Hymenostome

Hymenostome

Taxobox | color = khaki
name = Hymenostomes
domain = Eukaryota
unranked_phylum = Alveolata
phylum = Ciliophora
classis = Oligohymenophorea
ordo = Hymenostomatida
ordo_authority = Delage & Hérouard 1896
subdivision_ranks = Typical families
subdivision = Suborder Tetrahymenina
Curimostomatidae
Tetrahymenidae
Turaniellidae
Glaucomidae
Suborder Ophryoglenina
Ichthyopthiriidae
Ophryoglenidae
The hymenostomes are an order of ciliate protozoa. Most are free-living in freshwater, such as the commonly studied genus "Tetrahymena", but some are parasitic on fish or aquatic invertebrates. Among these is the important species "Ichthyopthirius multifiliis", a common cause of death in aquaria and fish farms.

The hymenostomes are fairly typical members of the Oligohymenophorea. Their body cilia are mostly uniform, sometimes with a few long caudal cilia, and arise from monokinetids or from dikinetids at the anterior. The oral cilia are in general distincly tetrahymenal, with three membranelles and a paroral membrane, which corresponds only to the middle segment of the tripartite membranes found in certain scuticociliates. Mouth formation during cell division usually begins next to a postoral kinety.

The hymenostomes were first defined by Delage & Hérouard in 1896. Initially the scuticociliates and peniculids were included, then later treated as separate orders of a subclass Hymenostomatia, to which the astomes are sometimes added. More recently each of these groups tends to be treated as a separate subclass.


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  • hymenostome — ▪ protozoan       any member of the evenly ciliated protozoan order Hymenostomatida. Included in this order are the genus Paramecium, often used in laboratory studies, and the even more widely studied genus Tetrahymena, which can be easily… …   Universalium

  • Peniculid — Taxobox | color = #FA7B62 name = Peniculids image caption = Paramecium aurelia domain = Eukaryota regnum = Chromalveolata superphylum = Alveolata phylum = Ciliophora classis = Oligohymenophorea ordo = Peniculida ordo authority = Fauré Fremiet in… …   Wikipedia

  • υμενόστομα — τα, Ν ζωολ. τάξη βλεφαριδοφόρων πρωτοζώων. [ΕΤΥΜΟΛ. Αντιδάνεια λ., πρβλ. αγγλ. hymenostome (< υμένας + στόμα)] …   Dictionary of Greek

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