Xenophyophorea is a clade of foraminiferans. Members of this class are multinucleate unicellular organisms found on the ocean floor throughout the world's oceans, at depths of 500 to 10,600 metres. They are a kind of foraminiferan that extract minerals from their surroundings and use them to form an exoskeleton known as a test.
Foraminifera are single-celled organisms, members of a phylum or class of Cercozoan protists characterized by streaming granular ectoplasm for catching food and other uses; and commonly an external shell of diverse forms and materials. Tests of chitin are believed to be the most primitive type. Most foraminifera are marine, the majority of which live on or within the seafloor sediment, while a smaller number float in the water column at various depths, which belong to the suborder Globigerinina. Fewer are known from freshwater or brackish conditions, and some very few (nonaquatic) soil species have been identified through molecular analysis of small subunit ribosomal DNA.
The Rhizaria are a diverse and species-rich supergroup of mostly unicellular eukaryotes. Except for the Chlorarachniophytes and three species in the genus Paulinella in the phylum Cercozoa, they are all non-photosynthethic, but many foraminifera and radiolaria have a symbiotic relationship with unicellular algae. A multicellular form, Guttulinopsis vulgaris, a cellular slime mold, has been described. This group was used by Cavalier-Smith in 2002, although the term "Rhizaria" had been long used for clades within the currently recognized taxon. Being described mainly from rDNA sequences, they vary considerably in form, having no clear morphological distinctive characters (synapomorphies), but for the most part they are amoeboids with filose, reticulose, or microtubule-supported pseudopods. In the absence of an apomorphy, the group is ill-defined, and its composition has been very fluid. Some Rhizaria possess mineral exoskeletons, which are in different clades within Rhizaria made out of opal, celestite, or calcite. Certain species can attain sizes of more than a centimeter with some species being able to form cylindrical colonies approximately 1 cm in diameter and greater than 1 m in length. They feed by capturing and engulfing prey with the extensions of their pseudopodia; forms that are symbiotic with unicellular algae contribute significantly to the total primary production of the ocean.
Phaeodarea or Phaeodaria is a group of amoeboid cercozoan organisms. They are traditionally considered radiolarians, but in molecular trees do not appear to be close relatives of the other groups, and are instead placed among the Cercozoa. They are distinguished by the structure of their central capsule and by the presence of a phaeodium, an aggregate of waste particles within the cell.
Lobosa is a taxonomic group of amoebae in the phylum Amoebozoa. Most lobosans possess broad, bluntly rounded pseudopods, although one genus in the group, the recently discovered Sapocribrum, has slender and threadlike (filose) pseudopodia. In current classification schemes, Lobosa is a subphylum, composed mainly of amoebae that have lobose pseudopods but lack cilia or flagella.
Gromia is a genus of protists, closely related to foraminifera, which inhabit marine and freshwater environments. It is the only genus of the family Gromiidae. Gromia are ameboid, producing filose pseudopodia that extend out from the cell's proteinaceous test through a gap enclosed by the cell's oral capsule. The test, a shell made up of protein that encloses the cytoplasm, is made up of several layers of membrane, which resemble honeycombs in shape — a defining character of this genus.
The Soritoidea are a group of miliolid benthic foraminifera with porcellaneous tests. They take on a variety of growth forms but typically have many chambers. Some soritids can grow over a centimeter across, huge for protists. All Soritoidea keep algal endosymbionts, which may be what allows them to achieve such large sizes. Some species have red algal symbionts, some have green algal symbionts, and others dinoflagellate symbionts. These larger symbiont-bearing foraminifera are typically found in the oligotrophic waters of the tropics.
Bodo saltans is a free-living nonparasitic species of kinetoplastid flagellated phagotrophic protozoa that feed on bacteria. Bodo saltans cells have been reported in freshwater and marine environments.
In biology, a test is the hard shell of some spherical marine animals and protists, notably sea urchins and microorganisms such as testate foraminiferans, radiolarians, and testate amoebae. The term is also applied to the covering of scale insects. The related Latin term testa is used for the hard seed coat of plant seeds.
Carterinida is an order of multi-chambered foraminifera within the Globothalamea. Members of this order form hard tests out of thin calcite rods known as spicules, which are held together by a proteinaceous matrix. As of August 2023, the order contains a single family, Carterinidae.
Elphidium williamsoni is a species of foraminiferans belonging to the family Elphidiidae. Elphidium williamsoni is found in abundance around the coasts of the UK, predominantly in the lower end of the coast.
Reticulomyxa is a monospecific genus of freshwater foraminiferans. The type species is the unicellular Reticulomyxa filosa. It is found in freshwater environments as well as moist environments, like decomposing matter and damp soils. The heterotrophic naked foraminiferan can feed on microbes as well has larger organisms and is able to be sustained in culture by supplemented nutrients such as wheat germ and oats. The large, multinucleate foraminferan is characteristic for its lack of test and named for the network of connecting pseudopodia surrounding its central body mass. The organism has unique bidirectional cytoplasmic streaming throughout the anastomosing pseudopodia that is some of the fastest reported organelle transport observed. Reticulomyxa was first described in 1949 and is commonly used as a model organism for the unique transport of organelles throughout the cytoplasm of pseudopodia by cytoskeletal mechanisms. Only asexual reproduction of this genus has been observed in culture, but the genome possesses genes related to meiosis suggesting it is capable of sexually reproductive life stages.
Tubothalamea is a taxonomic class established for foraminiferans with tubular chambers. Includes the porcelaceous and agglutinated Miliolida and the monocrystalline and agglutinated Spirillinida. It is one of two classes of multichambered foraminifera based on SSU rDNA molecular studies with consideration of major morphological trands, the other being the Globothalamea.
Globothalamea comprises a class of multichambered foraminifera based in part on SSU rDNA evidence; the other is Tubothalamea.
Stercomata are extracellular pellets of waste material produced by some groups of foraminiferans, including xenophyophoreans and komokiaceans, Gromia, and testate amoebae. The pellets are ovoid (egg-shaped), brownish in color, and on average measure from 10-20 µm in length. Stercomata are composed of small mineral grains and undigested waste products held together by strands of glycosaminoglycans.
Ammonia is a genus of marine foraminifers. It is one of the most abundant foraminifer genera worldwide and occurs in sheltered and shallow marine intertidal environments, sometimes in brackish waters.
Occultammina is a genus of xenophyophorean foraminifera known from the Atlantic and Pacific oceans. It is notable for being the first known infaunal xenophyophore as well as for being a possible identity for the enigmatic trace fossil Paleodictyon.
Many protists have protective shells or tests, usually made from silica (glass) or calcium carbonate (chalk). Protists are a diverse group of eukaryote organisms that are not plants, animals, or fungi. They are typically microscopic unicellular organisms that live in water or moist environments.
Foraminiferal tests are the tests of Foraminifera.
A protist is any eukaryotic organism that is not an animal, plant, or fungus. While it is likely that protists share a common ancestor, the last eukaryotic common ancestor, the exclusion of other eukaryotes means that protists do not form a natural group, or clade. Therefore, some protists may be more closely related to animals, plants, or fungi than they are to other protists. However, like algae, invertebrates and protozoans, the grouping is used for convenience.
