Siphonoglyph
Encyclopedia
The siphonoglyph is a ciliated groove at one or both ends of the mouth of sea anemone
s and some coral
s. The siphonoglyph extends into a pharynx
and is used to create currents of water into the pharynx. These water currents are important for respiration
and maintenance of internal pressure. The presence of a siphonoglyph (or 2 siphonoglyphs) in several anthozoans (including species from the orders Zoantharia
, Ceriantharia, Antipitharia, and Octocorallia) introduces an element of bilateral symmetry into the particular species' body plan (Beklemishev 1969). Some have argued that the presence of bilaterial symmetry in these anthozoans is evidence that the ancestor to bilaterians and cnidarians may have had a bilaterally symmetrical body plan (Finnerty 2003).
Sea anemone
Sea anemones are a group of water-dwelling, predatory animals of the order Actiniaria; they are named after the anemone, a terrestrial flower. Sea anemones are classified in the phylum Cnidaria, class Anthozoa, subclass Zoantharia. Anthozoa often have large polyps that allow for digestion of larger...
s and some coral
Coral
Corals are marine animals in class Anthozoa of phylum Cnidaria typically living in compact colonies of many identical individual "polyps". The group includes the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton.A coral "head" is a colony of...
s. The siphonoglyph extends into a pharynx
Pharynx
The human pharynx is the part of the throat situated immediately posterior to the mouth and nasal cavity, and anterior to the esophagus and larynx. The human pharynx is conventionally divided into three sections: the nasopharynx , the oropharynx , and the laryngopharynx...
and is used to create currents of water into the pharynx. These water currents are important for respiration
Aquatic respiration
Aquatic respiration is the process whereby an aquatic animal obtains oxygen from water.-Fish:In most fish respiration takes place through gills. Lungfish, however, possess one or two lungs...
and maintenance of internal pressure. The presence of a siphonoglyph (or 2 siphonoglyphs) in several anthozoans (including species from the orders Zoantharia
Zoantharia
Zoanthids are an order of cnidarians commonly found in coral reefs, the deep sea and many other marine environments around the world. These animals come in a variety of different colonizing formations and in numerous colors...
, Ceriantharia, Antipitharia, and Octocorallia) introduces an element of bilateral symmetry into the particular species' body plan (Beklemishev 1969). Some have argued that the presence of bilaterial symmetry in these anthozoans is evidence that the ancestor to bilaterians and cnidarians may have had a bilaterally symmetrical body plan (Finnerty 2003).