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 Fusulinida is an extinct order within the Foraminifera in which the tests are traditionally considered to have been composed of microgranular calcite. Like all forams, they were single-celled organisms. In advanced forms the test wall was differentiated into two or more layers. Loeblich and Tappan, 1988, gives a range from the Lower Silurian to the Upper Permian, with the fusulinid foraminifera going extinct with the Permian–Triassic extinction event. While the latter is true, a more supported projected timespan is from the Mid-Carboniferous period.
The Textulariida are an order of foraminifera that produce agglutinated shells or tests. An agglutinated test is one made of foreign particles glued together with an organic or calcareous cement to form an external shell on the outside of the organism. Commonly, the order had been made up of all species of Foraminifera with these types of shells, but genetic studies indicate these organisms do not form an evolutionary group, and several superfamilies in the order have been moved to the order Allogromiida. The remaining forms are sometimes divided into three orders: the Trochamminida and Lituolida, which have organic cement, and the Textulariida sensu stricto, which use a calcareous cement. All three orders or superfamilies are known as fossils from the Cambrian onwards.
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.
Alveolinidae is a family of spheroidal to fusiform milioline foraminifera with multiple apertures and complex interiors in which chambers are subdivided into chamberlets and subfloors interconnected by passageways. As with all Miliolina, the test wall in alveolinids is porcellaneous and imperforate. In living individuals the pseudopodia emerge through the multiple apertures that line the apertural or leading face of the test.
Miliolacea is one of five superfamilies belonging to the Miliolida,.
Quinqueloculina is a genus of foraminifera in the family Miliolidae.
Miliamellus is a genus of Cenozoic benthic foraminifera with tests made of imperforate opaline silica. It is the only genus in the order Silicoloculinida and the family Silicoloculinidae. It is sometimes referred to by the junior synonym Silicoloculina.
Globulina is a genus of Foraminifera with an ovate to globular test, included in the Polymorphinidae, Notocariacea, that has been extant since the Middle Jurassic (Callovian).
Triloculina is a genus of foraminifera in the order Miliolida, included in the Quinqueloculininae. The test is three, chambers each a half coil in length. Early chambers, at least in the microspheric generation, in quinqueloculinan arrangement, later becoming triloculine with successive chambers added in planes 120 degrees apart. Only the final three chambers are visible externally. The aperture is terminal, at the end of the final chamber, with a bifid tooth in adult forms. As with the entire order, the test is composed of imperforate, porcelaneous calcite.
Sigmoilina is a miliolid genus, referring to the foraminiferal order Miliolida, characterized by an assymmetricall biconvex test formed by strongly overlapping chambers, one-half coil in length, that form a sigmoid (S-shaped) curve in cross section. The strongly overlapping chambers obliterate earlier ones from view resulting in the compressed biloculine appearance, differing from the squat, depressed biloculine form of Pyrgo and Biloculina. The test, as for all Miliolida, is porcelaneous and imperphorate, the terminal aperture, with tooth, the only point of egress and ingress for the animal.
Sigmoilinita is a miliolid genus (Foraminifera) with an ovate to fusiform test that becomes flattened with growth. Chambers are tubular, one-half coil in length, at first added in a sigmoiline (S-shaped) series starting at slightly more than 180° apart. the angle gradually decreasing until the later whorls are planispiral. Chambers are numerous, the wall narrow. imperforate, porcelaneous. The aperture at the end of the final chamber. may have a weakly developed tooth
Triloculinella is a genus of Miliolacean forams with a fusiform to asymmetrically globular test. Inner chambers, one-half coil in length, are crypto-quinqueloculine to quinqueloculine in arrangement; The final three to five visible from the exterior. The aperture is an arch at the end of the final chamber, largely covered by a broad apertural flap, which distinguishes the genus from Triloculina, Quinqueloculina and such, characterized by a more narrow tooth. The wall, as for all miliolids, is calcareous, imperforate, porcelaneous.
Fischerinidae is a foraminiferal family now in the miliolid superfamily Cornuspiracea that comprises genera that can be free or attached, in which the proloculus is followed by an undivided tubular or spreading second chamber. Commonly, especially in free, i.e. unattached, forms the second chamber is looped around in coils. As diagnostic for the Miliolida the test wall is of imperphorate porcelaneous calcite. The aperture, which is the avenue of egress and ingress for the protoplasm, is terminal; can be rounded or slitlike.
Cornuspiracea comprise a superfamily of miliolid forams in which the test may be free or attached, planispiral or trochospiral, evolute or involute, spreading or discoidal. The proloculus, or initial chamber, is followed by undivided spiral passage or enrolled tubular chamber, later may be irregularly coiled, unicoiled, or show zigzag growth pattern and may be distinctly chambered. The test wall is composed of imperforate porcelaneous calcite, a character of the Miliolida
Miliamminana is a subclass of miliolates established by Mikhalevich, 1980 that combines two groups of foraminifers with agglutinated tests. They are the Rzehakinidae which previously were included in the Texulariina in the Treatise on Invertebrate Paleontology although milioline in form, and the milioline Schlumbergerinida which includes genera removed from the Miliolina. The rzehakinids are composed of finely agglutinated material, insoluble in acid, over an organic base. Schlumbergerinids are composed of acid soluble agglutinated material over a porcelenous base. The unifying character is the nature of their coiling in which there are two tubular chambers, or sections, per whorl arranged in various planes and the fact that they are in part all agglutinated.
Miliolana is a subclass established by Saidova, 1981 that comprises porcelaneous members of the Miliolata from the Cornuspirida, Miliolida with agglutinated forms removed to the Miliamminana, and Soritida. Included are both free and attached forms, some coiled with two chambers per whorl arranged in different planes, others that are irregular or have serial chambers, and still others are fusiform with complex interiors, superficially resembling the Fusulinacea. The unifying character is their imperforate porcelaneous tests.
Meandropsinidae is an extinct family of miliolid forams found in Upper Cretaceous (Cenomanian) to middle Paleocene marine sediments.
Charles Schlumberger was a French paleontologist, known for his studies of Foraminifera, both living and fossil species.
Foraminiferal tests are the tests of Foraminifera.
