Zoochlorella (: zoochlorellae) is a colloquial term for any green algae that lives symbiosis within the body of an aquatic invertebrate animal or a .
Classification
Zoochlorellae are various genera belonging to the classes
Chlorophyceae and
Trebouxiophyceae,
historically treated as a single genus
Zoochlorella due to their similar appearance to the genus
Chlorella.
However, this genus was found to be
polyphyletic through molecular phylogeny, and currently considered
nomen rejiciendum. As a consequence, the two species belonging to this obsolete genus have been transferred to different green algal genera.
Origin
The analogy between zoochlorellae and
was used by the botanist Konstantin Mereschkowski in 1905 to argue about the symbiotic origin of chloroplasts (then called 'chromatophores', a term used for completely different structures today).
[Martin W, and Kowallik, K V. 1999, Annotated English translation of Mereschkowsky's 1905 paper 'Über Nature und Ursprung der Chromatophoren im Pflanzenreich'. Eur. J. Phycol., 34: 287-295. Free access to the article ]
Occurrence
In animals
Zoochlorellae are responsible for the
colour of
sea anemone . Zoochlorellae and
zooxanthellae may both be found in the Pacific coast sea anemones
Anthopleura elegantissima and
Anthopleura xanthogrammica.
In protists
Four species of distantly related
testate amoebae have independently evolved into obligate
mixotrophy through the acquisition of zoochlorellae:
Hyalosphenia papilio and
Heleopera sphagni, two lobose amoebae belonging to the order
Arcellinida within the phylum
Amoebozoa;
Archerella flavum, a member of the Labyrinthulomycetes in
Stramenopiles; and
Placocista spinosa, a filose amoeba belonging to the order
Euglyphida within the phylum
Cercozoa.
Various ciliates present zoochlorellae, such as the genera Paramecium, Stentor, Climacostomum, Coleps and Euplotes.
In the centrohelid Acanthocystis turfacea lives a unique zoochlorella species known as Chlorella heliozoae.
