Early Palaeocene Parvularugeoglobigerina and late Eocene Praetenuitella; does evolutionary convergence imply similar habitat?

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doi: 10.1144/jm.14.2.119
Author(s): Li, Qianyu; McGowran, B.; Boersma, A.
Author Affiliation(s): Primary:
University of Adelaide, Department of Geology and Geophysics, Adelaide, South Aust., Australia
Other:
Microclimates, United States
Volume Title: Journal of Micropalaeontology
Source: Journal of Micropalaeontology, Vol.14 (Part 2), p.119-134. Publisher: British Micropalaeontological Society, London, United Kingdom. ISSN: 0262-821X
Note: In English. 57 refs.; illus., incl. 4 plates, 1 table, charts
Summary: The species of the earliest Palaeocene planktonic foraminiferal genus Parvularugoglobigerina are characterized by a small test with a smooth, microperforate wall and an elongate aperture. Pore-mound structures may occur on some specimens, while the coiling mode varies from high- to low-trochospiral. Four morphotypes are distinct enough to be recognized as species: P. eugubina (Luterbacher & Premoli Silva) is low spiral and multichambered and P. perexigua n. sp. is four-chambered; P. fodina (Blow) has a Globigerina bulloides-type morphology and P. alticonusa n. sp. has a high trochospire. With the exception of the high spire, this general morphology is repeated in late Eocene forms classified as Praetenuitella: P. insolita (Jenkins), P. patefacta Li, and other associated forms. The two groups acquired their strong similarities - highly distinctive, peculiarly elongated aperture and microperforate walls - through evolutionary convergence, not by being directly related. Stratigraphically they each have a brief occurrence in a geologically significant slice of Palaeogene time: the one during the recovery of ecosystems in the earliest Palaeocene; the other immediately prior to the great cooling and in the time of rapid change known as the Terminal Eocene Event. This study shows that Praetenuitella flourished in eutrophic conditions and that their evolution might have been nutrient-driven. We suggest by morphological pattern analogy that forms of Praetenuitella and Parvulorugoglobigerina reflect similar habitat in their similar form and especially in their aperture.
Year of Publication: 1995
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
ODP Ocean Drilling Program
Key Words: 10 Paleontology, Invertebrate; Anaerobic environment; Biogeography; Biologic evolution; Cenozoic; DSDP Site 152; DSDP Site 577; Deep Sea Drilling Project; Ecosystems; Eocene; Foraminifera; Globigerina; Globigerinacea; Globigerinidae; Habitat; IPOD; Invertebrata; Leg 120; Leg 15; Leg 86; Lower Paleocene; Microfossils; Morphology; Morphotypes; ODP Site 749; Ocean Drilling Program; Paleocene; Paleoecology; Paleoenvironment; Paleogene; Paleotemperature; Parvularugoglobigeri; Planktonic taxa; Praetenuitella; Protista; Quantitative analysis; Range; Rotaliina; Synonymy; Taxonomy; Tertiary; Upper Eocene
Coordinates: N155243 N155243 W0743628 W0743628
N322628 N322632 E1574324 E1574323
S584302 S584301 E0762427 E0762427
Record ID: 1997005678
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