The Apicomplexa are a large phylum of parasitic alveolates. Most of them possess a unique form of organelle that comprises a type of plastid called an apicoplast, and an apical complex structure. The organelle is an adaptation that the apicomplexan applies in penetration of a host cell.
The alveolates are a group of protists, considered a major clade and superphylum within Eukarya, and are also called Alveolata.
The parabasalids are a group of flagellated protists within the supergroup Excavata. Most of these eukaryotic organisms form a symbiotic relationship in animals. These include a variety of forms found in the intestines of termites and cockroaches, many of which have symbiotic bacteria that help them digest cellulose in woody plants. Other species within this supergroup are known parasites, and include human pathogens.
Perkinsus is a genus of alveolates in the phylum Perkinsozoa. The genus was erected in 1978 to better treat its type species, Perkinsus marinus, known formerly as Dermocystidium marinum. These are parasitic protozoans that infect molluscs, at least some of which cause disease and mass mortality. P. marinus is the most notorious, causing the disease perkinsosis, or dermo, in wild and farmed oysters.
The gregarines are a group of Apicomplexan alveolates, classified as the Gregarinasina or Gregarinia. The large parasites inhabit the intestines of many invertebrates. They are not found in any vertebrates. However, gregarines are closely related to both Toxoplasma and Plasmodium, which cause toxoplasmosis and malaria, respectively. Both protists use protein complexes similar to those that are formed by the gregarines for gliding motility and invading target cells. This makes them excellent models for studying gliding motility with the goal of developing treatment options for toxoplasmosis and malaria. Thousands of different species of gregarines are expected to be found in insects, and 99% of these gregarines still need to be described. Each insect can be the host of multiple species. One of the most studied gregarines is Gregarina garnhami. In general, gregarines are regarded as very successful parasites, as their hosts are spread over the entire planet.
Agamococcidiorida is an order within the subclass Coccidia of the phylum Apicomplexia. All members of this order are parasitic protozoa.
Colpodella is a genus of alveolates comprising 5 species, and two further possible species: They share all the synapomorphies of apicomplexans, but are free-living, rather than parasitic. Many members of this genus were previously assigned to a different genus - Spiromonas.
Myzozoa is a grouping of specific phyla within Alveolata, that either feed through myzocytosis, or were ancestrally capable of feeding through myzocytosis.
Amoebophyra is a genus of dinoflagellates. Amoebophyra is a syndinian parasite that infects free-living dinoflagellates that are attributed to a single species by using several host-specific parasites. It acts as "biological control agents for red tides and in defining species of Amoebophrya." Researchers have found a correlation between a large amount of host specify and the impact host parasites may have on other organisms. Due to the host specificity found in each strain of Amoebophrya's physical makeup, further studies need to be tested to determine whether the Amoebophrya can act as a control against harmful algal blooms.
Percolomonas is a genus of free-living flagellate Heteroloboseans, forming a clade with Stephanopogon.
Climacostomum is a genus of unicellular ciliates, belonging to the class Heterotrichea.
Mesodinium chamaeleon is a ciliate of the genus Mesodinium. It is known for being able to consume and maintain algae endosymbiotically for days before digesting the algae. It has the ability to eat red and green algae, and afterwards using the chlorophyll granules from the algae to generate energy, turning itself from being a heterotroph into an autotroph. The species was discovered in January 2012 outside the coast of Nivå, Denmark by professor Øjvind Moestrup.
Defretinella is a genus of parasitic alveolates of the phylum Apicomplexa.
The Archigregarinorida are an order of parasitic alveolates in the phylum Apicomplexa. Species in this order infect marine invertebrates — usually annelids, ascidians, hemichordates and sipunculids.
Pseudotrichomonas keilini is a species of excavates that was discovered by Ann Bishop in 1939.
Veloxidium is a genus of parasitic alveolates in the phylum Apicomplexa. Species in this genus infect marine invertebrates.
The Platyproteum are a genus of parasitic alveolates in the phylum Apicomplexa. Species in this genus infect marine invertebrates.
The genus Aplanochytrium is part of the class Labyrinthulomycetes. It is a sister genus of Labyrinthula and thraustochytrids. The major characteristic of all three genera is the production of an extension of the plasma membrane and the ectoplasm called the ectoplasmic net, but its use is different in each genera. Aplanochytrium cells are not embedded in the ectoplasmic net but can move by gliding on the ectoplasmic threads.
Tracheloraphis is a genus of ciliates in the family Trachelocercidae.
Gregarina garnhami is a eukaryotic unicellular organism belonging to the Apicomplexa described in 1956 by Canning as a parasite found in several locusts, such as the desert locust, African migratory locust, and Egyptian locust. Especially, the desert locust is the host for this species, as up to 100% of animals can become infected. An estimated thousands of different species of gregarines can be in insects and 99% of these gregarines still need to be described. Each insect is said to host multiple species. A remarkable feature of G. garnhami is its auto-fluorescence.
