Evolutionary ecology of Globorotalia (Globoconella) (planktic foraminifera)

Author(s): Norris, R. D.; Corfield, R. M.; Cartlidge, J. E.
Author Affiliation(s): Primary:
Woods Hole Oceanographic Institution, Department of Geology and Geophysics, Woods Hole, MA, United States
Other:
Oxford University, United Kingdom
Volume Title: Marine Micropaleontology
Source: Marine Micropaleontology, 23(2), p.121-145. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0377-8398 CODEN: MAMIDH
Note: In English. 77 refs.; illus. incl. 3 tables
Summary: Miocene to Recent species of planktic foraminifera in the Globorotalia(Globoconella) lineage evolved entirely within the thermocline. All species are most abundant within subtropical-temperate watermasses throughout their history. The near stasis in distribution within the thermocline and the subtropical convergence suggests the major morphological changes in Globorotalia(Globoconella) may have occurred through habitat subdivision rather than by vicariant shifts into new watermasses. At the Rio Grande Rise, in the South Atlantic, modern G.inflata is 0.66-0.84per mil more positive for δ18O than the most enriched coexisting Globigerinoides sacculifer and probably grows in the mid thermocline deeper than 325 m. All extinct globoconellid species have mean δ18O ratios 0.5-0.8per mil more positive than Globigerinoides trilobus and G.sacculifer and probably lived within the thermocline as well. Major events in skeletal evolution are poorly correlated with changes in δ18O in this group. These include evolutionary transitions to compressed, smooth-walled tests and acquisition of keels. In addition, morphological reversals from the umbilically-inflated G.conomiozea to biconvex G.pliozea and to unkeeled G.puncticulata occur in the absence of changes in δ18O signature. Instead, the ranges of δ18O between different species almost completely overlap once corrected for temporal changes in δ18O of sea water. Foraminifera morphologies have been widely considered to evolve in response to changes in watermasses or depth habitats. However, the variety of skeletal shapes in the globoconellid lineage apparently are not adaptations to a progressive radiation from the surface mixed layer into deeper waters.
Year of Publication: 1994
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Atlantic Ocean; Biologic evolution; Biozones; C-13/C-12; Carbon; Cenozoic; DSDP Site 516; Deep Sea Drilling Project; Depth; Foraminifera; Globigerinacea; Globoconella; Globorotalia; Globorotaliidae; Habitat; IPOD; Invertebrata; Isotope ratios; Isotopes; Leg 72; Marine environment; Microfossils; Miocene; Morphology; Neogene; O-18/O-16; Oxygen; Paleoecology; Planktonic taxa; Protista; Quaternary; Rio Grande Rise; Rotaliina; South American Atlantic; South Atlantic; Stable isotopes; Subtropical environment; Temperate environment; Tertiary; Thermocline
Coordinates: S301636 S301635 W0351706 W0351707
Record ID: 1994025234
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands