Scientific classification e
Kingdom: Animalia
Phylum: Ctenophora
Class: Nuda
Order: Beroida
Family: Beroidae
Chun, 1879
  • comb jellies. As their name implies, they are distinguished from other comb jellies by the complete absence of tentacles. Nudans are found in all the world's oceans and seas, where they swim freely in the plankton.



    Nuda often reach a length of up to 30 centimetres (12 in), with Neis cordigera often referred to[by whom?] as the largest type. The sack-like body of the Beröe species is easily compressed perpendicular to the plane of the gap, while Neis is flattening by training two "wing" even more pronounced[vague].

    Like other comb jellies, the body wall of nudans consists of an outer epidermis and an inner gastrodermis, separated by a jelly-like mesoglea. The mesoglea has pigments that give many nudan species a slightly pink color; for example, Neis cordigera is strong orange-red.

    Mouth opening and muscles

    As prey as a whole with his mouth devoured, has this and the subsequent jump gap including one in comparison to other ctenophores a large diameter. In order for swimming, and especially in the pursuit of prey in the water to reduce resistance, it can seal firmly by a zip-like mechanism, so that the ctenophore attains a streamlined front. This will close the opposite sides of the gap, the "lips", not only brought in close contact, but by temporarily trained cell-cell connections closely interlinked. The whole ctenophore own nerve network is within the "lip" of a Nuda of about 40 nerve cell Fort records (Neurit), this bundle of compacted.

    The palate is caused by the interplay of three different types of muscle open and closed: In the mesoglea lost both ring around the longitudinal axis of the animal and arranged radial, radially outwards from the inside running muscle fibers; they interact with longitudinal, so längsseitig oriented fibers, which the epidermis.

    Nudans have only smooth muscle fibres.


    Directly inside the mouth opening can be found in the lining of the gap characteristic finger-like excesses, Macrocilia. In this first 1844 of JGF Will described and 1965 by George Adrian Horridge with her today named structures are conical shaped by a common plasma membrane surrounded bundles of two to three scourges (cilia), which, as in the comb plates of ribs to a functional unit connected. The individual, between 35 and 60 micrometres in diameter long and 5 to 10 micrometres thick cilia together in a hexagonal cross-sectional structure, and are perpendicular to the direction of common connected by crossbars, a separate membrane, which they divide their neighbor scourges would have it they are not. Each cilium shows the typical eukaryote construction of nine external and two internal microtubules.

    The scourge cells, in which the cilia from individual basal bodies arise, to the Schlundauskleidung by an average of thirty degrees to mundabgewandten side and, stacked on top like roof tiles. Thus, the macrocilia always point in the direction of the interior of the throat. This is where is the effective strike, which is prey parts in synchronized waves like a conveyor belt transported in the stomach and the throat muscles promoted this process.

    Macrocilia run in a three toothed top of this is stiff enough to the soft outer wall to rip even larger prey like other ctenophores; proteolytic enzyme penetrate into the resulting wounds, make the victim then quickly escape.

    Macrocilia also function as teeth, and can be used in the same way as the tentacles of Tentaculata.

    Affairs channel system

    From the main drag from stomach like all ctenophore channels in all regions of the body. Each rib will comb through its own meridional canal furnished directly below this location. He owns at the Nuda species many fine ramified excesses, some of which deal with the gap unite, but others end up blind. To that end mouth running the meridional canal in a circle around the mouth lying ring channel.

    Statocyste and polepieces

    As with all ctenophores, is at the mundabgewandten side Gleichwichtsorgan, statocyst, including the clock for the ribs arranged on the ridge platelets determine. The shock pulse, unlike in the Lobata, is not through the ridge between platelets oblique scourge forwarded tapes, but the fact that the individual comb platelets in turn fall, like dominoes, the subsequent platelet influence.

    Immediately below the statocyst is an inlet lined with sensory cells, which contains epithelial tissue has to mouth out in two opposite narrow bands scourge continues, in the throat level of ctenophore run and as a polepieces. You call a strike by its water flow on the statocyst shows and are used by the Nuda-Arten at its border with finger excesses, the papillae occupied whose function is still unclear, but probably also sensory perception.

    Unlike other groups of ctenophores put them to continue their movement almost exclusively comb ribs.


    Nudans feed on free swimming animals with soft bodies, primarily from other ctenophores, certainly larger than they themselves can be. They actively hunt for prey, which they usually devour whole. Some species use their macrocilia as teeth to take smaller chunks from the prey.

    As invasive species

    Beroe ovata on the Black Sea Coast

    In the late 1980s the ctenophore species Mnemiopsis leidyi was introduced into the Black Sea, probably through ballast water, which led to the collapse of the local anchovy population. In 1997 another ctenophore species arrived--Beroe ovata, a predator of Mnemiopsis leidyi. The Beroe population underwent an initial explosion, until the numbers of both ctenophores stabilized. Nevertheless, both Mnemiopsis leidyi and Beroe ovata remain today in the Black Sea. The same phenomenon is occurring at the beginning of the 21st century in the Caspian Sea.


    All species reproduce sexually, and have both female and male gonad. Although no detailed figures are available, it is assumed that self-fertilization is the exception among nudans.

    The fertilized eggs hatch into miniature versions of the adult animal, rather than distinct larval forms. They already lack the tentacles and Tentakelscheiden, otherwise they are similar to the Cydippea stadum.

    History of the species

    There are no known fossil nudans, so the phylogenetic evolution of the group from the comparison with other modern representatives of Rippenquallen tapped to be. In the traditional system, the Nuda form a class distinct from the Tentaculata, which all have at least rudimentary tentacles. This division, after provisional results of morphological and molecular studies, however, probably does not reflect the actual relationships within the ctenophores.

    Although the scheme is still in the river and does not have an independent assessment of the available evidence, seems to be a family from the order Cydippida, Haeckelidae, in the closer relationship of Nuda species to belong neither Cydippida still Tentaculata would therefore cladistic taxa included not all offspring of their joint Vorfahrens and would therefore is not recognised as a valid taxon in modern schemes.

    The monophyly of Nuda itself, is however widely accepted, due to the complete lack of tentacles, and the presence of macrocilia as a common secondary feature, or synapomorphy.


    There are approximately 25 species, grouped into two genera in the single family Beroidae. The family and order were named in 1825 or 1829 by the German naturalist Johann Friedrich Eschscholtz.

    • The genus Beröe includes nearly all types of class and is distributed worldwide. One of the best known is reflected in the North spread Melonenqualle (Beröe gracilis). In Beröe species is mundabgewandte (aboral) side down.
    • The genus Neis is monotypical, containing only one species, Neis cordigera(Lesson 1824), and is found only in the waters around Australia. In this type are located on the aboralen page two bogenartige progress rates, so that the middle intermediate aborale Sinnespol unlike the Beroiden not at the extreme end of the body is located (Note Artname cordigera: heart). The bogenartigen Fort sentences extend along the flanks of the animal and are Längsverlauf divided so that the impression of two sides "double wings". At the edges of these four "wings" is one rib band. The remaining four ribs on the lost tapes (relative to the "side wings") "upper" and "lower" body half. The ctenophore typical eight ribs number of bands is obtained, even if the tapes because of the particular body shape into two different groups - long training.


    • G. I. Matsumoto, GR Harbison:In situ observations of foraging, feeding, and escape behavior in three orders of oceanic ctenophores: Lobata, Cestida, and Beroida.Marine Biology. '117 ', 1993, p. 279th
    • S. Tamm, SL Tamm:A giant nerve net with multieffector synapses underlying epithelial adhesive strips in the mouth of Beroe.In the Journal of Neurocytology. '24 ', 1995, p. 711st
    • S. Tamm, SL Tamm:Dynamic control of cell-cell-adhesion and membrane-associated actin during food-induced mouth opening in Beroe.In the Journal of Cell Science. '106 ', 1993, p. 355

    Wikimedia Foundation. 2010.

    Look at other dictionaries:

    • Nuda — Eine Art der Beroe Systematik Reich: Tiere (Animalia) Unterreich: Vielzellige Tiere (Meta …   Deutsch Wikipedia

    • nuda — I {{/stl 13}}{{stl 8}}rz. ż Ia, CMc. nudzie {{/stl 8}}{{stl 7}}1 uczucie przygnębienia wywołane brakiem lub jednostajnością wrażeń : {{/stl 7}}{{stl 10}}Straszna nuda. Niesamowite, okropne nudy. Męczy go nuda.2 {{/stl 10}}{{stl 7}} cecha tego, co …   Langenscheidt Polski wyjaśnień

    • nūda — ×nūdà (plg. l. nuda) sf. (4), nudà (4) Ldvn, Lš 1. J liūdesys, sielvartas: Taip mane ėda nūda, kai motina numirė Mlt. Pameskit bėdas kap nūdą kokią Pns. Nuo nūdos jos baltiniuos ir galvoj atsirado ydo A.Vien. 2. kas grasu, įkyru, bodu: Tikra… …   Dictionary of the Lithuanian Language

    • Nuda —   Nuda …   Wikipedia Español

    • nuda — 1 ×nudà (plg. l. nuda) sf. (4) niežtėjimas, kylantis iš nešvarumo ar gyvio; susas: Nudà tokia užpuolė: niežti visą kūną, rankom kai pabrauki, rievės tokios lupasi Ss. Eik, nusiprausk pirtin, ba nudà užpuls Lš. Mane nuda apsėdo Vdšk. Apsėstas… …   Dictionary of the Lithuanian Language

    • Nuda — Beroe sp …   Wikipédia en Français

    • nuda — ż IV, CMs. nudzie; lm D. nudadów 1. «niemiły stan, niemiłe uczucie spowodowane zwykle bezczynnością, brakiem interesującego zajęcia, brakiem wrażeń, monotonią życia; cecha rzeczy wywołującej taki stan (także w lm w tym samym znaczeniu)»… …   Słownik języka polskiego

    • nuda — 2 ×nudà (plg. l. nuda) scom. (2) Grv, Skrd nepaslankus žmogus, tinginys, apsnūdėlis: Toks nudà tik už pilvą turėtų dirbti Vrb. Eik, eik, nudà, greičiau! Smn. Iš tavę baisi nudà, vaikeli Smn. Nudini, tai nudini, kap kokis nudà Srj. Tokio… …   Dictionary of the Lithuanian Language

    • nuda —   , nudum, nudus   L. bare.   1) Lemmas glabrous. Andropogon nudus, Arthraxon nudus, Avena nuda, Bathratherum nudum, Digitaria nuda, Hordeum nudum, Poa nuda, Pollinia nuda   2) rachilla joints glabrous. Microstegium nudum, Phragmites nudus   3)… …   Etymological dictionary of grasses

    • Nuda — noun ctenophores lacking tentacles; comprises one genus: beroe • Syn: ↑class Nuda • Hypernyms: ↑class • Member Holonyms: ↑Ctenophora, ↑phylum Ctenophora …   Useful english dictionary