Turborotalia possagnoensis


Classification: pf_cenozoic -> Globanomalinidae -> Turborotalia -> Turborotalia possagnoensis
Sister taxa: T. cunialensis, T. cocoaensis, T. cerroazulensis, T. pomeroli, T. frontosa, T. ampliapertura, T. increbescens, T. altispiroides, T. possagnoensis, T. sp.,

Taxonomy

Citation: Turborotalia possagnoensis (Toumarkine & Bolli 1970)
Rank: Species
Basionym: Globorotalia cerroazulensis possagnoensis
Synonyms:
Taxonomic discussion: This species was originally described as an evolutionary intermediate between T. frontosa (which has been regarded by some as a subbotinid) and the undisputed turborotaliid species, T. pomeroli. In our experience the morphospecies is quite rare in open ocean settings, although common in specimens from the Possagno area, where unfortunately the material is poorly preserved. We have, however, found well-preserved and closely comparable populations in wells from the Adriatic Sea. We regard possagnoensis as a relatively short-lived offshoot from T. frontosa, rather than an evolutionary intermediate to pomeroli as suggested by Toumarkine and Bolli (1970). [Pearson et al. 2006]

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.
They are being edited as the site is developed and comments on them are especially welcome.

Description


Diagnostic characters: Turborotalia possagnoensis is distinguished from T. frontosa by the flatter final chamber, which gives the test a quadrangular shape, by the more finely perforate wall texture and by generally having three chambers in the final whorl. It is distinguished from T. pomeroli by its more angular periphery, having fewer chambers in the final whorl and smaller size. [Pearson et al. 2006]

Wall type: Weakly cancellate in earlier chambers, becoming smoother with cylindrical pustules in later chambers; tendency to defoliate.

Test 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:Lobatechamber arrangement:Trochospiraledge view:Inequally biconvexaperture:Umbilical
sp chamber shape:Globularcoiling axis:Lowperiphery:N/Aaperture border:Thin lip
umb chbr shape:Globularumbilicus:Narrowperiph margin shape:Broadly roundedaccessory apertures:None
spiral sutures:Moderately depressedumb depth:Deepwall texture:Cancellateshell porosity:Finely Perforate: 1-2.5µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:3.0-3.5 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


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.

Biostratigraphic distribution

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

References:

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

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. gs


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Turborotalia possagnoensis compiled by the pforams@mikrotax project team viewed: 31-3-2020

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