''Botrylloides leachii'' is a

colonial Colonial or The Colonial may refer to: * Colonial, of, relating to, or characteristic of a colony or colony (biology) Architecture * American colonial architecture * French Colonial * Spanish Colonial architecture Automobiles * Colonial (1920 a ...

tunicate A tunicate is a marine invertebrate animal, a member of the subphylum Tunicata (). It is part of the Chordata, a phylum which includes all animals with dorsal nerve cords and notochords (including vertebrates). The subphylum was at one time ...

of the family

Styelidae Styelidae is a family of ascidian tunicates.Lambert, G.; Gittenberger, A.; Sanamyan, K. (2015)Styelidae Sluiter, 1895.In: Shenkar, N.; Gittenberger, A.; Lambert, G.; Rius, M.; Moreira Da Rocha, R.; Swalla, B.J.; Turon, X. (2015) Ascidiacea World ...

. Its unique methods of propagation and regeneration make it an ideal model organism for use in biological study of development, immunology, stem cells, and regeneration.

Description

''Botrylloides leachii'' is a

tunicate and can form a flat gelatinous encrusting sheet or a more massive structure. The individual

zooid A zooid or zoöid is a single animal that is part of a colonial animal. This lifestyle has been adopted by animals from separate unrelated taxa. Zooids are multicellular; their structure is similar to that of other solitary animals. The zooid ...

s are about in diameter while the whole colony may reach or more across. Groups of zooids tend to form pairs of parallel chains; each zooid has its own inhalant siphon but the groups share an exhalant siphon. The tunic is some shade of grey, pink, orange, yellow or white; the siphons have white rims, and the exhalant siphons have white radial streaks.

Distribution and habitat

''Botrylloides leachii'' has a wide distribution, with a number of species previously thought to be separate having been shown to be identical and

synonym A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are al ...

ised with it. Its range includes the Indo-Pacific region, the Caribbean Sea and the Eastern Atlantic Ocean including the

North Sea The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian S ...

and the

Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...

. It grows on rock, various hard substrates and large seaweeds, as well as loose on sand and

detritus In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commu ...

, at depths down to about .

Biology

Like all tunicates, ''Botrylloides leachii'' is a filter feeder that feeds by drawing water into its interior through the inhalant siphon, filtering out the edible particles with a mucus net, and expelling the water and waste products through the exhalant siphon. The sexes are separate in this species, and the

gamete A gamete (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. In species that produce ...

s are liberated into the

water column A water column is a conceptual column of water from the surface of a sea, river or lake to the bottom sediment.Munson, B.H., Axler, R., Hagley C., Host G., Merrick G., Richards C. (2004).Glossary. ''Water on the Web''. University of Minnesota-D ...

. The larvae are planktonic at first but soon settle on the seabed where they undergo metamorphosis into zooids with adult organs. A founding zooid begins to form buds which grow into new zooids, which in turn bud again, and the colony expands. The zooids are connected by a network of blood vessels with minute finger-like processes called "ampullae". In time, the older zooids begin to degrade and become reabsorbed while the colony lives on. Whole-body regeneration is extremely unusual among

chordate A chordate () is an animal of the phylum Chordata (). All chordates possess, at some point during their larval or adult stages, five synapomorphies, or primary physical characteristics, that distinguish them from all the other taxa. These five ...

s, but a colony of ''Botrylloides leachii'' can regenerate itself from a small piece of tissue. In a colony where all the zooids have been removed and the only structure that remains is the linking vascular tissue,

blood cell A blood cell, also called a hematopoietic cell, hemocyte, or hematocyte, is a cell produced through hematopoiesis and found mainly in the blood. Major types of blood cells include red blood cells (erythrocytes), white blood cells (leukocytes), ...

s aggregate to initiate repairs,

white blood cell White blood cells, also called leukocytes or leucocytes, are the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders. All white blood cells are produced and derived from mult ...

s infiltrate the wounds and macrophage-like cells ingest the debris. Within ten days, the macrophages have disappeared from the circulation and the zooids have regenerated. The ampullae are the seat of the regeneration process; researchers successfully grew 80 out of 95 sections of blood vessel with ampullae attached into new zooids, with a sexually mature zooid developing in about two weeks.

References

External links

* {{Taxonbar, from=Q13442912 Stolidobranchia Fauna of the Atlantic Ocean Fauna of the Indian Ocean Fauna of the Mediterranean Sea Fauna of the Pacific Ocean Animals described in 1816 Taxa named by Marie Jules César Savigny