Catalog - Dentoglobigerina eotripartita

CATALOG OF ORIGINAL DESCRIPTIONS: Dentoglobigerina eotripartita Pearson, Wade & Olsson, in Wade et al.  2018

This page provides data from the catalog of type descriptions. The catalog is sorted alphabetically. Use the current identification link to go back to the main database.


Higher levels: pf_cat -> D -> Dentoglobigerina -> Dentoglobigerina eotripartita
Other pages this level: D. eotripartita, D. juxtabinaiensis, D. taci

Dentoglobigerina eotripartita

Citation: Dentoglobigerina eotripartita Pearson, Wade & Olsson, in Wade et al.  2018
Rank: Species
Type specimens: Holotype (NHMUK PM PF 71285) and paratypes (NHMUK PM PF 71286 to 71288)
Type sample (& lithostrat): Tanzania Drilling Project Site 12, in the Kilwa Group of Tanzania
Type age (chronostrat): upper Eocene Zone E15/E16 (Zone E16 equivalent)
Type locality: Tanzania
Type repository: London; NHM

Current identification/main database link: Dentoglobigerina eotripartita Pearson, Wade, and Olsson, in Wade et al. 2018


Original Description

Type of wall: Normal perforate, cancellate, pustulose, probably spinose in life.

Test morphology: Test, compact, globular, chambers arranged in a tight, low trochospiral, subcircular to subquadrate in equatorial outline, moderately lobate; in spiral view 3-3½ ovoid compressed chambers in ultimate whorl, increasing rapidly in size, sutures straight or slightly curved, depressed; in umbilical view 3 ovoid chambers in ultimate whorl, increasing rapidly in size, sutures straight and incised, umbilicus moderate in size, aperture centered deep in the umbilicus, bordered by a thin, irregular, subtriangular-shaped lip or tooth which tends to point down the opposing suture; in edge view test oval in outline, chambers ovoid in shape, ultimate chamber projects above and bends over the umbilicus.


Size:
Maximum diameter of holotype 0.42 mm, minimum diameter 0.34 mm, thickness 0.41 mm.

Etymology:
Eo = dawn; tripartita = in three parts, the name of Koch’s taxon with which this species has previously been confused; eotripartita = the ‘tripartita’ typical of the Eocene.

Extra details from original publication

DISTINGUISHING FEATURES. Dentoglobigerina eotripartita is distinguished from D. galavisi by its more compact morphology with 3 tightly coiled, more rapidly increasing chamber size in the final whorl and by possessing a more overarching and compressed final chamber. This species differs from D. tripartita by its smaller size, and less spherical, less compressed/reniform overall morphology, and from D. pseudovenezuelana by more tightly coiled chambers and tooth pointing down the opposing suture.

DISCUSSION. This species was initially identified in the Atlas of Eocene Planktonic Foraminifera (2006) as D. tripartita (Koch). At that time, an SEM of the tripartita holotype was unavailable and identification relied on a drawing of the holotype by Blow and Banner (1962), which was interpreted as a slightly deformed specimen, so we followed the well defined concept of this species set out by Blow (1969, 1979). The new holotype SEM of tripartita (Koch) (Pl. 11.14, Figs. 1-3) clearly shows, however, the large, robust, subspherical, test of this species, which is typical of the Oligocene, but is different from the specimens illustrated by Blow, and from D. cf. tripartita (Pearson and Wade, 2015). Dentoglobigerina eotripartita n. sp. is thus described to represent this smaller more compact morphotype typical of the Eocene, which was probably ancestral to the more robust tripartita sensu stricto.

PHYLOGENETIC RELATIONSHIPS. Dentoglobigerina eotripartita n. sp. descended from D. galavisi in the middle Eocene (Olsson and others, 2006) and probably gave rise to D. tripartita in the lower Oligocene (Pearson and Wade, 2015).

STRATIGRAPHIC RANGE. The first appearance is in upper Eocene Zone E14 according to Olsson and others (2006) although the oldest figured specimen is from Zone E15 (Olsson and others, 2006, pl. 13.3, fig. 4). This form probably developed gradually into D. tripartita by becoming larger and more spherical. All of our illustrated specimens are from the upper Eocene, but the eotripartita like morphology persists in the record until at least the upper Oligocene Zone O7 (see the dissections of Blow, 1969, pl. 29, figs. 3 and 5, and the discussion under tripartita). Our youngest confirmed occurrence is from Zone O1.

GEOGRAPHIC DISTRIBUTION. Global at low to mid-latitudes.

STABLE ISOTOPE PALEOBIOLOGY. Stable isotope data indicate a thermocline habitat, becoming deeper with increasing test size (Wade and Pearson, 2008, recorded as D. tripartita; see also Pearson and Wade, 2015).


Editors' Notes
This species was informally described by Pearson & Wade (2015) as Dentoglobigerina cf. tripartita and then formally described in Wade et al. 2018 as D. eotripartita. The same images were used in both papers but the versions in Pearson & Wade (2015) were reproduced at higher resolution and so are used here. [editor's comment - JRY 2018]

References:

Blow, W. H. & Banner, F. T. (1962). The mid-Tertiary (Upper Eocene to Aquitanian) Globigerinaceae. In, Eames, F. E., Banner, F. T., Blow, W. H. & Clarke, W. J. (eds) Fundamentals of mid-Tertiary Stratigraphical Correlation. Cambridge University Press, Cambridge 61-151. gs

Blow, W. H. (1979). The Cainozoic Globigerinida: A study of the morphology, taxonomy, evolutionary relationships and stratigraphical distribution of some Globigerinida (mainly Globigerinacea). E. J. Brill, Leiden. 2: 1-1413. gs

Olsson, R. K., Hemleben, C. & Pearson, P. N. (2006b). Taxonomy, biostratigraphy, and phylogeny of Eocene Dentoglobigerina. 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 13): 401-412. gs V O

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 V O

Wade, B. S., Pearson, P. N., Olsson, R. K., Fraass, A. J., Leckie, R. M. & Hemleben, C. (2018c). Taxonomy, biostratigraphy, and phylogeny of Oligocene and Lower Miocene Dentoglobigerina and Globoquadrina. 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 11): 331-384. gs V O


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Dentoglobigerina eotripartita compiled by the pforams@mikrotax project team viewed: 4-7-2022

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