Description
- Fossil Foraminefera in Agate
- Late Paleocene~Early Eocene
- Gentenig Region
- Indonesia
- Specimen measures approx. 3 3/8″ wide
Foraminifera are members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm for catching food and other uses; and commonly an external shell (called a “test”) of diverse forms and materials. Tests of chitin (found in some simple genera, and Textularia in particular) are believed to be the most primitive type. Most foraminifera are marine, the majority of which live on or within the seafloor sediment (i.e., are benthic), while a smaller variety float in the water column at various depths (i.e., are planktonic). 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.
Foraminifera typically produce a test, or shell, which can have either one or multiple chambers, some becoming quite elaborate in structure.[4] These shells are commonly made of calcium carbonate (CaCO3) or agglutinated sediment particles. Over 50,000 species are recognized, both living (10,000) and fossil (40,000). They are usually less than 1 mm in size, but some are much larger, the largest species reaching up to 20 cm.
