Foraminifera Marcelle BouDagher-Fadel

HOW TO RECOGNIZE A PLANKTONIC FORAMINIFERA By its simplicity Lacks the additional skeletal Structures characteristics of Benthic foraminifera No plugs No pillars No canal system No internal structure, or tooth-plates in thin sections or solid, lips sticking out or in from the simple aperture Aperture simple Although the aperture may be modified exteriorly by apertural lips, portici, tegillum….)

Planktic (planktonic) foraminifera can permanently float or drift in the water column. They are widespread and have had rapidly evolving lineages They are very abundant in inner to outer neritic sediments

Wall texture of planktonic foraminifera Spinose cancellate Globigernoides smooth Cancellate - spinose muricate Pulleniatina Hastigerina Morozovella

Appearance of first planktonic foraminifera

keel elongate chamber extensions biserial Muricae fusing Large perforations wide umbilicus

Globigerinoides Globorotalia spines keel Dorsal view Peripheral view Umbilical viewDorsal apertures Umbilical view aperture

Planktic/Benthic Paleodepth: planktic forams not in coastal zones (neritic), P/B >>100 in open ocean Dissolution: planktic forams fragment, dissolve before benthics; deep-sea floor low P/B values indicate depth below lysocline Surface productivity: more difficult, but at higher food supply productivity (or: in shallower waters) more benthic foraminifera

BouDagher-Fadel, M.K., Banner, F.T. and Whittaker, J.E., Early Evolutionary History of Planktonic Foraminifera, British Micropalaeontological Society Publication Series, Chapman and Hall Publishers, pp 269.Early Evolutionary History of Planktonic Foraminifera Haynes, J.R., Foraminifera. MacMillan, London, pp 433.