''Perkinsus'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

alveolate The alveolates (meaning "pitted like a honeycomb") are a group of protists, considered a major unranked clade or superphylum within Eukaryota. They are currently grouped with the Stramenopiles and Rhizaria among the protists with tubulocristate ...

s in the phylum

Perkinsozoa Perkinsids are single-celled protists that live as intracellular parasites of a variety of other organisms. They are classified as the class Perkinsea within the monotypic phylum Perkinsozoa. It is part of the eukaryotic supergroup Alveolata, ...

. The genus was erected in 1978 to better treat its type species, ''

Perkinsus marinus ''Perkinsus marinus'' is a species of alveolate belonging to the phylum Perkinsozoa.Joseph, S., et al. (2010)The alveolate ''Perkinsus marinus'': biological insights from EST gene discovery.''BMC Genomics'' 11(1), 228. It is similar to a dinofl ...

'', known formerly as ''Dermocystidium marinum''. These are

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The ent ...

protozoa Protozoa (: protozoan or protozoon; alternative plural: protozoans) are a polyphyletic group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic debris. Historically ...

ns that infect

molluscs Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

, 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

oyster Oyster is the common name for a number of different families of salt-water bivalve molluscs that live in marine or brackish habitats. In some species, the valves are highly calcified, and many are somewhat irregular in shape. Many, but no ...

s.Petty, D
''Perkinsus'' Infections of Bivalve Molluscs.
FA178. Fisheries and Aquatic Sciences. Florida Cooperative Extension Service. University of Florida IFAS. 2010.

Description

''Perkinsus'' is a

in the class Perkinsea that is a parasite of bivalve

mollusc Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

s; it displays a number of features typical of the

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 including laterally inserted heterodynamic

flagella A flagellum (; : flagella) (Latin for 'whip' or 'scourge') is a hair-like appendage that protrudes from certain plant and animal sperm cells, from fungal spores ( zoospores), and from a wide range of microorganisms to provide motility. Many pr ...

,. However, it has been settled that ''Perkinsus'' does not belong to the

phylum In biology, a phylum (; : phyla) is a level of classification, or taxonomic rank, that is below Kingdom (biology), kingdom and above Class (biology), class. Traditionally, in botany the term division (taxonomy), division has been used instead ...

Dinoflagellata, but rather into the phylum

, which is the

sister group In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

of dinoflagellates.

Classification

As of 2004, six valid species were in the genus. At least two more have been described since then. Species and common hosts include: *''

Perkinsus andrewsi ''Perkinsus'' is a genus of Alveolata, 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 parasitism, parasitic prot ...

'' on Baltic clam (''Macoma balthica'') *''

Perkinsus beihaiensis ''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 mol ...

'' on the oysters ''

Magallana hongkongensis The Hong Kong oyster (''Magallana hongkongensis''), is a species of true oyster found in Hong Kong and the mouth of Pearl River in China. The species was uniquely identified by comparing the genetic distances of mitochondrial DNA sequences. The ...

'' and '' M. ariakensis'' *'' Perkinsus chesapeaki'' on

soft-shell clam Soft-shell clams (American English) or Sand gaper (British English/Europe), scientific name ''Mya arenaria'', popularly called "steamers", "softshells", "piss clams", "Ipswich clams", or "Essex clams", are a species of edible saltwater clam, a ...

(''Mya arenaria'') *''

Perkinsus honshuensis ''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 mol ...

'' on Manila clam (''Venerupis philippinarum'') *''

'' on

eastern oyster The eastern oyster (''Crassostrea virginica'')—also called the Atlantic oyster, American oyster, or East Coast oyster—is a species of true oyster native to eastern North and South America. Other names in local or culinary use include the We ...

(''Crassostrea virginica'') *''

Perkinsus mediterraneus ''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 mol ...

'' on European flat oyster (''Ostrea edulis'') *''

Perkinsus olseni ''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 mol ...

'' (syn. ''P. atlanticus'') on

blacklip abalone The blacklip abalone, ''Haliotis rubra'', is an Australian species of large, edible sea snail, a marine gastropod mollusk in the family Haliotidae, the abalone.Bouchet, P. (2012). Haliotis rubra Leach, 1814. Accessed through: World Register of M ...

(''Haliotis rubra'') and grooved carpet shell (''Ruditapes decussatus'') *''

Perkinsus qugwadii ''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 mol ...

'' on yesso scallop (''Patinopecten yessoensis'') ''P. andrewsi'' and ''P. chesapeaki'' might be the same species; because the latter was described first, the name ''P. andrewsi'' will be a synonym.

References

External links

*Guiry, M. D. & G. M. Guiry. 2013
''Perkinsus'' Levine, 1978.
AlgaeBase. National University of Ireland, Galway. Accessed 8 September 2013. {{Authority control Perkinsozoa Alveolata genera