Nummulites

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Nummulites

[′nəm·yə‚līts]
(invertebrate zoology)
A genus of unicellular shelled protozoa of the order Foraminiferida (superfamily Nummulitacea, family Nummulitidae). The discoidal, lenticular, or globular test or shell can reach a diameter of about 5 inches (12 centimeters) and is composed of finely perforate calcium carbonate, it consists of planispirally enrolled whorls of many tiny undivided chambers.

Nummulites

 

a genus of extinct unicellular organisms of the subclass Foraminifera. Remains of Nummulites have been found in Upper Cretaceous and in Paleogene deposits in the tropics and subtropics of Europe, Asia, Africa, and America. Nummulites had a lenticular or discoid shell with a diameter that ranged from 1 to 16 cm. The shell contains many whorls divided by septa into chambers; each new whorl completely overlaps the next older whorl. Nummulites led a benthopelagic mode of life. Aggregates of their shells formed nummulitic limestone, which is used as a building material. Nummulites are important index fossils in the stratigraphy of the Paleogene.

REFERENCE

Osnovy paleontologii: obshchaia chast’: prosteishie. Moscow, 1959.
References in periodicals archive ?
1846): Memoire sur le terrain a Nummulites (Epicretace) des Corbieres et de la Montagne Noire.
ii) Nummulites atacicus: This species was dominantly found in the lower to middle parts of the formation throughout the study area.
Nummulites, Assilina and Discocyclina are mostly present in the open shoal to the offshore part of the carbonate platform.
Las formas grandes de Nummulites y Pseudophragmina presentes en la microfacies 4 son paleoecologicamente un caso especial, ya que se podria tratar de formas adaptadas a un ambiente mas profundo de plataforma externa (Hallock & Glenn, 1986).
Nummulites mamillatus (FICHTEL and MOLL) Nummulites atacicus LEYMERIE 1846
1998) Nummulites fabianii appears first in the Late Eocene (Priabonian) SBZ 19, and has been documented by various workers to range extending to SBZ 20 and there is no evidence of its occurrence in the older or younger strata (Matsumaru and Sarma, 2010; Less et al.
After development step in Middle Eocene, with isotopic changes in [delta]18O, decrease in temperature of Middle-Late Eocene and decrease in carbonate environments which followed by submarine volcanoes ultimately nummulites were extincted.
A diverse age and depth diagnostic foraminiferal fauna that characterizes the topsets of the HST includes Ranikothalia sindensis Ranikothali nuttali Miscellanea miscella Lockhartia Miscellanea stampi Operculina salsa Operculina subsalsa Discocyclina ranikotensis Discocyclina Seunesi Operculina petalensis Assilina spinosa Nummulites lahiri Nummulites thalicus Nummulites pinfoldi Alveolina vredenburgi Alveolina pasticlata Alveolina conradi and Alveolina globula (Fig.
laminose, Nummulites atacicus/dolloti and Orbitolites complanatus.
Biostratigraphical investigations revealed that the limestone is host of a number of biostratigraphically important benthonic larger foraminiferal species belonging to the genera: Nummulites, Assilina, Lockhartia, Alveolina and Opercolina.