''Anthopleura ballii'', commonly known as the red speckled anemone, 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 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 ...

. It is found in shallow water in the northeastern Atlantic Ocean.

Description

''Anthopleura ballii'' has a broad base up to across and a trumpet-shaped column up to high. The surface of the column bears forty-eight longitudinal rows of small warts, each tipped with red. The oral disc is wide and there are up to 96 tapering tentacles arranged in five whorls. These are retractable to a limited extent and are flecked with white. The colouring of this species is variable, being some shade of red or yellow, with the tentacles sometimes having an iridescent green sheen. The warts are non-adhesive. This is in contrast to the closely related glaucous pimplet (''Anthopleura thallia''), which has gravel or debris adhering to the column.

Distribution and habitat

''Anthopleura ballii'' is native to northeastern Atlantic Ocean and the coasts of Western Europe. It is found on rocky coasts from the

intertidal zone The intertidal zone or foreshore is the area above water level at low tide and underwater at high tide; in other words, it is the part of the littoral zone within the tidal range. This area can include several types of habitats with various ...

down to depths of about . It usually occurs in crevices, in the holes made by piddocks as they burrow, under boulders and in other concealed locations. It is sometimes attached to pebbles and shells and may be semi-immersed in sand or mud.

Biology

''Anthopleura ballii'' contains unicellular

dinoflagellate The Dinoflagellates (), also called Dinophytes, are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered protists. Dinoflagellates are mostly marine plankton, but they are also commo ...

s living inside the tissues. These are species of ''

Symbiodinium ''Symbiodinium'' is a genus of dinoflagellates that encompasses the largest and most prevalent group of endosymbiotic dinoflagellates known and have photosymbiotic relationships with many species. These unicellular microalgae commonly reside in ...

'' and are commonly known as zooxanthellae. They are

photosynthetic Photosynthesis ( ) is a Biological system, system of biological processes by which Photoautotrophism, photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical ener ...

organisms and provide the sea anemone with nutrients and energy, the products of photosynthesis. This type of arrangement is common in corals and sea anemones in nutrient-deficient tropical seas but is rare in temperate waters, which tend to be nutrient-rich. Researchers have found that the ova become infected with

maternal A mother is the female parent of a child. A woman may be considered a mother by virtue of having given birth, by raising a child who may or may not be her biological offspring, or by supplying her ovum for fertilisation in the case of gestatio ...

zooxanthellae just before spawning takes place. The zooxanthellae are restricted to one side of the ovum and during the rearrangement of tissues that takes place during the development of the embryo into a planula larva, the zooxanthellae are confined to the

endoderm Endoderm is the innermost of the three primary germ layers in the very early embryo. The other two layers are the ectoderm (outside layer) and mesoderm (middle layer). Cells migrating inward along the archenteron form the inner layer of the gastr ...

of the larva and to the gastrodermal cells of the adult. This method of acquiring zooxanthellae is unusual. In tropical seas zooxanthellae are frequently liberated into the sea by symbiotic invertebrates and occur in the faeces of predators feeding on symbiotic cnidarians. This means that there is little need for maternal transfer of symbionts. This is not the case in temperate seas where free-living zooxanthellae are scarce. ''A. ballii'' is

gonochoric In biology, gonochorism is a sexual system where there are two sexes and each individual organism is either male or female. The term gonochorism is usually applied in animal species, the vast majority of which are gonochoric. Gonochorism contrast ...

, with individuals being either male or female. It is a broadcast spawner.

Etymology

The name honours the Irish naturalist Robert Ball.

References

{{Taxonbar, from=Q13429855 Actiniidae Animals described in 1851