The starburst anemone or sunburst anemone (''Anthopleura sola'') is a
species
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. It is the basic unit of Taxonomy (biology), ...
of
sea anemone
Sea anemones ( ) are a group of predation, predatory marine invertebrates constituting the order (biology), order Actiniaria. Because of their colourful appearance, they are named after the ''Anemone'', a terrestrial flowering plant. Sea anemone ...
in the
family
Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...
Actiniidae
Actiniidae is the largest family (biology), family of sea anemones, to which most common, temperate, shore species belong. Most members of this family do not participate in symbiosis, symbioses with fishes. Three exceptions are the bubble-tip an ...
. The sunburst anemone was formerly considered the solitary form of the common
aggregating anemone, but was identified as a separate species in 2000.
Description
The sunburst anemone is a solitary anemone that averages but can grow up to wide, much larger than the aggregating anemone.
The column is pale green to white in color and is twice as long as its width when extended. The column has numerous sticky protuberances (called verrucae) arranged in vertical rows to which gravel and shell fragments adhere. The oral disc is radially striped and has five rings of thick, pointed feeding tentacles. Tentacles are pale with the tips colored in pink, blue or lavender.
The sunburst anemone can be differentiated from the aggregating anemone by its larger size and usual solitary form. It is differentiated from ''
Anthopleura xanthogrammica'' by the coloration of the tentacle tips, striped oral disk, and vertical rows of verrucae.
The color of the anemone is partly caused by
symbiotic
Symbiosis (Ancient Greek : living with, companionship < : together; and ''bíōsis'': living) is any type of a close and long-term biolo ...
''
Zooxanthella
Zooxanthellae (; zooxanthella) is a colloquial term for single-celled photosynthetic organisms that are able to live in symbiosis with diverse marine invertebrates including corals, jellyfish, demosponges, and nudibranchs. Most known zooxanthell ...
e'' in the gastrodermal layer. This species of anemone reproduces sexually.
Distribution and habitat
The sunburst anemone is found in the north west Pacific Ocean. In the United States it occurs between central
California
California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
and
Baja California
Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...
. It lives in the lower intertidal zone in rocky habitats, often in the shelter of cracks and crevices. It also occurs in the subtidal, often in kelp forests, to depths of at least .
When the tide is out it is often concealed by shell fragments and other particles that adhere to the column, which folds into an encrusted ball.
[ The encrusted column may serve as camouflage from predators as well as protection from solar radiation and desiccation.]
Territorial defense
The sunburst anemone aggressively defends its territory from other anemones which are genetically dissimilar. When it encounters a different genetic colony, the anemones extend specialized tentacles (called acrorhagi). The white tips of acrorhagi have a concentration of stinging cells ( nematocytes) and are used solely to deter other colonies from encroaching on their space. The nematocysts sting the ectoderm
The ectoderm is one of the three primary germ layers formed in early embryonic development. It is the outermost layer, and is superficial to the mesoderm (the middle layer) and endoderm (the innermost layer). It emerges and originates from the o ...
of the invader, causing tissue necrosis
Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. The term "necrosis" came about in the mid-19th century and is commonly attributed to German pathologist Rudolf Virchow, who i ...
and forcing the competitor to move away. The similar aggregating anemone also possesses acrorhagi.
References
Actiniidae
Animals described in 2000
External links
* {{YouTube, 1v2DYzcv46I, Encrusted and contracting upon touch