Living Protozoans & Microfossils   

Station Location: Outdoor Exhibit Area Trail, GPS Coordinates: 38°56’50.62”N, 76°13’51.63”W
[Go to List of Tour Stations] [Back to Station 12] [Foward to Station 14]



  • Domain: Eukaryota
  • Kingdom: Protista
  • Phylum: Retaria
  • Subphylum: Foraminifera

Forams are amoeboid protists that are commonly classified in the phylum Retaria, subphylum Foraminfera, although the taxonomy of the forams is complicated and fluid.  Forams are typically shelled, and the shells are called “tests”.  The tests are typically chambered, with openings connecting the chambers.  The Foraminfera are grouped according to their types of shells which are usually composed of calcite formed in various manners.  The shells may also be composed of whatever material is nearby (these are called “agglutinated” structures).  While many of the Foraminfera are small (approximately 0.1 mm), some species can grow to 20 centimeters long.  The larger species often “farm” single-celled algae withing their shells.  Most species, though, consume bacteria and phytoplankton, using cellular extensions called reticulopodia to capture their prey.  Reticulopodia also assist their motility.  There are over 10,000 identified species of living forams, most of which are benthic.  Forams are an important source of food for other aquatic organisms, including snails and fish.  They are found in every type of aqueous environment, and are extremely abundant in certain locales, existing in concentrations in the tens of thousands per square foot of ocean bottom.

In addition to the estimated 10,000 living species of forams, paleobiologists have identified over 40,000 foram species in the fossil record. Foraminifera probably evolved during the Cambrian Period (541-485 million years ago), with an abundance of well-characterized fossils existing from all of the periods of the Paleozoic and Cenozoic Eras.  This record has been extremely important for paleontology, since it provides a reliable means of determining the geologic age of the matrix in which they’re found, and for constructing evolutionary timelines for organisms living during these ancient periods.



Learn More:

UMCP Berkeley: Introduction to the Foraminifera

World Foraminifera Database

INTRODUCTION: Foraminiferal repopulation of the Late Eocene Chesapeake Bay Impact Crater


Notes & References:

Photo attribution: (distributable under Creative Commons license)