Siphonophorae or
Siphonophora, the
siphonophores, are an
orderIn scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
of the
HydrozoaHydrozoa are a taxonomic class of very small, predatory animals which can be solitary or colonial and which mostly live in saltwater. A few genera within this class live in freshwater...
, a class of marine
invertebrateAn invertebrate is an animal without a vertebral column. The group includes 95% of all animal species — all animals except those in the Chordate subphylum Vertebrata ....
s belonging to the phylum
CnidariaCnidaria is a phylum containing over 10,000 species of animals found exclusively in aquatic, mostly marine, environments. Their distinguishing feature is cnidocytes, specialized cells that they use mainly for capturing prey...
. They are
colonialIn biology, a colony refers to several individual organisms of the same species living closely together, usually for mutual benefit, such as stronger defences or the ability to attack bigger prey. Some insects live only in colonies...
, but the colonies can superficially resemble
jellyfishJellyfish are free-swimming members of the phylum Cnidaria. Jellyfish have several different morphologies that represent several different cnidarian classes including the Scyphozoa , Staurozoa , Cubozoa , and Hydrozoa Jellyfish (also known as jellies or sea jellies) are free-swimming members of...
; although they appear to be a single
organismIn biology, an organism is any living system . In at least some form, all organisms are capable of response to stimuli, reproduction, growth and development, and maintenance of homeostasis as a stable whole...
, each specimen is actually a colony of Siphonophora. The best known species is the dangerous
Portuguese Man o' WarThe Portuguese Man o' War , also known as the blue bubble, blue bottle, man-of-war, or the Portuguese man of war, is a jelly-like, marine invertebrate of the family Physaliidae....
(
Physalia physalis).
Siphonophores are especially scientifically interesting because they are composed of
medusoidIn biology, a medusa is a form of cnidarian in which the body is shortened on its principal axis and broadened, sometimes greatly, in contrast with polyps. Medusae vary from bell-shaped to the shape of a thin disk, scarcely convex above and only slightly concave below...
and
polypoidA polyp in zoology is one of two forms found in the phylum Cnidaria, the other being the medusa. Polyps are approximately cylindrical in shape and elongated at the axis of the body...
zooids that are
morphologicallyIn biology morphology is the form, structure and configuration of an organism.This includes aspects of the outward appearance as well as the form and structure of the internal parts like bones and organs...
and functionally specialized.
Siphonophorae or
Siphonophora, the
siphonophores, are an
orderIn scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
of the
HydrozoaHydrozoa are a taxonomic class of very small, predatory animals which can be solitary or colonial and which mostly live in saltwater. A few genera within this class live in freshwater...
, a class of marine
invertebrateAn invertebrate is an animal without a vertebral column. The group includes 95% of all animal species — all animals except those in the Chordate subphylum Vertebrata ....
s belonging to the phylum
CnidariaCnidaria is a phylum containing over 10,000 species of animals found exclusively in aquatic, mostly marine, environments. Their distinguishing feature is cnidocytes, specialized cells that they use mainly for capturing prey...
. They are
colonialIn biology, a colony refers to several individual organisms of the same species living closely together, usually for mutual benefit, such as stronger defences or the ability to attack bigger prey. Some insects live only in colonies...
, but the colonies can superficially resemble
jellyfishJellyfish are free-swimming members of the phylum Cnidaria. Jellyfish have several different morphologies that represent several different cnidarian classes including the Scyphozoa , Staurozoa , Cubozoa , and Hydrozoa Jellyfish (also known as jellies or sea jellies) are free-swimming members of...
; although they appear to be a single
organismIn biology, an organism is any living system . In at least some form, all organisms are capable of response to stimuli, reproduction, growth and development, and maintenance of homeostasis as a stable whole...
, each specimen is actually a colony of Siphonophora. The best known species is the dangerous
Portuguese Man o' WarThe Portuguese Man o' War , also known as the blue bubble, blue bottle, man-of-war, or the Portuguese man of war, is a jelly-like, marine invertebrate of the family Physaliidae....
(
Physalia physalis).
Description
Siphonophores are especially scientifically interesting because they are composed of
medusoidIn biology, a medusa is a form of cnidarian in which the body is shortened on its principal axis and broadened, sometimes greatly, in contrast with polyps. Medusae vary from bell-shaped to the shape of a thin disk, scarcely convex above and only slightly concave below...
and
polypoidA polyp in zoology is one of two forms found in the phylum Cnidaria, the other being the medusa. Polyps are approximately cylindrical in shape and elongated at the axis of the body...
zooids that are
morphologicallyIn biology morphology is the form, structure and configuration of an organism.This includes aspects of the outward appearance as well as the form and structure of the internal parts like bones and organs...
and functionally specialized. Siphonophores have been known to grow up to 130 feet in length. Each zooid is an individual, but their integration with each other is so strong that the colony attains the character of one large organism. Indeed, most of the zooids are so specialized that they lack the ability to survive on their own. Siphonophorae thus exist at the boundary between colonial and complex multicellular organisms. Also, because multicellular organisms have cells which, like zooids, are specialized and interdependent, siphonophores may provide clues regarding their
evolutionIn biology, evolution is change in the genetic material of a population of organisms from one generation to the next. Though changes produced in any one generation are normally small, differences accumulate with each generation and can, over time, cause substantial changes in the population, a...
.
Like other
hydrozoaHydrozoa are a taxonomic class of very small, predatory animals which can be solitary or colonial and which mostly live in saltwater. A few genera within this class live in freshwater...
ns, certain siphonophores can emit light. A siphonophore of the
genusIn biology, a genus is a taxonomic unit used in the classification of living and fossil organisms. The term comes from Latin genus "descent, family, type, gender" , cognate with – genos, "race, stock, kin" ..In addition, genus is a taxonomic rank in the hierarchy In biology, a genus (plural:...
Erenna has been discovered at a depth of around 1,600 meters off the coast of
Monterey, CaliforniaThe City of Monterey in Monterey County is located on Monterey Bay along the Pacific coast in Central California. Variants of the city's name are recorded as Monte Rey and Montery. Monterey lies at an elevation of 26 feet above sea level. As of 2005, the city population was 30,641...
. The individuals from these colonies are strung together like a
feather boaA feather boa is a fashion accessory that is usually worn wrapped around the neck like a scarf.-Construction:A boa can be made of fur, but it is usually made instead from various types of feathers. Ostrich, marabou, chandelle, and turkey are the most common feathers used, although non-feather boas...
. They prey on small animals using stinging cells. Among the stinging cells are stalks with red glowing ends. The tips twitch back and forth creating a twinkling effect. It is theorized that twinkling red light attracts small fish that have been found eaten by these siphonophores. While many sea animals produce blue and green
bioluminescenceBioluminescence is the production and emission of light by a living organism. Its name is a hybrid word, originating from the Greek bios for "living" and the Latin lumen "light". Bioluminescence is a naturally occurring form of chemiluminescence where energy is released by a chemical reaction in...
, this siphonophore was only the second lifeform found to produce a red light (the first being the Scaleless Dragonfish,
Chirostomias pliopterus).
Systematics
Due to their highly specialized colonies, siphonophores have long misled scientists. They were for a long time believed to be a highly distinct group, but now are known to have evolved from simpler colonial hydrozoans similar to
AnthomedusaeAnthomedusae or Anthomedusa, the athecate hydroids, are an order of the Hydrozoa, a class of marine invertebrates belonging to the phylum Cnidaria...
or
LeptomedusaeLeptomedusae or Leptomedusa, commonly called thecate hydroids, are a cnidarian order in the subclass Leptolinae. They were formerly placed at suborder rank in the paraphyletic "Hydroida"...
. Consequently, they are now united with these in a
subclassSubclass may refer to:* Class , a taxonomic rank intermediate between class and superorder* Subclass , a class that is derived from another class or classes...
LeptolinaeLeptolinae are a cnidarian subclass of the Hydrozoa. They contain the bulk of the paraphyletic "Hydroida" which were one of the main groupings of the Hydrozoa in older classifications and were placed at order rank...
.
The Siphonophorae have long fascinated scientists and layfolk alike, due to their dramatic appearance as well as the large size and dangerous sting of several
speciesIn biology, a species is:* a taxonomic rank or* a unit at that rank ....
. Compared to their relatives, their
systematicsBiological systematics is the study of the diversification of life on the planet Earth, both past and present, and the relationships among living things through time. Relationships are visualized as evolutionary trees...
are relatively straightforward:
Suborder Calycophorae
- Family Abylidae
- Family Clausophyidae
- Family Diphyidae
- Family Hippopodiidae
- Family Prayidae
- Family Sphaeronectidae
Suborder Cystonectae
- Family Physaliidae
- Family Rhizophysidae
Suborder Physonectae
- Family Agalmatidae
- Family Apolemiidae
- Family Athorybiidae
- Family Erennidae
- Family Forskaliidae
- Family Physophoridae
- Family Pyrostephidae
- Family Rhodaliidae
The genus
Stepanyantsia is of unclear affiliations; it might belong in the Agalmatidae.
Haeckel's siphonophores
Ernst HaeckelErnst Heinrich Philipp August Haeckel ,also written von Haeckel, was an eminent German biologist, naturalist, philosopher, physician, professor and artist who discovered, described and named thousands of new species, mapped a genealogical tree relating all life forms, and coined many terms in...
described a number of siphonophores, and several plates from his
Kunstformen der NaturKunstformen der Natur is a book of lithographic and autotype prints by German biologist Ernst Haeckel. Originally published in sets of ten between 1899 and 1904 and as a complete volume in 1904, it consists of 100 prints of various organisms, many of which were first described by Haeckel himself...
(1904) depict members of the
taxon|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement. Defining what belongs or does not belong to such a...
:
External links
- http://siphonophores.org
- http://www.ville-ge.ch/musinfo/mhng/hydrozoa/sipho/siphonophora.htm
- http://www.youtube.com/watch?v=KT1TSbarW1U