Body structure consists of a thin, cylindrical, translucent umbrella that ranges from colorless to subtle shades of pink, orange, or red. The top of the umbrella forms a conical apical projection. The umbrella can grow 10 to 22 mm in height and 5 to 11 mm in width, forming its helmet-like shape. The average bell height of adults is 12 mm, but may reach up to 22 mm. Eight brightly-colored tubular gonads are suspended from underneath the top of the umbrella. The gastric peduncle is located in the central cavity and is nearly the same height as the umbrella. Attached to the gastric peduncle are eight radial canals along with the gastrovascular cavity. Usually, (Colin, et al., 2003; Meech, 2004; Pertsova, et al., 2006)has up to 80 wispy tentacles that extend from the base of the umbrella, but some are found with fewer due to encounters with prey and predators.
The eggs of (von Dassow, 1998)are unusual compared to other hydrozoans. The egg contains large and irregular sized yolk globules that give it a crater-like surface. The egg then becomes a planula that remains afloat. The planula then develops into a larva called an actinula, which bears nematocysts. The actinula later develops into a medusa; there is no polyp stage in this species.
There is no specific information on how (Hammond, 2009)spawns, but hydrozoans in general are broadcast spawners.
Because most hydrozoans are broadcast spawners, there is no parental investment in the young. Larvae are planktonic, and develop independently. (Hammond, 2009)
The lifespan of this species varies among geographic populations. Individuals found in the subarctic Pacific, the North Sea, and the Northeast Atlantic have an annual life cycle. However, populations of A. digitale in Toyama Bay, Ogac Lake in Baffin Island, and the Strait of Georgia, have biennial life cycles, while up to four generations have been observed co-occurring in Norwegian fjords. (Takahashi and Ikeda, 2006)
This planktonic species has neither home range nor territory.
The inside of its bell is lined with giant ring axons and circumferentially lined with myoepithelial cells. Near the apex, there are eight giant motor axons. This primitive nervous system acts to detect any disturbance within the water or upon the animal and allows sends electrical impulses to the bell muscle fibers so that the animal can respond quickly. (Roberts and Mackie, 1980)
Diet consists of zooplankton, such as small shrimps and other planktonic organisms including microalgae, copepods, and tintinnids.
Some of the known predators of leatherback turtle, larger medusa jellyfish, and the bearded goby. Another predator of is Flabellina goddardi, a sea slug able to consume this type of prey because the slug is unaffected by the hydroid's defensive nematocysts.are the
This species has no current commercial value.
There are no known adverse effects ofon humans.
This species is not threatened, nor is it currently managed.
Angelabelle Abarientos (author), San Diego Mesa College, Adolfo Nunez (author), San Diego Mesa College, Paul Detwiler (editor), San Diego Mesa College, Renee Mulcrone (editor), Special Projects.
the body of water between Europe, Asia, and North America which occurs mostly north of the Arctic circle.
the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.
body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.
an animal that mainly eats meat
the nearshore aquatic habitats near a coast, or shoreline.
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
uses electric signals to communicate
fertilization takes place outside the female's body
union of egg and spermatozoan
having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.
Animals with indeterminate growth continue to grow throughout their lives.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
specialized for swimming
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
An aquatic biome consisting of the open ocean, far from land, does not include sea bottom (benthic zone).
generates and uses light to communicate
photosynthetic or plant constituent of plankton; mainly unicellular algae. (Compare to zooplankton.)
an animal that mainly eats plankton
the regions of the earth that surround the north and south poles, from the north pole to 60 degrees north and from the south pole to 60 degrees south.
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
a form of body symmetry in which the parts of an animal are arranged concentrically around a central oral/aboral axis and more than one imaginary plane through this axis results in halves that are mirror-images of each other. Examples are cnidarians (Phylum Cnidaria, jellyfish, anemones, and corals).
mainly lives in oceans, seas, or other bodies of salt water.
breeding is confined to a particular season
reproduction that includes combining the genetic contribution of two individuals, a male and a female
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
an animal which has an organ capable of injecting a poisonous substance into a wound (for example, scorpions, jellyfish, and rattlesnakes).
movements of a hard surface that are produced by animals as signals to others
breeding takes place throughout the year
animal constituent of plankton; mainly small crustaceans and fish larvae. (Compare to phytoplankton.)
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