pforams@mikrotax - Turborotalia increbescens pforams@mikrotax - Turborotalia increbescens

Turborotalia increbescens

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


Citation: Turborotalia increbescens (Bandy 1949)
taxonomic rank: Species
Basionym: Globigerina increbescens
Taxonomic discussion:

This species was discussed by Pearson and others (2006b). Like T. ampliapertura it survived the extinction of the rest of the genus in the uppermost Eocene. It is rarer and more sporadic than T. ampliapertura in the Oligocene (e.g., Leckie and others, 1993). [Pearson et al. 2018]

This morphospecies is intermediate in morphology between T. pomeroli and T. ampliapertura and also intergrades with T. cerroazulensis in the lower part of the upper Eocene. The holotype is illustrated in SEM here for the first time (Pl.15.6, Figs. 1-3). Blow and Banner (1962) and Blow (1969, 1979) have remarked upon the tendency of the aperture to become more umbilical in position, producing transitional forms toward the ampliapertura morphospecies. Both T. increbescens and T. ampliapertura survived the extinction of the rest of the genus in the uppermost Eocene.
Globigerina tumbeli Khalilov was viewed by W. A. Berggren (pers. comm.) as part of this study and is placed in questionable synonymy. [Pearson et al. 2006]

Catalog entries: Globigerina increbescens, Globigerina tumbili

Type images:

Distinguishing features:
Parent taxon (Turborotalia): Trochospiral with umbilical-extraumbilical aperture.
Wall smooth pustulose, can be weakly cancellate, & may defoliate.

This taxon: Like T. pomeroli but more compact 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.


“Moderate to high trochospiral, globorotaliform inner whorl, compact and rounded test with 3½-4 chambers in the final whorl. Chambers appressed and embracing, radially compressed and increasing moderately in size. Final chamber commonly radially flattened; in edge view, showing rounded periphery with final chamber arching towards umbilicus. Dorsal sutures curved, depressed. Aperture a very broad arch in an intra-extraumbilical position, often irregular and elongate. An imperforate or pustulose lip is usually visible. Umbilicus usually narrow. Ventral sutures slightly curved, depressed. Usually a strong tendency for sinistral coiling” (Pearson and others, 2006b:454). [Pearson et al. 2018]

Wall type:
High porosity, weakly cancellate and coarsely pustulose, often smooth on final chamber; like other Turborotalia it has a tendency to defoliate. [Pearson et al. 2018]

Holotype length 0.51 mm, breadth 0.47 mm. [Pearson et al. 2018]

Character matrix
test outline:Lobatechamber arrangement:Trochospiraledge view:Equally biconvexaperture:Umbilical-extraumbilical
sp chamber shape:Globularcoiling axis:Moderate-highperiphery:N/Aaperture border:Thin lip
umb chbr shape:Subtriangularumbilicus:Wideperiph margin shape:Broadly roundedaccessory apertures:None
spiral sutures:Weakly depressedumb depth:Deepwall texture:Coarsely pustuloseshell porosity:Finely Perforate: 1-2.5µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:3.5-4 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology

Geographic distribution

Cosmopolitan, more common at low latitudes (Leckie and others, 1993). [Pearson et al. 2018]

Isotope paleobiology
Recorded by Boersma and others (1987) as having relatively negative _18O, possibly indicating a shallow-water habitat. [Pearson et al. 2018]
Aze et al. 2011 ecogroup 2 - Open ocean mixed-layer tropical/subtropical, without symbionts. Based on _13C lighter than species with symbionts; also with relatively light _18O. Sources cited by Aze et al. 2011 (appendix S3): Pearson et al. (2006)

Phylogenetic relations
Evolved from Turborotalia pomeroli in the middle Eocene (Blow and Banner, 1962; Toumarkine and Bolli, 1970). The species is no longer considered the likely ancestor of ampliapertura (see discussion under that species). [Pearson et al. 2018]

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

Biostratigraphic distribution

Geological Range:
Notes: Middle Eocene Zone E13 (Postuma, 1971) to lower part of lower Oligocene Zone O2 (Pearson and Chaisson, 1997). Blow (1979, fig. 53, p. 311) and Leckie and others (1993, p. 118) recorded the highest occurrence as slightly below the topmost Pseudohastigerina and hence in the top of Zone O1; Pearson and Chaisson (1997) recorded it extending to just within (the lowermost of 8 studied samples) Zone O2. [Pearson et al. 2018]
Last occurrence (top): at top of O1 zone (100% up, 32.1Ma, in Rupelian stage). Data source: Pearson et al. (2018), fig. 14.1
First occurrence (base): in mid part of E13 zone (50% up, 39Ma, in Bartonian stage). Data source: Pearson et al. (2006), fig. 15.1

Plot of occurrence data:

Primary source for this page: Pearson et al. 2018 - Olig Atlas chap.14 p.411; Pearson et al. 2006 - Eocene Atlas, chap. 15, p. 453


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Blow, W. H. (1969). Late middle Eocene to Recent planktonic foraminiferal biostratigraphy. In, Bronnimann, P. & Renz, H. H. (eds) Proceedings of the First International Conference on Planktonic Microfossils, Geneva, 1967. E J Brill, Leiden 380-381. gs

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Boersma, A., Premoli Silva, I. & Shackleton, N. J. (1987). Atlantic Eocene planktonic foraminiferal paleohydrographic indicators and stable isotope paleoceanography. Paleoceanography. 2: 287-331. gs

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Leckie, R. M., Farnham, C. & Schmidt, M. G. (1993). Oligocene planktonic foraminifer biostratigraphy of Hole 803D (Ontong Java Plateau) and Hole 628A (Little Bahama Bank), and comparison with the southern high latitudes. Proceedings of the Ocean Drilling Program, Scientific Results. 130: 113-136. gs

Nishi, H. & Chaproniere, G. C. H. (1994). Eocene-Oligocene subtropical planktonic foraminifers at Site 841,. Proceedings of the Ocean Drilling Program, Scientific Results. 135: 245-266. gs

Pearson, P. N. & Chaisson, W. P. (1997). Late Paleocene to middle Miocene planktonic foraminifer biostratigraphy, Ceara Rise. Proceedings of the Ocean Drilling Program, Scientific Results. 154: 33-68. 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 O

Pearson, P. N., Olsson, R. K., Spezzaferri, S. & Leckie, R. M. (2018a). Taxonomy, biostratigraphy, and phylogeny of Oligocene Globanomalinidae (Turborotalia and Pseudohastigerina). In, Wade, B. S., Olsson, R. K., Pearson, P. N., Huber, B. T. & Berggren, W. A. (eds) Atlas of Oligocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication . 46(Chap 14): 403-414. gs

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Postuma, J. A. (1971). Manual of planktonic foraminifera. Elsevier for Shell Group, The Hague. 1-406. 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. (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


Turborotalia increbescens compiled by the pforams@mikrotax project team viewed: 11-12-2023

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