoathecatae have been firmly placed in the

phylogeny A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological s ...

, most are fairly certainly assigned at least to one of the major subdivisions. As a notable exception, a

prehistoric Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The us ...

family, the Heterastridiidae, is still highly disputed regarding its relationships to the extant taxa, as are a small number of very aberrant and/or little-known species such as the aptly named '' Saccohydra problematica''. The family Clathrozoellidae is placed with the Filifera here; in others it is placed in the Leptomedusae and sometimes even synonymized with their family

Clathrozoidae Clathrozoidae is a family of cnidarians belonging to the order Leptomedusae. Genera: * ''Clathrozoon'' Spencer, 1891 * ''Pseudoclathrozoon'' Hirohito, 1967 References

Leptothecata Cnidarian families {{Leptothecata-stub ...

. By contrast, the supposed filiferan genus ''Anthohydra'' is in fact the leptomedusan '' Eugymnanthea''; similarly, "'' Gammaria''" is also a leptomedusan and properly spelled '' Grammaria''. The supposed athecate family Monobrachiidae is apparently a close relative of the Olindiasidae, and belongs in the Limnomedusae. Halammohydridae and Otohydridae, sometimes placed here, appear to be trachyline hydrozoans of the order

Actinulidae Actinulida are an order of hydrozoans in the subclass Trachylinae Trachylinae (also Trachylina, Trachylinida, etc.) is a subclass of hydrozoans. It is placed at order rank in many older classifications, and limited to contain the Narcomedusa ...

Infraorders and families

Basal and ''

incertae sedis ' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertain ...

'' Anthoathecata * Genus '' Bibrachium'' Stechow, 1919 * Genus ''" Microstoma"'' Lesson, 1830 (''

nomen dubium In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium'' it may be impossible to determine whether a s ...

; non'' G.Cuvier, 1816:

preoccupied The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linnae ...

) * Genus '' Saccohydra'' Billiard, 1914 * †Family Heterastridiidae (

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

) Suborder

Collins, Winkelman, Hadrys & Schierwater, 2005 * Family Acaulidae Fraser, 1924 (formerly in Tubulariida) * Family Boeromedusidae Bouillon, 1995 (formerly in Moerisiida) * Family Boreohydridae Westblad, 1947 (formerly in Tubulariida) * Family Myriothelidae Hincks, 1868 (including Candelabridae, Symplectaneidae; formerly in Tubulariida) * Family Corymorphidae Allman, 1872 (including Amalthaeidae, Branchiocerianthidae, Euphysidae, Hypolytidae , Monocaulidae, Paragotoeidae, Steenstrupiini, Trichorhizini; formerly in Tubulariida) * Family Hydridae Dana, 1846 (formerly in Moerisiida) * Family Margelopsidae Uchida, 1927 (including Pelagohydridae; formerly in Tubulariida) * Family Paracorynidae Picard, 1957 (formerly in Tubulariida) * Family Protohydridae Allman, 1888 (formerly in Moerisiida) * Family Tubulariidae Suborder

Kühn, 1913 Basal or ''incertae sedis'' * Genus '' Brinckmannia'' Schuchert & Reiswig, 2006 * Genus '' Favonia'' Péron & Lesueur, 1810 (''

'') * Genus '' Kinetocodium'' Kramp, 1921 (Margelina: Hydractiniidae?) * Genus '' Lymnorea'' Péron & Lesueur, 1810 (= ''Limnorea; nomen dubium'') * Family Axoporidae Boschma, 1951 (

) * Family Bythotiaridae Maas, 1905 (including Calycopsidae; Pandeida?) * Family Clathrozoellidae Peña Cantero, Vervoort & Watson, 2003 (tentatively placed here) * Family Cordylophoridae von Lendenfeld, 1885 * Family Jeanbouilloniidae Pagès, Flood & Youngbluth, 2006 * Family Oceaniidae (Margelina?) * Family Tubiclavoididae Moura, Cunha & Schuchert, 2007 (Pandeida?) Infraorder Margelina Haeckel, 1879 (disputed) * Family Australomedusidae Russell, 1971 (including Platystomidae) * Family Balellidae Stechow, 1922 * Family

Bougainvilliidae Bougainvilliidae is a family of marine hydroids in the class Hydrozoa. Members of the family are found worldwide. There are sixteen accepted genera and about ninety-three species. Description Hydroids in this family can be solitary or colonial. ...

* Family Cytaeididae L.Agassiz, 1862 * Family Eucodoniidae Schuchert, 1996 * Family Hydractiniidae * Family

Ptilocodiidae Ptilocodiidae is a family of hydrozoans in the order Anthoathecata Anthoathecata, or the athecate hydroids, are an order of hydrozoans belonging to the phylum Cnidaria. A profusion of alternate scientific names exists for this long-known, he ...

Coward, 1909 * Family

Rathkeidae Rathkeidae is a family of cnidarians belonging to the order Anthoathecata Anthoathecata, or the athecate hydroids, are an order of hydrozoans belonging to the phylum Cnidaria. A profusion of alternate scientific names exists for this long-know ...

Russell, 1953 * Family

Rhysiidae ''Rhysia'' is a genus of cnidaria Cnidaria () is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in freshwater and marine environments, predominantly the latter. Their distinguishing feature is c ...

Hickson & Gravely, 1907; (tentatively placed here) * Family Stylasteridae (tentatively placed here) * Family

Trichydridae ''Trichydra'' is a monotypic genus of cnidaria Cnidaria () is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in freshwater and marine environments, predominantly the latter. Their distinguishing ...

Hincks, 1868 Infraorder Pandeida (disputed) * Family

* Family

Magapiidae Magapiidae is a family of cnidarians belonging to the order Anthoathecata Anthoathecata, or the athecate hydroids, are an order of hydrozoans belonging to the phylum Cnidaria. A profusion of alternate scientific names exists for this long-know ...

Schuchert & Bouillon, 2009 (formerly Laingiidae; tentatively placed here) * Family Niobiidae Petersen, 1979 * Family

Pandeidae Pandeidae is a family of hydroids in the class Hydrozoa. Like other jellyfish there is usually a mature medusa form which is pelagic and reproduces sexually and a hydroid or polyp form which is often benthic and reproduces asexually by budding ...

* Family

Proboscidactylidae Proboscidactylidae is a family of cnidarians belonging to the order Anthoathecata Anthoathecata, or the athecate hydroids, are an order of hydrozoans belonging to the phylum Cnidaria. A profusion of alternate scientific names exists for this l ...

Hand & Hendrickson, 1950 * Family

Protiaridae Protiaridae is a family of cnidarians belonging to the order Anthoathecata Anthoathecata, or the athecate hydroids, are an order of hydrozoans belonging to the phylum Cnidaria. A profusion of alternate scientific names exists for this long-kno ...

Haeckel, 1879 * Family Heterotentaculidae Schuchert, 2010 (formerly Russelliidae; tentatively placed here) Suborder Capitata Kühn, 1913 Basal or ''incertae sedis'' * Genus '' Cnidocodon'' Bouillon, 1978 (including ''Ramus'') * Genus '' Ctenaria'' (Zancleida: Zancleidae?) * Genus '' Oonautes'' Damas, 1937 (Zancleida: Zancleidae?) * Genus '' Paulinum'' Brinckmann-Voss & Arai, 1998 * Genus '' Plotocnide'' Wagner, 1885 (including ''Plankayon'') * Genus '' Propachycordyle'' Thiel, 1931 * Genus '' Pteronema'' Haeckel, 1879 * Genus '' Rhabdoon'' Keferstein & Ehlers, 1861 (including ''Pararhysomedusa'', ''Rhysomedusa'', ''Yakovia'') * Genus '' Tetraralphia'' Pagès & Bouillon, 1997 Infraorder Moerisiida Poche, 1914 (disputed) * Family Halimedusidae Arai & Brinckmann-Voss, 1980 (tentatively placed here) * Family Moerisiidae Poche, 1914 Infraorder Sphaerocorynida Petersen, 1990 (disputed) * Family Hydrocorynidae Rees, 1957 * Family Sphaerocorynidae Prévot, 1959 * Family Zancleopsidae Bouillon, 1978 Infraorder N.N.New name is required for the remaining Tubulariida, because Tubulariidae has been moved to Aplanulata. (disputed) * Family Cladonematidae * Family

Corynidae Corynidae is a family of hydrozoans in the order Anthomedusae Anthoathecata, or the athecate hydroids, are an order of hydrozoans belonging to the phylum Cnidaria. A profusion of alternate scientific names exists for this long-known, heavily ...

* Family Euphysidae * Family Pennariidae McCrady, 1859 (including Halocordylidae) * Family Solanderiidae * Family Tricyclusidae Kramp, 1949 Infraorder Zancleida Russell, 1953 (disputed) * Family Asyncorynidae Kramp, 1949 * Family Cladocorynidae Allman, 1872 * Family Milleporidae Fleming, 1828 (= Milleporadae) * Family Porpitidae * Family Pseudosolanderiidae Bouillon & Gravier-Bonnet, 1988 * Family Rosalindidae Bouillon, 1985 * Family Teissieridae Bouillon, 1978 * Family Zancleidae Russell, 1953 (including Corynipteridae, Halocorynidae, Orthocorynidae)

References

Bibliography * Buecher, E., Goy, J. & Gibbons, M.J. 2005. Hydromedusae of the Agulhas Current. ''

African Invertebrates ''African Invertebrates'' is a peer-reviewed open access scientific journal that covers the taxonomy, systematics, biogeography, ecology, conservation, and palaeontology of Afrotropical invertebrates, whether terrestrial, freshwater, or ma ...

'' 46: 27-6

External links

North East Atlantic TaxaFamily, genus and species list
{{Taxonbar, from1=Q14556976, from2=Q2344380 Hydroidolina Cnidarian orders