Phoronis australis

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Phoronis australis
Phoronis australis.jpg
Specimen at
Osaka Museum of Natural History
Scientific classification
Kingdom: Animalia
Phylum: Phoronida
Family: Phoronidae
Genus: Phoronis
Species:P. australis
Binomial name
Phoronis australis
Haswell, 1883 [1]
Synonyms [1]
  • Phoronis bhadurii Ganguly & Majumbar, 1967
  • Phoronis buskii McIntosh, 1888

Phoronis australis is a species of marine horseshoe worm in the phylum Phoronida. It is found in shallow warm-temperate and tropical waters in the eastern Atlantic Ocean and the Indo-Pacific region and was first detected in the Mediterranean Sea in the late twentieth century. These worms live in association with tube-dwelling anemones, particularly those in the genus Cerianthus .

In biology, a species ( ) is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. While these definitions may seem adequate, when looked at more closely they represent problematic species concepts. For example, the boundaries between closely related species become unclear with hybridisation, in a species complex of hundreds of similar microspecies, and in a ring species. Also, among organisms that reproduce only asexually, the concept of a reproductive species breaks down, and each clone is potentially a microspecies.

In biology, a phylum is a level of classification or taxonomic rank below kingdom and above class. Traditionally, in botany the term division has been used instead of phylum, although the International Code of Nomenclature for algae, fungi, and plants accepts the terms as equivalent. Depending on definitions, the animal kingdom Animalia or Metazoa contains approximately 35 phyla, the plant kingdom Plantae contains about 14, and the fungus kingdom Fungi contains about 8 phyla. Current research in phylogenetics is uncovering the relationships between phyla, which are contained in larger clades, like Ecdysozoa and Embryophyta.

Phoronid phylum of marine animals, horseshoe worms

Phoronids are a small phylum of marine animals that filter-feed with a lophophore, and build upright tubes of chitin to support and protect their soft bodies. They live in most of the oceans and seas including the Arctic Ocean but excluding the Antarctic Ocean, and between the intertidal zone and about 400 meters down. Most adult phoronids are 2 cm long and about 1.5 mm wide, although the largest are 50 cm long.

Contents

Description

Phoronis australis grows to a length of about 200 mm (8 in) when extended, with a diameter of about 2 to 5 mm (0.1 to 0.2 in). The lophophore takes the form of a double spiral and there are up to one thousand tentacles on either side. The colour is variable and may be pink, dark red or black. [2]

Lophophore

The lophophore is a characteristic feeding organ possessed by four major groups of animals: the Brachiopoda, Bryozoa, Hyolitha, and Phoronida, which collectively constitute the protostome group Lophophorata. All lophophores are found in aquatic organisms.

Tentacle varied organ found in many animals and used for palpation and manipulation

In zoology, a tentacle is a flexible, mobile, elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work mainly like muscular hydrostats. Most forms of tentacles are used for grasping and feeding. Many are sensory organs, variously receptive to touch, vision, or to the smell or taste of particular foods or threats. Examples of such tentacles are the "eye stalks" of various kinds of snails. Some kinds of tentacles have both sensory and manipulatory functions.

Distribution and habitat

Phoronis australis is native to the Indo-Pacific region and the southeastern Atlantic Ocean. Since the 1990s it has appeared in the Mediterranean Sea, presumably arriving via the Strait of Gibraltar as early records were from Spain. In the Mediterranean, it is normally associated with the tube-dwelling anemone Cerianthus membranaceus , with typically, about eight individual horseshoe worms being present on the tube of each host. [3] However, it has also been recorded as living independently in muddy coarse sand in the Mediterranean, the tube being attached to the seagrass Posidonia oceanica . [3]

Strait of Gibraltar strait that connects the Atlantic Ocean to the Mediterranean Sea

The Strait of Gibraltar is a narrow strait that connects the Atlantic Ocean to the Mediterranean Sea and separates Gibraltar and Peninsular Spain in Europe from Morocco and Ceuta (Spain) in Africa. The name comes from the Rock of Gibraltar, which in turn originates from the Arabic Jebel Tariq named after Tariq ibn Ziyad. It is also known as the Straits of Gibraltar, the Gut of Gibraltar, the STROG in naval use, and Bab Al Maghrib, "Gate of the West". In the Middle Ages, Muslims called it Al-Zuqaq, "The Passage", the Romans called it Fretum Gatitanum, and in the ancient world it was known as the "Pillars of Hercules".

<i>Cerianthus membranaceus</i> species of cnidarian

Cerianthus membranaceus, the cylinder anemone or coloured tube anemone, is a species of large, tube-dwelling anemone in the family Cerianthidae. It is native to the Mediterranean Sea and adjoining parts of the northeastern Atlantic Ocean.

Host (biology) Organism that harbours another organism

In biology and medicine, a host is an organism that harbours a parasitic, a mutualistic, or a commensalist guest (symbiont), the guest typically being provided with nourishment and shelter. Examples include animals playing host to parasitic worms, cells harbouring pathogenic (disease-causing) viruses, a bean plant hosting mutualistic (helpful) nitrogen-fixing bacteria. More specifically in botany, a host plant supplies food resources to micropredators, which have an evolutionarily stable relationship with their hosts similar to ectoparasitism. The host range is the collection of hosts that an organism can use as a partner.

Ecology

Phoronis australis secretes a chitinous tube into which it can retreat when disturbed. The tube is attached to the much larger tube of a tube-dwelling anemone which lives in shallow sheltered water immersed in soft sediment. Many horseshoe worms may be associated with a single ceriantharian anemone. [4] The lophophore of the horseshoe worm is extended to catch the planktonic particles on which it feeds. It benefits from the protection provided by the canopy of anemone tentacles and is alerted to danger by the reactions of the anemone in withdrawing into its tube when disturbed. The anemone probably derives no benefit from the inquiline association. [5]

Tube-dwelling anemone order of cnidarians

Tube-dwelling anemones or ceriantharians look very similar to sea anemones but belong to an entirely different subclass of anthozoans. They are solitary, living buried in soft sediments. Tube anemones live inside and can withdraw into tubes, which are composed of a fibrous material made from secreted mucus and threads of nematocyst-like organelles known as ptychocysts. Ceriantharians were formerly classified in the taxon Ceriantipatharia along with the black corals but have since been moved to their own subclass, Ceriantharia.

Inquiline

In zoology, an inquiline is an animal that lives commensally in the nest, burrow, or dwelling place of an animal of another species. For example, some organisms such as insects may live in the homes of gophers and feed on debris, fungi, roots, etc. The most widely distributed types of inquiline are those found in association with the nests of social insects, especially ants and termites – a single colony may support dozens of different inquiline species. The distinctions between parasites, social parasites, and inquilines are subtle, and many species may fulfill the criteria for more than one of these, as inquilines do exhibit many of the same characteristics as parasites. However, parasites are specifically not inquilines, because by definition they have a deleterious effect on the host species, while inquilines do not.

P. australis is a hermaphrodite. The embryos are at first brooded in two clumps on mucus threads secreted by nidamental glands. [2] The actinotroch larvae are planktonic and eventually settle and undergo metamorphosis. [4] The horseshoe worm can also reproduce asexually by transverse fission. [2]

Hermaphrodite organism with both male and female reproductive organs

In biology, a hermaphrodite is an organism that has complete or partial reproductive organs and produces gametes normally associated with both male and female sexes. Many taxonomic groups of animals do not have separate sexes. In these groups, hermaphroditism is a normal condition, enabling a form of sexual reproduction in which either partner can act as the "female" or "male." For example, the great majority of tunicates, pulmonate snails, opisthobranch snails, earthworms and slugs are hermaphrodites. Hermaphroditism is also found in some fish species and to a lesser degree in other vertebrates. Most plants are also hermaphrodites.

Plankton Organisms that live in the water column and are incapable of swimming against a current

Plankton are the diverse collection of organisms that live in large bodies of water and are unable to swim against a current. The individual organisms constituting plankton are called plankters. They provide a crucial source of food to many large aquatic organisms, such as fish and whales.

Metamorphosis profound change in body structure during the postembryonic development of an organism

Metamorphosis is a biological process by which an animal physically develops after birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Metamorphosis is iodothyronine-induced and an ancestral feature of all chordates. Some insects, fishes, amphibians, mollusks, crustaceans, cnidarians, echinoderms, and tunicates undergo metamorphosis, which is often accompanied by a change of nutrition source or behavior. Animals that go through metamorphosis are called metamorphoses. Animals can be divided into species that undergo complete metamorphosis ("holometaboly"), incomplete metamorphosis ("hemimetaboly"), or no metamorphosis ("ametaboly").

Related Research Articles

Marine worm

Any worm that lives in a marine environment is considered a marine worm. Marine worms are found in several different phyla, including the Platyhelminthes, Nematoda, Annelida, Chaetognatha, Hemichordata, and Phoronida. For a list of marine animals that have been called "sea worms", see sea worm.

Anthozoa class of cnidarians

Anthozoa is a class of marine invertebrates which includes the sea anemones, stony corals, soft corals and gorgonians. Adult anthozoans are almost all attached to the seabed, while their larvae can disperse as part of the plankton. The basic unit of the adult is the polyp; this consists of a cylindrical column topped by a disc with a central mouth surrounded by tentacles. Sea anemones are mostly solitary, but the majority of corals are colonial, being formed by the budding of new polyps from an original, founding individual. Colonies are strengthened by calcium carbonate and other materials and take various massive, plate-like, bushy or leafy forms.

<i>Phoronis</i> genus of horseshoe worms

Phoronis is one of the two genera of the horseshoe worm family (Phoronidae), in the phylum Phoronida. The body has two sections, each with its own coelom. There is a specialist feeding structure, the lophophore, which is an extension of the wall of the coelom and is surrounded by tentacles. The gut is U-shaped. The diagnostic feature that distinguishes this genus is the lack of epidermal invagination at the base of the lophophore. These worms are filter feeders.

<i>Sabella pavonina</i> Species of annelid

Sabella pavonina, commonly known as the peacock worm, is a marine polychaete worm belonging to the family Sabellidae. It occurs along the coasts of Western Europe and the Mediterranean. It is found in shallow, tidal waters with a bed of mud, sand or gravel. It is sometimes found on rocks or shipwrecks.

<i>Nembrotha lineolata</i> species of mollusc

Nembrotha lineolata is a species of nudibranch, a sea slug, a marine gastropod mollusk in the family Polyceridae. It is found in shallow water in the Indo-Pacific. It was first described in 1905 by the Danish malacologist Rudolph Bergh. The type locality is Selayar Island, Indonesia.

Phoronopsis is a genus of horseshoe worm in the family Phoronidae, in the phylum Phoronida. The members of the genus live in tubes at the bottom of the sea.

Phoronis psammophila is a species of marine horseshoe worm in the phylum Phoronida. It lives in a tube projecting from the sea floor in shallow seas around the world.

Phoronopsis californica is a species of marine horseshoe worm in the phylum Phoronida. It was first described as a new species by William Hilton in 1930 when he found it at Balboa Bay, California.

<i>Pagurus prideaux</i> species of crustacean

Pagurus prideaux is a species of hermit crab in the family Paguridae. It is found in shallow waters off the northwest coast of Europe and usually lives symbiotically with the sea anemone Adamsia palliata.

<i>Triactis</i> species of cnidarian

Triactis is a genus of sea anemone in the family Aliciidae. It is monotypic, having only one species – Triactis producta. This is found in shallow waters in the Indo-Pacific where it lives on the seabed, rocks and corals. It derives much of its energy needs from the symbiotic algae it contains. It also forms a mutualistic relationship with small Lybia crabs.

Cerianthus lloydii is a species of tube-dwelling sea anemone in the family Cerianthidae. It is sometimes called the lesser cylinder anemone and is found in shallow seas around the coasts of north west Europe.

Amathia vidovici is a species of colonial bryozoans with a tree-like structure. It is found in shallow waters over a wide geographical range, being found in both the Atlantic and Pacific Oceans and adjoining seas.

<i>Cerianthus filiformis</i> species of cnidarian

Cerianthus filiformis is a species of tube-dwelling sea anemone in the family Cerianthidae.

<i>Sabella spallanzanii</i> species of annelid

Sabella spallanzanii is a species of marine polychaete worms in the family Sabellidae. Common names include the Mediterranean fanworm, the feather duster worm, the European fan worm and the pencil worm. It is native to shallow waters in the northeastern Atlantic Ocean and the Mediterranean Sea. It has spread to various other parts of the world and is included on the Global Invasive Species Database.

Phoronis ovalis is a species of marine horseshoe worm in the phylum Phoronida. It is found in shallow waters in the northeastern Atlantic Ocean, the southeastern Atlantic Ocean, Argentina, and other scattered locations worldwide. These worms secrete a tube into which they can retreat, and burrow into the shells of molluscs.

Ceriantheomorphe brasiliensis is a species of tube-dwelling anemones in the family Cerianthidae. It is found in the tropical western Atlantic Ocean, the Caribbean Sea and the Gulf of Mexico. It is currently listed as endangered based on a lack of evidence.

Serpula columbiana, variously called the calcareous tubeworm, the plume worm, the fan worm, the limy tube worm and the red tube worm, is a species of segmented marine polychaete worm in the family Serpulidae. It is a cosmopolitan species that is found in most seas in the Northern Hemisphere including the Atlantic Ocean, the Pacific Ocean and the Indian Ocean.

References

  1. 1 2 Emig, Christian (2015). "Phoronis australis Haswell, 1883". World Register of Marine Species . Retrieved 2015-05-19.
  2. 1 2 3 "Phoronis australis Haswell, 1883". Phoronida World Database. 2009-02-24. Retrieved 2015-05-19.
  3. 1 2 Consentinio, Andrea; Giacobbe, Salvatore; Potoschi, Andrea (2011). "The presence of Phoronis australis (Phoronida) in southern Italian waters" (PDF). Biogeographia. XXX.
  4. 1 2 Anderson, Donald Thomas (1996). Atlas of Invertebrate Anatomy. UNSW Press. pp. 32–. ISBN   978-0-86840-207-9.
  5. ↑ Morton, Brian (1989). Partnerships in the Sea: Hong Kong's Marine Symbioses. Kent State University Press. pp. 38–. ISBN   978-962-209-211-2.
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