''Ellobiopsis'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

unicellular A unicellular organism, also known as a single-celled organism, is an organism that consists of a single cell, unlike a multicellular organism that consists of multiple cells. Organisms fall into two general categories: prokaryotic organisms and ...

ectoparasitic Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...

eukaryotes causing disease in crustaceans. This genus is widespread and has been found infecting copepods from both marine and freshwater ecosystems. parasitism has been seen to interfere with fertility in both sexes of copepods.

Taxonomy and History

The ''Ellobiopsis''

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

, ''Ellobiopsis chattoni,'' was first described in 1910 by Caullery after being isolated from an infected copepod found in the

Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ea ...

. ''Ellobiopsis'' was first classified as a dinoflagellate, but observation of a

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...

forming organelle concluded that the ''Ellobiopsis'' was not a part of this group.

Phylogeny A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spe ...

based on small subunit (SSU) ribosomal DNA places ''Ellobiopsis'' in the Alveolata. In the family Ellobiopsidae, the most closely related genus is ''Thalassomyces''. Three

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

have been defined in this genus: ''Ellobiopsis chattoni'' Caullery (1910), ''Ellobiopsis elongata'' Steuer (1932) ''and Ellobiopsis fagei'' Hovasse (1951). These species are characterized by morphology of their reproductive structures and their ability to infect species specific hosts.

Description

Morphology

During dispersal, unflagellated spores of ''Ellobiopsis'' land on the surface of potential hosts. Once in contact with a host, the cell body of the organism grows and takes on an oval shape. A rhizoid pierces the host cuticle to root the parasite in the copepod tissue. The cell body constricts in the center and differentiate into trophomere and gonomere, proximal and distal to the host body. The cell forms a conical shape. The number of gonomeres is distinguishes species. The cell body has been seen to grows to a length of 700 µm and a width of 350 µm.

Life cycle

The

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...

life cycle of ''Ellobiopsis chattoni'' begins with a spore that lands on the surface of a host appendage. A stalk attaches the parasite to the host and it uses an organelle for penetration, called a rhizoid, of the cuticle and to root itself in the host tissue. As the cell grows the root is used for absorption, causing damaging to the local host tissue. Once established at a specific size, approximately 400 µm, the cell body begins to partition itself in half. The half not attached to the host becomes the gonomere and the half attached to the host is named the trophomere. As the gonomere and trophomere partitioning continues to partition, the spore begins to form in the gonomere and it takes on a granulated texture. The pre-spores are released from the reproductive body and form spores for dispersal to the next host.

Host records

* ''E. chattonii'' — '' Acartia clausi'', '' Calanus helgolandica'', ''

Calanus finmarchicus ''Calanus finmarchicus'' is a species of copepods and a part of zooplankton, which is found in enormous amounts in the northern Atlantic Ocean. Distribution and ecology ''Calanus finmarchicus'' is most commonly found in the North Sea and the N ...

'', ''

Centropages typicus ''Centropages'' is a genus of copepods in the family Centropagidae with 34 known marine species. Species * ''Centropages abdominalis'' Sato, 1913 * ''Centropages aucklandicus'' Krämer, 1895 * ''Centropages bradyi'' Wheeler, 1900 * ''Ce ...

'', '' Clausocalanus arcuicornis'', '' Ctenocalanus vanus'', '' Euchaeta marina'', '' Euchaeta wolfendeni'', ''

Metridia longa ''Metridia longa'' is a copepod found in the Arctic, the north Atlantic, the Pacific, and surrounding waters. The female has an average length of about , and the males have an average length of about . Description ''M. longa'' females have an ...

'', '' Pleuromamma gracilis'', '' Pleuromamma borealis'', ''

Portunus pelagicus ''Portunus pelagicus'', also known as the flower crab, blue crab, blue swimmer crab, blue manna crab or sand crab, ''rajungan'' in Indonesian, and ''alimasag'' in Tagalog, Kapampangan, and Pangasinan, is a large crab found in the intertidal estua ...

'', '' Pseudocalanus elongatus'', ''

Pseudocalanus minutus ''Pseudocalanus minutus'' is a small copepod found in the Arctic Ocean and surrounding waters. Description A small copepod, the female is generally between , and the male typically between in length. Distribution ''P. minutus'' is found primar ...

'', '' Undinula vulgaris'' * ''E. elongata'' — '' Clausocalanus arcuicornis'', '' Ctenocalanus vanus'', '' Cosmocalanus darwini'', '' Euchaeta marina'', '' Gaetanus antarcticus'', '' Gaetanus curvicornis'', '' Penaeopsis retacuta'' * ''E. fagei'' — '' Clausocalanus arcuicornis''

References

{{Taxonbar, from=Q5366096 Alveolata genera Parasitic alveolates