The family Vampyrellidae is a subgroup of the order
Vampyrellida (or
Aconchulinida) within the
supergroup Rhizaria
The Rhizaria are a diverse and species-rich clade of mostly unicellular eukaryotes. Except for the Chlorarachniophytes and three species in the genus '' Paulinella'' in the phylum Cercozoa, they are all non-photosynthetic, but many Foraminifera ...
.
Based on molecular sequence data, the family currently comprises the genus ''
Vampyrella'', and maybe several other vampyrellid amoebae (e.g. ''Gobiella'').
The cells are naked and characterised by radiating, filose
pseudopodia
A pseudopod or pseudopodium (: pseudopods or pseudopodia) is a temporary arm-like projection of a eukaryotic cell membrane that is emerged in the direction of movement. Filled with cytoplasm, pseudopodia primarily consist of actin filaments and ...
(also referred to as
filopodia
Filopodia (: filopodium) are slender cytoplasmic projections that extend beyond the leading edge of lamellipodia in migrating cells. Within the lamellipodium, actin ribs are known as ''microspikes'', and when they extend beyond the lamellipod ...
) and an orange colouration of the main cell body.
In former times the family Vampyrellidae contained several genera (e.g. ''
Vampyrella'', ''Gobiella'', ''Leptophrys'', ''Platyreta'', ''Theratromyxa'') and was identical with the order
Vampyrellida, also known under the name "Aconchulinida".
However, based on molecular sequence data the family Vampyrellidae was restricted to a subgroup containing only the genus ''
Vampyrella'', and a different family
Leptophryidae was established for the genera ''
Leptophrys'', ''
Platyreta'' and ''
Theratromyxa''.
Characteristics
When free-floating, the cell is spherical and around 30 μm across, with long radially directed filose pseudopods as well as distinctive shorter club-shaped ones, so that it resembles a
heliozoa
Heliozoa, commonly known as sun-animalcules, are microbial eukaryotes (protists) with stiff arms (Pseudopodia#Morphology, axopodia) radiating from their spherical bodies, which are responsible for their common name. The axopodia are microtubule- ...
n. Moving, the cell stretches out and takes a more typical
amoeboid
An amoeba (; less commonly spelled ameba or amœba; : amoebas (less commonly, amebas) or amoebae (amebae) ), often called an amoeboid, is a type of cell or unicellular organism with the ability to alter its shape, primarily by extending and r ...
form, with an obvious distinction between the clear periphery and pseudopods and the greenish interior. In this form it finds its way into
alga
Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular microalgae, suc ...
e cells and feeds on their interiors. At least one genus, Theratromyxa, also feeds on soil nematodes.
Morphology and fine structure of the trophozoites of Theratromyxa weberi (Protozoa: Vampyrellidae) predacious on soil nematodes
/ref> A few other vampyrellids 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 ...
on fungi
A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...
. As such, these vampyrellids can be an important control of parasitic rust fungus
Rusts are fungal plant pathogens of the order Pucciniales (previously known as Uredinales) causing plant fungal diseases.
An estimated 168 rust genera and approximately 7,000 species, more than half of which belong to the genus ''Puccinia'', are ...
of wheat
Wheat is a group of wild and crop domestication, domesticated Poaceae, grasses of the genus ''Triticum'' (). They are Agriculture, cultivated for their cereal grains, which are staple foods around the world. Well-known Taxonomy of wheat, whe ...
and other crops.
Vampyrellids characteristically have mitochondria
A mitochondrion () is an organelle found in the cells of most eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is us ...
with tubular crista
A crista (; : cristae) is a fold in the inner mitochondrial membrane, inner membrane of a mitochondrion. The name is from the Latin for ''crest'' or ''plume'', and it gives the inner membrane its characteristic wrinkled shape, providing a large a ...
e. Together with the nucleariid
The nucleariids, or nucleariid amoebae, are a group of amoebae that compose the sister clade of the fungi. Together, they form the clade Holomycota. They are aquatic organisms found in freshwater and marine habitats, as well as in faeces. They ...
s they include the majority of the naked filose amoebae.
Systematics and phylogeny
Genera and species
There are at least 19 credibly described 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), ...
that are either proved or likely to belong to the family Vampyrellidae, all of them belonging to the genus '' Vampyrella''.
=''Gobiella closterii''
**'' Vampyrella euglenae''
**'' Vampyrella flabellata''
**'' Vampyrella gomphonematis''
**'' Vampyrella helioproteus''
**'' Vampyrella incolor''
**'' Vampyrella inermis''
**'' Vampyrella lateritia''
= ''Amoeba lateritia''
= ''Vampyrella spirogyrae''
**'' Vampyrella mirabilis''
**'' Vampyrella multiformis''
**'' Vampyrella pallida''
= ''Vampyrina pallida''
**'' Vampyrella peritrichophaga''
**'' Vampyrella polyblasta''
**'' Vampyrella radiosa''
**'' Vampyrella soror''
**'' Vampyrella ulothricis''
**'' Vampyrella variabilis''
Phylogenetic tree
The following cladogram depicts the relationships between Vampyrellidae and other vampyrellid families. Of the 19 species, only 2 species of '' Vampyrella'' have been genetically sequenced, which limits the information on the internal relationships of the genus.
References
External links
*
*http://starcentral.mbl.edu/microscope/portal.php?pagetitle=assetfactsheet&imageid=932
*http://tolweb.org/tree?group=The_other_protists&contgroup=Eukaryotes
{{Taxonbar, from=Q917169
Rhizaria families
Taxa named by Friedrich Wilhelm Zopf