Catalog entries: Globorotalia cerroazulensis possagnoensis
Type images:Distinguishing features: Like T. frontosa but flatter final chamber, giving test a quadrangular shape, also wall more finely perforate, & usually 3 chambers in the final whorl.
NB These concise distinguishing features statements are used in the tables of daughter-taxa to act as quick summaries of the differences between e.g. species of one genus.
Wall type: Weakly cancellate in earlier chambers, becoming smoother with cylindrical pustules in later chambers; tendency to defoliate.
Morphology: Trochospiral, compressed with 3 (rarely 3.5) chambers in the final whorl; chambers inflated, strongly radially compressed and appressed, increasing moderately rapidly in size; dorsal sutures straight or slightly curved, depressed; aperture a broad, low arch in intra-extraumbilical position, sometimes with a thin imperforate lip; umbilicus generally narrow; ventral sutures slightly curved, depressed; strong tendency for dextral coiling.[Pearson et al. 2006]
Size: Holotype length 0.38 mm, breadth 0.31 mm. [Pearson et al. 2006]
Character matrix
test outline: | Lobate | chamber arrangement: | Trochospiral | edge view: | Inequally biconvex | aperture: | Umbilical |
sp chamber shape: | Globular | coiling axis: | Low | periphery: | N/A | aperture border: | Thin lip |
umb chbr shape: | Globular | umbilicus: | Narrow | periph margin shape: | Broadly rounded | accessory apertures: | None |
spiral sutures: | Moderately depressed | umb depth: | Deep | wall texture: | Cancellate | shell porosity: | Finely Perforate: 1-2.5µm |
umbilical or test sutures: | Moderately depressed | final-whorl chambers: | 3.0-3.5 | N.B. These characters are used for advanced search. N/A - not applicable |
Geographic distribution: Cosmopolitan; possibly most common in northern mid-latitudes. [Pearson et al. 2006]
Aze et al. 2011 summary: Cosmopolitan; based on Pearson et al. (2006)
Isotope paleobiology: Poore and Matthews (1984) recorded this species as having relatively negative oxygen isotope ratios indicating a shallow water habitat. On the other hand, Pearson and others (2001) recorded a deep, thermocline signal. [Pearson et al. 2006]
Aze et al. 2011 ecogroup 2 - Open ocean mixed-layer tropical/subtropical, without symbionts. Based on δ13C lighter than species with symbionts; also with relatively light δ18O. Sources cited by Aze et al. 2011 (appendix S3): Poore & Matthews (1984)
Phylogenetic relations: Evolved from Turborotalia frontosa, according to Toumarkine and Bolli (1970). [Pearson et al. 2006]
Most likely ancestor: Turborotalia frontosa - at confidence level 4 (out of 5). Data source: Pearson et al. (2006), fig 15.1.
Geological Range:
Notes: Middle Eocene, middle Zone E9 to upper Zone E11 (Toumarkine and Bolli, 1970). [Pearson et al. 2006]
Last occurrence (top): in upper part of E11 zone (80% up, 40.7Ma, in Bartonian stage). Data source: Pearson et al. (2006), fig. 15.1
First occurrence (base): in mid part of E9 zone (50% up, 43.5Ma, in Lutetian stage). Data source: Pearson et al. (2006), fig. 15.1
Plot of occurrence data:
Primary source for this page: Pearson et al. 2006 - Eocene Atlas, chap. 15, p. 456
Pearson, P. N., Premec-Fucek, V. & Premoli Silva, I. (2006b). Taxonomy, biostratigraphy, and phylogeny of Eocene Turborotalia. In, Pearson, P. N., Olsson, R. K., Hemleben, C., Huber, B. T. & Berggren, W. A. (eds) Atlas of Eocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication. 41(Chap 15): 433-460. gs V O Poag, C. W. & Commeau, J. A. (1995). Paleocene to middle Miocene planktic foraminifera of the southwestern Salisbury Embayment, Virginia and Maryland: Biostratigraphy, allostratigraphy, and sequence stratigraphy. Journal of Foraminiferal Research. 25: 134-155. gs Poore, R. Z. & Bybell, L. M. (1988). Eocene to Miocene biostratigraphy of New Jersey Core ACGS #4: Implications for regional stratigraphy. U.S. Geological Survey Bulletin. 1829: 1-41. gs Poore, R. Z. & Matthews, R. K. (1984). Oxygen isotope ranking of late Eocene and Oligocene planktonic foraminifers: implications for Oligocene sea-surface temperatures and global ice-volume. Marine Micropaleontology. 9: 111-134. gs Toumarkine, M. & Bolli, H. M. (1970). Evolution de Globorotalia cerroazulensis (Cole) dans l'Eocene moyen et superieur de Possagno (Italie). Revue de Micropaléontologie. 13(3): 131-145. gs Toumarkine, M. & Luterbacher, H. (1985). Paleocene and Eocene planktic foraminifera. In, Bolli, H. M., Saunders, J. B. & Perch-Neilsen, K. (eds) Plankton Stratigraphy. Cambridge Univ. Press, Cambridge 87-154. gs Toumarkine, M. (1975). Middle and Late Eocene planktonic foraminifera from the northwestern Pacific Ocean: Leg 32 of the Deep Sea Drilling Project. Initial Reports of the Deep Sea Drilling Project. 32: 735-751. gsReferences:
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Turborotalia possagnoensis compiled by the pforams@mikrotax project team viewed: 18-1-2021
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