Keratella cochlearis

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title: "Keratella cochlearis" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["brachionidae", "taxa-named-by-philip-henry-gosse", "animals-described-in-1851"] description: "Species of rotifer" topic_path: "general/brachionidae" source: "https://en.wikipedia.org/wiki/Keratella_cochlearis" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Species of rotifer ::

| image = KellicottiaAndKeratella.JPG | image_caption = Kellicottia longispina and Keratella cochlearis | genus = Keratella | species = cochlearis | authority = (Gosse, 1851)

Keratella cochlearis is a rotifer. The planktonic animal occurs worldwide in freshwater and marine habitats.

Description

Keratella cochlearis has an oval lorica, a shell-like protective outer cuticle. At the anterior end are three pairs of spines. The central pair curve towards the ventral surface, the next pair diverge slightly and the outer pair converge. There is a single red eye There is also a central funnel-shaped mouth and on either side of this are rings of cilia which twirl and help waft food particles into the mouth. They are also used for locomotion. There are two forms of this rotifer; some individuals have a long spine at the posterior end and others do not. Neither form has a foot. ::figure[src="https://upload.wikimedia.org/wikipedia/commons/e/ec/Fish01.png" caption="Lorica of the [[Rotifer]] ''Keratella cochlearis'', [[Scanning electron microscope]] photo." alt=""] ::

Distribution

Keratella cochlearis is found worldwide in marine, brackish and freshwater habitats. Any body of standing water is likely to contain rotifers and Keratella cochlearis is probably the most common and widespread species in the world.

Life cycle

Keratella cochlearis is dioecious, with female specimens being larger than males. Typically, reproduction in this species is by parthenogenesis. In this process, the female rotifer produces an unfertilised egg with a full set of chromosomes. This is carried around by the mother and hatches into a miniature adult. Whether the offspring has a posterior spine or not seems to depend on the number of predators in the body of water where the rotifer lives. If predation rates are high, spined "typica" forms are produced, but if low, spineless forms known as "tecta" develop. Tecta females can produce typica offspring and vice versa.

Periodically sexual reproduction takes place. It is not known why this occurs at some times and not others. The female undergoes meiosis and produces eggs with half the usual number of chromosomes. Some of these develop into male rotifers. Each of these is able to inseminate another of these eggs to restore the full complement of chromosomes in the offspring.

References

References

1. Segers, Hendrik. (2012). "''Keratella cochlearis'' (Gosse, 1851)".
2. H. Streble, D. Krauter: ''Das Leben im Wassertropfen. Mikroflora und Mikrofauna des Süßwassers''. Kosmos Verlag, Stuttgart 2006.
3. Pontin, Rosalind M. (1978). "A Key to British Freshwater Planktonic Rotifera". Freshwater Biological Association.
4. "''Keratella cochlearis''". Central Michigan University.
5. "''Keratella cochlearis'' (Gosse 1851)". LifeDesks: Marine Rotifera.
6. Barnes, Robert D.. (1982). "Invertebrate Zoology". Holt-Saunders International.

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