Discorbacea

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Discorbacea
Temporal range: Middle Triassic–Recent
Scientific classification
(unranked):
SAR
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Phylum:
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Order:
Superfamily:
Discorbacea

Ehrenberg, 1838
Family

see text

Discorbacea, Discorboidea in recent taxonomies, is a superfamily of foraminifera, [1] (testate protists), with a range extending from the Middle Triassic to the present, characterized by chambers arranged in a low trochspiral; an umbilical or interiomarginal aperture, with or without supplementary apertures; and a wall structure that is optically radial. [2] [3]

Eight families are currently recognized, further characterized here in. [3]

Two other families were included, the Asterigerinidae and Epistomariidae, which have been removed to the Asterigerinacea. Some now included families such as the Bagginidae were once defined as a subfamily, the Bagginindae, based on the genus Baggina, in the Discorbidae. As a result the discorbid subfamily Discorbine became the present Discorbidae. The Pegidiidae, originally the rotaliitid subfamily Pegidiinae was removed from the Rotaliacea and added to the Discorbacea as a family. Helenina, a genus in the Discorbinae, became the type for its own family, the Heleninidae. Finally the Eponididae was once included in the Orbitoidacea before being made part of the Discorbacea. [2]

Related Research Articles

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Globigerina is a genus of planktonic Foraminifera, in the order of Rotaliida. It has populated the world's oceans since the Middle Jurassic.

The Asterigerinacea is a superfamily of Foraminifera included in the order Rotaliida, proposed by Loeblich and Tappan in 1988.

Abathomphalus is a genus of foraminifera included in the Globotruncanid family.

Globigerinoidea Superfamily of foraminifers

Globigerinoidea is a superfamily of free-living, calcareous, planktonic foraminiferal protists that have lived in the open ocean since the Eocene. It is part of the suborder Globigerinina.

Involutinida is an order of foraminifera included in the Spirillinata found in the fossil record from the early Permian to early Late Cretaceous (Cenomanian).

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.

<i>Cibicides</i> Genus of foraminifers

Cibicides is a genus of cosmopolitan benthic foraminifera known from at least as far back as the Paleocene that extends down to the present.

Discorbis is a genus of benthic Foraminfera, that made its first appearance during the Eocene. Its present distribution is cosmopolitan.

Rosalina is a genus of foraminifera included in the rotaliid family Rosalinidae.

Semirosalina is a genus of foraminifera from the Lower Miocene of New Zealand, related to Rosalina, included in discorbacean family Rosalinidae. The test is a small trochospiral coil of few whorls with a few subglobular chambers per whorl. The test wall is thin and finely perforate. The aperture at the umbilical margin of the apertural face.

Rotorboides is a genus of recent (Holocene) bottom dwelling (benthic) forams from the Atlantic, Pacific and Indian Oceans, related to Rosalina.

Astrononion is a genus of foraminifera in the family Nonionidae, characterized by an evolute planispiral test with radially stellate structures partly covering the sutures on either side. The test is free, bilaterally symmetrical; periphery broadly rounded; chambers distinct, separated by depressed radial sutures, increasing gradually in size, and usually inflated; aperture a low arched opening at the base of the face of the test. The wall is of finely perforate monolamellar granular calcite.

The Planorbulinacea are a superfamily of rotalliid foraminifera that has been extant since the Early Cretaceous (Berriasian), characterized by trochospiral tests, at least in early stage but which later may become uncoiled. The test wall is of perforate hyaline calcite, commonly optically radial in structure, with crystallographic c-axes perpendicular to the surface. The apertural face may be imperforate; the aperture interiomarginal and extraumbilical-umbilical to nearly equatorial in coiled forms, subterminal in uncoiled forms.

Hedbergella is an extinct genus of planktonic foraminifera from the Cretaceous, described by Loeblich and Tappan, 1961, as:

Test free, trochospiral, biconvex, umbilicate, periphery rounded with no indication of keel or poreless margin; chambers globular to ovate; sutures depressed, radial, straight or curved; wall calcareous, finely perforate, radial in structure, surface smooth to hispid or rugose; aperture an interiomarginal, extraumbilical-umbilical arch commonly bordered above by a narrow lip or spatulate flap, ... Includes species otherwise similar to Praeglobotruncana but which lack a keel or poreless margin, hence is regarded as a separate genus rather than as a subgenus of Praeglobotruncana as by Banner and Blow (1959).

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Buccella is a genus of late Cenozoic benthic foraminifera that made its first appearance during the Oligocene and is found living in recent oceans.

The Globoroatioidea constitutes a superfamily of Cenozoic plantonic foraminifera. It is part of the suborder Globigerinina. Globoroatioidea have trochospiral tests with rounded to carinate peripheries, the walls of which are of finely lamellar, perforate, of optically radial calcite, with an inner organic lining. The surface of these tests is smooth, lacking spines, but may be covered with pustules or pitted, and may have one or more large pores at the center. There is a single primary aperture that may be bordered by an imperforate lip, as well as possible supplementary apertures.

Gansserina is a genus of planktonic foraminifera, included in the globigerinid family Globotruncanidae, that had a fairly wide distribution in the Late Cretaceous (Maastrichtian). The type species is Gansserina gansseri.

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.

<i>Amphistegina</i> Genus of single-celled organisms

Amphistegina is a genus of foraminiferal protists included in the Rotaliida with a stritigraphic range extending from the Eocene to recent and a cosmopolitan distribution. The test is an asymmetrically biconvex trochospiral that may be bi-involute or partially evolute on the spiral side. Chambers are numerous, broad. and low, strongly curved back at the periphery to form chamber prolongations. The umbilical side is stellate, like that of Asterigerina, and has a distinct umbilical plug. The wall is calcareous, optically radial; the surface finely perforate and smooth overall. The periphery angular to carinate (keeled); the aperture an interiomarginal slit on the umbilical side, bordered by a lip.

The Planispirillinidae are a family of living Foraminifera and the only one of the Involutinida now living.

References

  1. Loeblich and Tappan,1988. Forminiferal Genera and their Classification Archived 2012-06-16 at the Wayback Machine
  2. 1 2 Loeblick and Tappan,1964. Sarcodina Chiefly "Thecamoebians" and Foraminiferida; Treatise on Invertebrate Paleontology, part C Protista 2
  3. 1 2 Sen Gupta, 2002. Modern Foraminifera . Pub Springer