medusa dalam siklus hidupnya. Genus ini berada dalam filum Cnidaria, yang semuanya akuatik dan terutama hidup di laut yang strukturnya relatif sederhana. Transcript of Filum Cnidaria (Coelenterata). Nama Anggota: 1. Fadhil Nurrohman (06) 2. Fika Pebianti (07) 3. Lilastika Cattri (13) 4. Hydrozoa adalah kelas dari anggota hewan tak bertulang belakang yang termasuk dalam filum Cnidaria. Sebagian besar hewan Hydrozoa hidup di laut dan.

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Hydrozoans are related to jellyfish and corals and belong to the phylum Cnidaria.

As far as can be told from the molecular and morphological data at hand, the Siphonophora for example were just highly cnidarka “hydroids,” whereas the Limnomedusae —presumed to be a “hydroid” suborder —were simply very primitive hydrozoans and not cnidara related to the other “hydroids. A few genera within this class live in fresh water. ITIS uses the same system, but unlike here, does not use the oldest available names for many groups.

In others, one polyp may develop as a large float, from which the other polyps hang down, allowing the colony to drift in open water instead of being anchored to a solid surface. Some examples of hydrozoans are the freshwater jelly Craspedacusta sowerbyifreshwater polyps HydraObeliaPortuguese man o’ war Physalia physalischondrophores Porpitidae” air fern ” Sertularia argentea cnidqria, and pink-hearted hydroids Tubularia.

Although most hydrozoans have a medusoid stage, this is not always free-living, and in many species, exists solely as a sexually reproducing bud on the surface of the hydroid colony. Hydroid colonies are usually dioeciouswhich means they have separate sexes—all the polyps in each colony are either male or female, but not usually both sexes in the same colony. Views Read Edit View history. Several approaches for expressing their interrelationships were proposed and heavily contested since the late 19th century, but in more recent times a consensus seems to be emerging.


Hydrozoa – Wikiwand

Unlike some other cnidarian groups, the lining of the central cavity lacks stinging nematocystswhich are found only on the tentacles and outer surface. Where the hydrocaulus runs along the substrate, it form a horizontal root-like stolon that anchors the colony to the bottom. In some, defensive polyps are found, armed with large numbers of stinging cells. Zygotes become free-swimming planula larvae or actinula larvae that either settle on a suitable substrate in the case of planulaeor swim and develop into another medusa or polyp directly actinulae.

Hydrozoa – Wikipedia

Numerous sense organs are closely associated with the nerve rings. By using this site, you agree to the Terms of Use and Privacy Policy. All colonial hydrozoans also include some polyps specialized for reproduction. Most hydrozoan species include both a polypoid and a medusoid stage in their lifecycles, although a number of them have only one or the other.

Hydrozoan systematics are highly complex. Wikispecies has information related to Hydrozoa. A tube-like structure hangs down from the centre of the umbrella, and includes the mouth at its tip. cnixaria

Historically, the hydrozoans were divided into a number of ordersaccording to their mode of growth and reproduction. Two nerve rings lie close to the margin of the bell, and send fibres into the muscles and tentacles.

The body consists of a dome-like umbrella ringed by tentacles. Mostly these are simple sensory nerve endings, but they also include statocysts and primitive light-sensitive ocelli. These have a more or less cylindrical body with a terminal mouth on a raised protuberance called the hypostomesurrounded by a number of tentacles. For example, Hydra has no medusoid stage, while Liriope lacks the hydroid stage. The mouth leads into a central stomach cavity. The hollow cavity in the middle of the polyp extends into the associated hydrocaulus, so that all the individuals of the colony are intimately connected.


Though they are often found in seemingly authoritative Internet sources and databases, they do not agree with the available data. In any given colony, the majority of polyps are specialized for feeding.

The medusae of hydrozoans are smaller than those of typical jellyfish, ranging from 0. The colonies of the colonial species can be large, and in some cases the specialized individual animals cannot survive outside the colony. Wikimedia Commons has media related to Hydrozoa. The nervous system is unusually advanced for cnidarians.

Most famous among these was probably the assemblage called ” Hydroida “, but this group is apparently paraphyleticunited by plesiomorphic ancestral traits. In any case, according to this classification, the hydrozoans can be subdivided as follows, with taxon names emended to end in “-ae”: The polyp contains a central cavity, in which initial digestion takes place.

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It was traditionally placed in its own classPolypodiozoa, and this view is often seen to reflect the uncertainties surrounding this highly distinct animal.

In hydrozoan species with both polyp and medusa generations, the medusa stage is the sexually reproductive phase. In other projects Wikimedia Commons Wikispecies.

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