Zancleidae

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Zancleidae
Zanclea implexa, portion of colony (from Allman, 1872).png
Zanclea implexa
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Cnidaria
Class: Hydrozoa
Order: Anthoathecata
Family: Zancleidae
Russell, 1953

Zancleidae is a family of cnidarians belonging to the order Anthoathecata. [1]

Contents

Genera: [1]

Defining characteristics

Zancleidae is a family of hydrozoans from the order Anthoathecata. Hydrozoans are a class from the phylum Cnidaria, which include jellyfish, sea anemones, and other invertebrates. Cnidarians are defined by their two distinct tissue layers and radial symmetry. These characteristics distinguish them from invertebrates of the clade bilateria, which possess bilateral symmetry in their adult or larval forms. Hydrozoans can be colonial or solitary organisms and are often very small on their own.  Zancleidae polyps are arranged in colonies and range from 700-750 um in their medusa stage. [2] Currently, there are three main genera described as, Zanclea Gegenbaur, Halocoryne Hadzi, and Zanclella Boero & Hewitt. Within these three genera, there are around 42 accepted species. [3] Zancleids have a complicated taxonomic history, and new species are discovered fairly often due to a better understanding of the range of variation between organisms of this family. [4]

Anatomy and morphology

Zancleidae are colonial organisms that live in symbiosis with other benthic invertebrates. [3] They are most commonly seen in association with cheilostomata bryozoa. [5] Other species display a preference toward different organisms, such as bivalves, corals, and algae. [3] Some scientists believe that they serve as protection for their choice host organism, but others argue that their relationship can be parasitic. [5] The colonies of zancleids are separated into small polyps, which arise from asexual reproduction. Most species only have monomorphic polyps, designed for protection and feeding, but some other species have both gastrozooids and dactylozooids, which specialize in different roles. [4] Zancleidae attaches to the surface of their host by a thin root-like structure called a hydrorhiza. These organisms are stolons and are often found embedded into the skeleton of whatever organism they prefer to live with. [3] The polyps have a white-ish clear coloring and appear orange in some parts. [4] Just like all cnidaria, their tentacles are lined with cnidophores, that house harpoon-like stinging cells called nematocysts. These tentacles are used as a defense for both themselves and their host. [3] All of the species experience polyp and medusa stages, which vary in length depending on the species and other external factors. [3] Gastrozooids are responsible for producing and releasing the medusa buds. [4] The medusae are spherical and sometimes appear greenish. These miniature jellyfish-like organisms can have either zero, two, or four tentacles depending on the species. [4] It is theorized that their number of tentacles can be tied to their relationship with their host organism. [3] During the medusa stage, the zancleids feed on small organisms in their proximity, and eggs are released into the water column. These eggs will then be fertilized and will help to facilitate the growth of new colonies. [4]

Ecological role

Gastrozooids specialize as the feeding mechanism within the zancleidae colonies. They are said to feed on the bryozoan lophophore and also zooplankton from the surrounding water. [5] The bryozoans, on the other hand, feed on phytoplankton, so there is no competition between the species. [4] In the medusa stage, the zancleids have been observed catching prey that they encountered by chance. The prey would then be immobilized by the tentacles and moved into the mouth cavity of the organism. [4] For colonies that prefer to live in association with corals, their presence in the community plays a role in the functionality of their surrounding ecosystem. [2]

Distribution

Zancleidae has a wide-ranging distribution and has been discovered in a number of different places in the world's oceans. Many studies focusing on these organisms examined ones living in the Maldives and the Red Sea, but they have also been identified in the Indian ocean and throughout the Pacific. [6] Since their distribution underwater is connected to that of their hosts, they are found primarily in benthic environments. Some are also said to only appear in conjunction with their host when that organism has grown to a certain size. In terms of distribution within the benthic environment, bryozoans, the most common host for zancleids, have been seen to express a preference for shaded habitats in the intertidal or infralittoral zones. [4]

Taxonomic history

The phylogenetic origins of zancleidae are fairly unclear due to the lack of research. Very few studies have focused on compiling the DNA sequences of the different species, and it has also been difficult for scientists to find viable, fertile colonies to conduct their research on. [3] These factors severely limit the amount of work that can be done in relation to the classification of these organisms. It is accepted though, that convergent evolution with their hosts has driven speciation among the zancleidae family. [3] Many of these species have seen a large reduction in their polyp and medusa stages over the years, which helps support the theories of speciation. [6] It is also clear that differing numbers of tentacles distinguish species from each other, along with the presence of dactylozooids within the colonies. [4] The preference of host organism is another defining characteristic that is used as a means for classification between species.

Related Research Articles

<span class="mw-page-title-main">Cnidaria</span> Aquatic animal phylum having cnydocytes

Cnidaria is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in freshwater and marine environments, including jellyfish, hydroids, sea anemone, corals and some of the smallest marine parasites. Their distinguishing features are a decentralized nervous system distributed throughout a gelatinous body and the presence of cnidocytes or cnidoblasts, specialized cells with ejectable flagella used mainly for envenomation and capturing prey. Their bodies consist of mesoglea, a non-living jelly-like substance, sandwiched between two layers of epithelium that are mostly one cell thick.

<span class="mw-page-title-main">Hydrozoa</span> Class of cnidarians

Hydrozoa is a taxonomic class of individually very small, predatory animals, some solitary and some colonial, most of which inhabit saline water. The colonies of the colonial species can be large, and in some cases the specialized individual animals cannot survive outside the colony. A few genera within this class live in freshwater habitats. Hydrozoans are related to jellyfish and corals and belong to the phylum Cnidaria.

<i>Obelia</i> Genus of hydrozoans

Obelia is a genus of hydrozoans, a class of mainly marine and some freshwater animal species that have both polyp and medusa stages in their life cycle. Hydrozoa belongs to the phylum Cnidaria, which are aquatic organisms that are relatively simple in structure with a diameter around 1mm. There are currently 120 known species, with more to be discovered. These species are grouped into three broad categories: O. bidentata, O. dichotoma, and O. geniculata. O. longissima was later accepted as a legitimate species, but taxonomy regarding the entire genus is debated over.

<i>Turritopsis dohrnii</i> Species of small, biologically immortal jellyfish

Turritopsis dohrnii, also known as the immortal jellyfish, is a species of small, biologically immortal jellyfish found worldwide in temperate to tropic waters. It is one of the few known cases of animals capable of reverting completely to a sexually immature, colonial stage after having reached sexual maturity as a solitary individual. Others include the jellyfish Laodicea undulata and species of the genus Aurelia.

<span class="mw-page-title-main">Anthoathecata</span> Order of hydrozoans which always have a polyp stage

Anthoathecata, or the athecate hydroids, are an order of hydrozoans belonging to the phylum Cnidaria. A profusion of alternate scientific names exists for this long-known, heavily discussed, and spectacular group. It has also been called Gymnoblastea and, Anthomedusa,Athecata, Hydromedusa, and Stylasterina. There are about 1,200 species worldwide.

<i>Chrysaora hysoscella</i> Species of jellyfish

Chrysaora hysoscella, the compass jellyfish, is a common species of jellyfish that inhabits coastal waters in temperate regions of the northeastern Atlantic Ocean, including the North Sea and Mediterranean Sea. In the past it was also recorded in the southeastern Atlantic, including South Africa, but this was caused by confusion with close relatives; C. africana, C. fulgida and an undescribed species tentatively referred to as "C. agulhensis".

<span class="mw-page-title-main">Hydroidolina</span> Subclass of hydrozoans

Hydroidolina is a subclass of Hydrozoa and makes up 90% of the class. Controversy surrounds who the sister groups of Hydroidolina are, but research has shown that three orders remain consistent as direct relatives: Siphonophorae, Anthoathecata, and Leptothecata.

<span class="mw-page-title-main">Leptothecata</span> Order of cnidarians with hydrothecae

Leptothecata, or thecate hydroids, are an order of hydrozoans in the phylum Cnidaria. Their closest living relatives are the athecate hydroids, which are similar enough to have always been considered closely related, and the very apomorphic Siphonophorae, which were placed outside the "Hydroida". Given that there are no firm rules for synonymy for high-ranked taxa, alternative names like Leptomedusa, Thecaphora or Thecata, with or without the ending emended to "-ae", are also often used for Leptothecata.

<i>Porpita porpita</i> Species of hydrozoan

Porpita porpita, or the blue button, is a marine organism consisting of a colony of hydroids found in the warmer, tropical and sub-tropical waters of the Pacific, Atlantic, and Indian oceans, as well as the Mediterranean Sea and eastern Arabian Sea. It was first identified by Carl Linnaeus in 1758, under the basionym Medusa porpita. In addition, it is one of the two genera under the suborder Chondrophora, which is a group of cnidarians that also includes Velella. The chondrophores are similar to the better-known siphonophores, which includes the Portuguese man o' war, or Physalia physalis. Although it is superficially similar to a jellyfish, each apparent individual is actually a colony of hydrozoan polyps. The taxonomic class, Hydrozoa, falls under the phylum Cnidaria, which includes anemones, corals, and jellyfish, which explains their similar appearances.

<i>Millepora platyphylla</i> Species of hydrozoan

Millepora platyphylla is a species of fire coral, a type of hydrocoral, in the family Milleporidae. It is also known by the common names blade fire coral and plate fire coral. It forms a calcium carbonate skeleton and has toxic, defensive polyps that sting. It obtains nutrients by consuming plankton and via symbiosis with photosynthetic algae. The species is found from the Red Sea and East Africa to northern Australia and French Polynesia. It plays an important role in reef-building in the Indo-Pacific region. Depending on its environment, it can have a variety of different forms and structures.

<i>Turritopsis nutricula</i> Species of hydrozoan

Turritopsis nutricula is a small hydrozoan that once reaching adulthood, can transfer its cells back to childhood. This adaptive trait likely evolved in order to extend the life of the individual. Several different species of the genus Turritopsis were formerly classified as T. nutricula, including the "immortal jellyfish" which is now classified as T. dohrnii.

Maeotias is a genus of hydrozoans in the family Olindiidae. It is a monotypic genus with only a single species, Maeotias marginata, commonly known as the Black Sea jellyfish or brackish water hydromedusa and often referred to as Maeotias inexpectata in the literature. It was first described from the Don and Kuban estuaries of the Sea of Azov, and also occurs in the Black Sea, all of which are areas of low salinity. It has been recorded in several other estuarine locations around the world and is regarded as an invasive species.

In biology, Gonozooids are any of the reproductive individuals of Tunicates, Bryozoan, or Hydrozoan colonies that produce gametes. Gonozooids may play a role in labour division or in alternation of generations. A gonozooid typically has hardly any other function than reproduction, amounting to little more than a motile gonad.

<i>Clytia hemisphaerica</i> Species of hydrozoan

Clytia hemisphaerica is a small hydrozoan-group cnidarian, about 1 cm in diameter, that is found in the Mediterranean Sea and the North-East Atlantic Ocean. Clytia has the free-swimming jellyfish form typical of the Hydrozoa, as well as vegetatively propagating polyps.

<i>Clava multicornis</i> Genus of hydrozoans

Clava is a monotypic genus of hydrozoans in the family Hydractiniidae. It contains only one accepted species, Clava multicornis. Other names synonymous with Clava multicornis include Clava cornea, Clava diffusa, Clava leptostyla, Clava nodosa, Clava parasitica, Clava squamata, Coryne squamata, Hydra multicornis, and Hydra squamata. The larvae form of the species has a well developed nervous system compared to its small size. The adult form is also advanced due to its ability to stay dormant during unfavorable periods.

Eoporpita is a disc or ellipse-shaped Ediacaran fossil with unsure taxonomy/classification. It is known from its type species, Eoporpitamedusa, the only species within the genus Eoporpita.

<span class="mw-page-title-main">Rosalindidae</span>

Rosalindidae is a family of cnidarians belonging to the order Anthoathecata.

Halisiphonia is a genus of deep water hydrozoans belonging to the family Hebellidae. There is little known about individual species. This lack of information has resulted from the difficulty of studying members of this genus due to the great depths at which they are located.

<i>Zanclea</i>

Zanclea is a genus of hydrozoans belonging to the family Zancleidae.

Tima nigroannulata, commonly known as the elegant jellyfish, is a recently discovered colonial hydrozoa found on the Pacific coast of Japan.

References

  1. 1 2 "Zancleidae". www.gbif.org. Retrieved 13 June 2021.
  2. 1 2 Montano, Simone; Arrigoni, Roberto; Pica, Daniela; Maggioni, Davide; Puce, Stefania (2014-08-27). "New insights into the symbiosis betweenZanclea(Cnidaria, Hydrozoa) and scleractinians". Zoologica Scripta. 44 (1): 92–105. doi:10.1111/zsc.12081. ISSN   0300-3256.
  3. 1 2 3 4 5 6 7 8 9 Maggioni, Davide; Arrigoni, Roberto; Galli, Paolo; Berumen, Michael L.; Seveso, Davide; Montano, Simone (2018-08-20). "Polyphyly of the genus Zanclea and family Zancleidae (Hydrozoa, Capitata) revealed by the integrative analysis of two bryozoan-associated species". Contributions to Zoology. 87 (2): 87–104. doi:10.1163/18759866-08702003. hdl: 10754/665270 . ISSN   1383-4517.
  4. 1 2 3 4 5 6 7 8 9 10 Altuna, Álvaro (2016-02-10). "The life cycle of symbiotic Zanclea sessilis (Hydrozoa: Zancleidae) colonies with polymorphic hydranths from the Bay of Biscay". Marine Biodiversity. 46 (4): 901–910. doi:10.1007/s12526-016-0456-7. ISSN   1867-1616.
  5. 1 2 3 Boero, F.; Hewitt, C. L. (1992-09-01). "A hydrozoan, Zanclella bryozoophila n.gen., n.sp. (Zancleidae), symbiotic with a bryozoan, with a discussion of the Zancleoidea". Canadian Journal of Zoology. 70 (9): 1645–1651. doi:10.1139/z92-229. ISSN   0008-4301.
  6. 1 2 Maggioni D, Schiavo A, Ostrovsky A, Seveso D, Galli P, Arrigoni R, Berumen M, Benzoni F, Montano S (2020). Cryptic species and host specificity in the bryozoan-associated hydrozoan Zanclea divergens (Hydrozoa, Zancleidae). Academic Press. OCLC   1308935703.
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