Turborotalia cunialensis


Classification: pf_cenozoic -> Globanomalinidae -> Turborotalia -> Turborotalia cunialensis
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 cunialensis (Toumarkine & Bolli 1970)
Rank: Species
Basionym: Globorotalia cerroazulensis subsp. cunialensis Toumarkine & Bolli, 1970
Synonyms:
Taxonomic discussion: Turborotalia cunialensis, as strictly defined, is very rare, although specimens of T. cocoaensis that show some transition towards it, either in having a moderately acute periphery or an imperforate band (e.g., Pl. 15.4, Fig. 17) are more common. Toumarkine and Luterbacher (1985) attributed its rarity to its tendency to dissolve more easily than other species of Turborotalia, but this has yet to be demonstrated. Possibly T. cunialensis was more restricted to tropical latitudes than the other species. [Pearson et al. 2006]

Catalog entries: Globorotalia cerroazulensis cunialensis

Type images:

Distinguishing features: Like T. cocoaensis but more acute periphery to final chamber, and biconvex morphology.

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 cunialensis is distinguished from T. cocoaensis by its even more acute periphery to the final chamber as seen in edge view, and the biconvex morphology. These characters, rather than the presence or absence of a keel, are most reliable in distinguishing the morphospecies. [Pearson et al. 2006]

Wall type: Smooth, normal perforate; tendency to defoliate (e.g., Snyder and Waters, 1985). [Pearson et al. 2006]

Test morphology: Low trochospiral, dorsoventrally strongly compressed biconvex test with 4-5 chambers in the final whorl; most specimens show imperforate keel around periphery, which can be distinctly raised; chambers appressed and embracing, wedge-shaped in ventral aspect and increasing moderately in size; final chamber distinctly acute (<40o) at periphery in edge view; dorsal sutures strongly curved, flat or raised with imperforate band; aperture a broad arch, sometimes almost circular, in extraumbilical position; umbilicus very narrow; ventral sutures moderately curved, depressed. Strong tendency for sinistral coiling. [Pearson et al. 2006]

Size: Holotype length 0.45 mm. [Pearson et al. 2006]

Character matrix

test outline:Subcircularchamber arrangement:Trochospiraledge view:Equally biconvexaperture:Umbilical-extraumbilical
sp chamber shape:Crescenticcoiling axis:Lowperiphery:Imperforate bandaperture border:N/A
umb chbr shape:Subtriangularumbilicus:Narrowperiph margin shape:Subangularaccessory apertures:None
spiral sutures:Raisedumb depth:Shallowwall texture:Smoothshell porosity:Finely Perforate: 1-2.5µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:4.0-5.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: Cosmopolitan, possibly more restricted to tropical latitudes than T. cerroazulensis. [Pearson et al. 2006]
Aze et al. 2011 summary: Cosmopolitan; based on Pearson et al. (2006)

Isotope paleobiology: No data available [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): this study

Phylogenetic relations: Evolved from Turborotalia cocoaensis in the upper Eocene (Toumarkine and Bolli, 1970). [Pearson et al. 2006]

Most likely ancestor: Turborotalia cocoaensis - at confidence level 4 (out of 5). Data source: Pearson et al. (2006), fig 15.1.

Biostratigraphic distribution

Geological Range:
Notes: Upper Eocene, Zone E16, disappearing just below the Eocene/Oligocene boundary (Toumarkine and Bolli 1970; Coccioni and others, 1988). The apparent diachroneity of the first occurrence of this species is probably related to inconsistencies in recognizing it. [Pearson et al. 2006]
Last occurrence (top): in upper part of E16 zone (80% up, 34.1Ma, in Priabonian stage). Data source: Pearson et al. (2006), fig. 15.1
First occurrence (base): in lower part of E16 zone (30% up, 34.4Ma, in Priabonian 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. 450

References:

Bolli, H. M. (1970). The foraminifera of sites 23-31, leg 4. Initial Reports of the Deep Sea Drilling Project. 4: 577-643. gs

Coccioni, R., Monaco, P., Monechi, S., Nocchi, M. & Parisi, G. (1988). Biostratigraphy of the Eocene-Oligocene boundary at Massignano, (Ancona, Italy). In, Premoli Silva, I. , Coccioni, R. & Montanari, A. (eds) The Eocene-Oligocene Boundary in the Marche-Umbria Basin (Italy). International Subcommission on Paleogene Stratigraphy, Ancona 59-80. gs

Pearson, P. N. & Wade, B. S. (2015). Systematic taxonomy of exceptionally well-preserved planktonic foraminifera from the Eocene/Oligocene boundary of Tanzania. Cushman Foundation for Foraminiferal Research, Special Publication. 45: 1-85. gs

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

Snyder, S. W. & Waters, V. J. (1985). Cenozoic planktonic foraminiferal biostratigraphy of the Goban Spur Region, Deep Sea Drilling Project Leg 80. Initial Reports of the Deep Sea Drilling Project. 80: 439-472. 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. (1978). Planktonic foraminiferal biostratigraphy of the Paleogene of Sites 360 to 364 and the Neogene of Sites 362A, 363 and 364 Leg 40,. Initial Reports of the Deep Sea Drilling Project. 40: 679-721. gs


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

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François

Basionym: Globorotalia cerroazulensis subsp. cunialensis Toumarkine & Bolli, 1970

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Jeremy Young (Tonbridge, UK)

corrected, thanks

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