According to Pearson and Wade (2015), taci is morphologically and evolutionarily intermediate between D. galavisi and D. tapuriensis. [Wade et al. 2018]
Catalog entries: Dentoglobigerina taci
Type images:Distinguishing features: 3½ globular chambers in final whorl.
Umbilicus open, square; with thin lip.
Wall type: Cancellate and probably spinose in life. [Wade et al. 2018]
Morphology: “Test large, globular, approximately 12-13 chambers arranged in a moderate trochospiral, outline oval and slightly lobate, chambers globular and radially compressed; in spiral view 3½ appressed and embracing chambers in final whorl, increasing moderately to rapidly in size, sutures slightly curved, depressed; in umbilical view 3½ globular and appressed chambers, increasing moderately rapidly in size, sutures depressed, straight or slightly curved, umbilicus moderately wide, rectangular, and deep; aperture umbilical, centrally placed usually with a lip of constant thickness; in edge view chambers globular in shape, embracing, the final chamber tending to lean slightly over the umbilicus. May be dextral or sinistral, with a slight bias in favor of sinistral coiling.” (Pearson and Wade, 2015:18.) [Wade et al. 2018]
Size: Maximum diameter of holotype 0.39 mm. [Wade et al. 2018]
Character matrix
test outline: | Lobate | chamber arrangement: | Trochospiral | edge view: | Concavo-convex | aperture: | Umbilical |
sp chamber shape: | Globular | coiling axis: | Moderate | periphery: | N/A | aperture border: | Thin lip |
umb chbr shape: | Globular | umbilicus: | Wide | 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: | Strongly depressed | final-whorl chambers: | 3.5-3.5 | N.B. These characters are used for advanced search. N/A - not applicable |
Geographic distribution: Low latitudes, currently confirmed only from the Indian Ocean (Tanzania), Gulf of Mexico (US Gulf Coast) and equatorial Pacific Ocean (IODP Site U1334). [Wade et al. 2018]
Isotope paleobiology: Multispecies stable isotope data indicate negative δ18O values in comparison to the rest of the assemblage, suggesting calcification in the mixed-layer (Moore and others, 2014, recorded as Dentoglobigerina sp. 1). [Wade et al. 2018]
Phylogenetic relations: Evolved from D. galavisi in the upper Eocene (Pearson and Wade, 2015) and is ancestral to D. tapuriensis. [Wade et al. 2018]
Most likely ancestor: Dentoglobigerina galavisi - at confidence level 4 (out of 5). Data source: Pearson & Wade 2015, p19.
Likely descendants: Dentoglobigerina prasaepis;
Geological Range:
Notes: Uppermost Eocene to lower Oligocene. The highest occurrence has yet to be determined. [Wade et al. 2018]
Last occurrence (top): within O1 zone (32.10-33.90Ma, top in Rupelian stage). Data source: Wade et al. 2018 f11.1
First occurrence (base): within E16 zone (33.90-34.68Ma, base in Priabonian stage). Data source: Wade et al. 2018 f11.1
Plot of occurrence data:
Primary source for this page: Wade et al. 2018 - Olig Atlas chap.11 p.365;
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 Moore, T. C. et al. (2014). Equatorial Pacific Productivity Changes near the Eocene-Oligocene Boundary. Paleoceanography. 29: 825-844. 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 OReferences:
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Dentoglobigerina taci compiled by the pforams@mikrotax project team viewed: 18-1-2021
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