Skip to main content Accessibility help

Phyletic gradualism in a Late Cenozoic planktonic foraminiferal lineage; DSDP Site 284, southwest Pacific

  • Björn A. Malmgren (a1) and James P. Kennett (a2)


Shape measurements have been made on planktonic foraminifera from a South Pacific Late Miocene to Recent temperate evolutionary lineage (Globorotalia conoidea through intermediate forms to G. inflata in DSDP Site 284). The sampling interval is about 0.1 Myr over nearly 8 Myr. Gradual evolution (phyletic gradualism) clearly occurs in all but one measured parameter. No clear evidence exists for abrupt evolutionary steps (punctuated equilibria) within the bioseries. If they occur, they are the exception rather than the rule. The number of chambers in the final whorl decreases almost linearly, despite known paleoceanographic oscillations within the temperate water mass. Mean size and apertural shape variations seem to correlate with paleoceanographic change. It is speculated that certain major morphological changes that took place within this evolutionary bioseries (i.e. loss of keel, rounding of periphery) developed in response to a major latest Miocene cooling, associated with instability in the water column and resulting adjustments of the test structure to water density changes. Changes exhibited in shape measurements may offer a precise method of stratigraphic correlation between temperate South Pacific Late Cenozoic sequences. Four species and two subspecies, long recognized to form the basis of this lineage, are redefined biometrically.



Hide All
Bender, M. L. and Keigwin, L. D. Jr. 1979. Speculations about the upper Miocene change in abyssal Pacific dissolved bicarbonate δ13C. Earth Planet. Sci. Lett. 45:383393.
Berger, W. H. 1969. Planktonic foraminifera: basic morphology and ecologic implications. J. Paleontol. 43:13691382.
Berggren, W. A. 1977. Late Neogene planktonic foraminiferal biostratigraphy of the Rio Grande Rise (South Atlantic). Mar. Micropaleontol. 2:265313.
Campbell, N. A. and Reyment, R. A. 1978. Discriminant analysis of a Cretaceous foraminifer using shrunken estimators. Math. Geol. 10:347359.
Eldredge, N. and Gould, S. J. 1972. Punctuated equilibria: an alternative to phyletic gradualism. pp. 82115. In: Schopf, T. J. M., ed. Models in Paleobiology. Freeman, Cooper and Co.; San Francisco, California.
Gould, S. J. and Eldredge, N. 1977. Punctuated equilibria: the tempo and mode of evolution reconsidered. Paleobiology. 3:115151.
Haldane, J. B. S. 1949. Suggestions as to quantitative measurement of rates of evolution. Evolution. 3:5156.
Hallam, A. 1978. How rare is phyletic gradualism and what is its evolutionary significance? Evidence from Jurassic bivalves. Paleobiology. 4:1625.
Hsu, K. J., Cita, M. B., and Ryan, W. B. F. 1973. The origin of the Mediterranean evaporites. In: Ryan, W. B. F., K. J. Hsu, et al., eds. Initial Reports of the Deep Sea Drilling Project. 13:12031231. U.S. Gov. Printing Office; Washington, D.C.
Jenkins, D. G. 1967. Planktonic foraminiferal zones and new taxa from the lower Miocene to the Pleistocene of New Zealand. New Zealand J. Geol. Geophys. 10:10641078.
Keigwin, L. D. Jr., Bender, M. L., and Kennett, J. P. 1979. Thermal structure of the deep Pacific Ocean in the Early Pliocene. Science. 205:13861388.
Keller, G. 1978. Late Neogene biostratigraphy and paleoceanography of DSDP Site 310 Central North Pacific and correlation with the southwest Pacific. Mar. Micropaleontol. 3:97119.
Kennett, J. P. 1966. The Globorotalia crassaformis bioseries in north Westland and Marlborough, New Zealand. Micropaleontology. 12:235245.
Kennett, J. P. 1973. Middle and Late Cenozoic planktonic foraminiferal biostratigraphy of the southwest Pacific—DSDP Leg 21. In: Burns, R. E., J. E. Andrews, et al., eds. Initial Reports of the Deep Sea Drilling Project. 21:575639. U.S. Gov. Printing Office; Washington, D.C.
Kennett, J. P. 1976. Phenotypic variation in some Recent and Late Cenozoic planktonic foraminifera. pp. 111170. In: Hedley, R. H. and Adams, C. G., eds. Foraminifera. Vol. 2. Academic Press; London.
Kennett, J. P. 1978. The development of planktonic biogeography in the southern ocean during the Cenozoic. Mar. Micropaleontol. 3:301345.
Kennett, J. P., Watkins, N. D., and Vella, P. 1971. Paleomagnetic chronology of Pliocene–early Pleistocene climates and the Plio-Pleistocene boundary in New Zealand. Science. 171:276279.
Kennett, J. P. and Watkins, N. D. 1974. Late Miocene–early Pliocene paleomagnetic stratigraphy, paleoclimatology, and biostratigraphy in New Zealand. Geol. Soc. Am. Bull. 85:13851398.
Kennett, J. P. and Vella, P. 1975. Late Cenozoic planktonic foraminifera and paleoceanography at DSDP Site 284 in the cool subtropical South Pacific. In: Kennett, J. P., Houtz, R. E., et al., eds. Initial Reports of the Deep Sea Drilling Project. 24:769799. U.S. Gov. Printing Office; Washington, D.C.
Loutit, T. S. and Kennett, J. P. 1979. Application of carbon isotope stratigraphy to Late Miocene shallow marine sediments, New Zealand. Science. 204:11961199.
Poore, R. Z. and Berggren, W. A. 1975. Late Cenozoic planktonic foraminiferal biostratigraphy and paleoclimatology of Hatton-Rockall Basin, DSDP Site 116. J. Foram. Res. 5:270293.
Ryan, W. B. F., Cita, M. B., Dreyfus Rawson, M., Burckle, L. H., and Saito, T. 1974. A paleomagnetic assignment of Neogene Stage boundaries and the development of isochronous datum planes between the Mediterranean, the Pacific and Indian Oceans in order to investigate the response of the world ocean to the Mediterranean “salinity crisis.” Rev. Ital. Paleontol. 80:631688.
Scott, G. H. 1973. Ontogeny and shape in Globorotalia menardii. J. Foram. Res. 3:142146.
Scott, G. H. 1979. The late Miocene to early Pliocene history of the Globorotalia miozea plexus from Blind River, New Zealand. Mar. Micropaleontol. 4:341361.
Scott, G. H. 1980. Globorotalia inflata lineage and G. crassaformis from Blind River, New Zealand: recognition, relationship, and use in latest Miocene–Early Pliocene biostratigraphy. N.Z. J. Geol. Geophys., in press.
Vincent, E., Killingley, J. S., and Berger, W. H. 1980. The magnetic epoch—6 carbon shift: a change in the oceans 13C/12C ratio 6.2 million years ago. Mar. Micropaleontol. 5:185203.


Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed