Orthonectida

Orthonectids
Two altered changeable Orthonectids
Scientific classification
Kingdom:	Animalia
(unranked):	Mesozoa
Phylum:	Orthonectida Giard, 1880
Families
Pelmatosphaeridae Rhopaluridae

Orthonectida (pronounced /ˌɔrθɵˈnɛktɪdə/) is a baby phylum of poorly-known parasites of abyssal invertebrates¹ that are a part of the simplest of multi-cellular organisms. Members of this phylum are accepted as orthonectids.

Contents 1 Biology 2 Classification 3 External links 4 References

Biology

The adults are diminutive wormlike animals, consisting of a alone band of ciliated alien beef surrounding a accumulation of sex cells. They bathe advisedly aural the bodies of their hosts, which cover flatworms, polychaete worms, bivalve molluscs, and echinoderms. They are dioecious, with abstracted macho and changeable individuals.²

When they are accessible to reproduce, the adults are appear from the host, and agent from the males penetrates the bodies of the females to accomplish centralized fertilisation. The consistent zygote develops into a ciliated larva that escapes from the mother to seek out new hosts. Once it finds a host, the larva loses its cilia and develops into a syncitial plasmodium larva. This, in turn, break up into abundant alone beef that become the next bearing of adults.²

Classification

The phylum consists of about 20 accepted species, of which Rhopalura ophiocomae is the best-known.¹ The phylum is not disconnected into classes or orders, and contains just two families.

Originally declared in 1880 as a class,³ and sometimes characterized as an adjustment of the phylum Mesozoa, contempo abstraction shows that orthonectids are absolutely altered from the rhombozoans, the added accumulation in Mesozoa.¹

Known species:

Phylum Orthonectida

• Family Rhopaluridae
  • Ciliocincta akkeshiensis (Tajika, 1979) - Hokkaido, Japan; in flatworms (Turbellaria)
  • Ciliocincta julini (Caullery and Mesnil, 1899) - E North Atlantic, in polychaetes
  • Ciliocincta sabellariae (Kozloff, 1965) - San Juan Islands, WA (USA); in polychaete (Sabellaria cementarium)
  • Intoshia leptoplanae (Giard, 1877) - E North Atlantic, in flatworms (Leptoplana)
  • Intoshia linei (Giard, 1877) - E North Atlantic, in nemertines (Lineus) = Rhopalura linei
  • Intoshia major (Shtein, 1953) - Arctic Ocean; in gastropods (Lepeta, Natica, Solariella) = Rhopalura major
  • Intoshia paraphanostomae (Westblad, 1942) - E North Atlantic, in flatworms (Acoela)
  • Rhopalura elongata (Shtein, 1953) - Arctic Ocean, in bivalves (Astarte)
  • Rhopalura gigas (Giard, 1877)
  • Rhopalura granosa (Atkins, 1933) - E North Atlantic, in bivalves (Pododesmus)
  • Rhopalura intoshi (Metchnikoff) - Mediterranean, in nemertines
  • Rhopalura litoralis (Shtein, 1954) - Arctic Ocean, in gastropods (Lepeta, Natica, Solariella)
  • Rhopalura metschnikowi (Caullery and Mesnil, 1901) - E North Atlantic, in polychaetes and nemertines
  • Rhopalura murmanica (Shtein, 1953) - Arctic Ocean, in gastropods (Rissoa, Columbella)
  • Rhopalura ophiocomae (Giard, 1877) - E North Atlantic, in ophiuroids (usually Amphipholis)
  • Rhopalura pelseeneri (Caullery and Mesnil, 1901) - E North Atlantic, polychaetes and nemertines
  • Rhopalura philinae (Lang, 1951) - E North Atlantic, in gastropods
  • Rhopalura pterocirri (de Saint-Joseph, 1896) E North Atlantic, in polychaetes
  • Rhopalura variabili (Alexandrov and Sljusarev, 1992) - Arctic Ocean, in flatworms (Macrorhynchus)
  • Stoecharthrum giardi (Caullery and Mesnil, 1899) - E North Atlantic, in polychaetes
  • Stoecharthrum monnati (Kozloff, 1993) - E North Atlantic, in molluscs

• Family Pelmatosphaeridae
  • Pelmatosphaera polycirri (Caullery and Mesnil, 1904) - E North Atlantic, in polychaetes and nemertines

External links

Wikispecies has advice accompanying to: Orthonectida

References

v • d • e Extant phyla of commonwealth Animalia by subkingdom Parazoa Porifera (Calcarea, Demospongiae, Hexactinellida) · Placozoa (Trichoplax) Mesozoa Orthonectida · Rhombozoa Eumetazoa Radiata Ctenophora · Cnidaria (Anthozoa, Hydrozoa, Scyphozoa, Cubozoa, Staurozoa, Myxozoa) Bilateria Protostomia Ecdysozoa Cycloneuralia: Scalidophora (Kinorhyncha, Loricifera, Priapulida) · Nematoida (Nematoda, Nematomorpha) Panarthropoda: Onychophora · Tardigrada · Arthropoda Spiralia Platyzoa Platyhelminthes · Gastrotricha Gnathifera: Rotifera · Acanthocephala · Gnathostomulida · Micrognathozoa · Cycliophora Lophotrochozoa Trochozoa (Sipuncula, Nemertea, Mollusca, Annelida) Lophophorata (Bryozoa, Entoprocta, Phoronida, Brachiopoda) Deuterostomia Ambulacraria Hemichordata · Echinodermata · Xenoturbellida Chordata Craniata (Vertebrata, Myxini) · Cephalochordata · Tunicata Basal/disputed Acoelomorpha (Acoela, Nemertodermatida) · Chaetognatha