Taxonomic discussion: This species was decribed in Globigerionoides but has been placed in Globoturborotalita in most modern analyses, based on the inference that it most likely evolved from Globoturborotalita rubescens (e.g. Kennett & Srinivasan 1983; Aze et al. 2011, Schiebel & Hemleben 2017). However, Morard et al. (2019) used molecular genetics and ontogenetic reconstructions to show that the species nested inside the clade of extant Globigerinoides species and that it was closely related to G. elongatus and G. conglobatus. Based on this they reccomended transfering it back into Globigerinoides.
Distinguishing features: Parent taxon (Globigerinoides): Supplementary apertures, with ruber/sacculifer-type spinose wall texture This taxon: Like G. rubescens but with a small, supplementary aperture.
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
Morphology: Test small, low trochospire , chambers spherical, four in the final whorl, rapidly increasing in size as added; sutures curved and depressed; surface distinctly cancellate with pores set in polygonal pore pits; primary aperture umbilical large, almost circular in outline, with a distinct rim; single small, supplementary aperture on spiral side at intersection of spiral and intercameral sutures. [Kennett & Srinivasan 1983] Wall type: Spinose; Cancellate [Aze 2011] Size: >250µm
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:
Sutural
spiral sutures:
Weakly depressed
umb depth:
Deep
wall texture:
Cancellate
shell porosity:
Macroperforate: >2.5µm
umbilical or test sutures:
Moderately depressed
final-whorl chambers:
4-4
N.B. These characters are used for advanced search. N/A - not applicable
Biogeography and Palaeobiology
Geographic distributionTropical to temperate. [Kennett & Srinivasan 1983] Low latitudes [Aze et al. 2011, based on Kennett & Srinivasan (1983)]
In modern oceans a common, warm water, species [SCOR WG138]
Isotope paleobiologyAze et al. 2011 ecogroup 2 - Open ocean mixed-layer tropical/subtropical, without symbionts; based on comparison with other species of the genus. Phylogenetic relationsGs. tenellus is similar to Globigerina (Zeaglobigerina) rubescens in all respects except for the development of a small, supplementary aperture. This species evolved from Gg. (Zg.) rubescens in the Late Pliocene. [Kennett & Srinivasan 1983]
Most likely ancestor:Globigerinoides elongatus - at confidence level 5 (out of 5). Data source: Morard et al. (2019) - based on mol gen data. NB Kennett & Srinivasan 1983 had suggested origin from G. rubescens.
Biostratigraphic distribution
Geological Range: Last occurrence (top): Extant. Data source: present in the plankton (SCOR WG138) First occurrence (base): within N21 zone (1.93-3.10Ma, base in Piacenzian stage). Data source: Chaisson & Pearson (1997)
Plot of occurrence data:
Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested
Histogram - Neptune occurrence data from DSDP and ODP proceedings. Pale shading <50 samples in time bin. Interpret with caution & read these notes
Primary source for this page: Kennett & Srinivasan 1983, p.80 (as Globigerinoides tenellus)
References:
Aze, T. et al. (2011). A phylogeny of Cenozoic macroperforate planktonic foraminifera from fossil data. Biological Reviews. 86: 900-927. gs
Kennett, J. P. & Srinivasan, M. S. (1983). Neogene Planktonic Foraminifera. Hutchinson Ross Publishing Co., Stroudsburg, Pennsylvania. 1-265. gs
Loeblich, A. & Tappan, H. (1994). Foraminifera of the Sahul shelf and Timor Sea. Cushman Foundation for Foraminiferal Research, Special Publication. 31: 1-661. gsO
Morard, R. et al. (2019a). Genetic and morphological divergence in the warm-water planktonic foraminifera genus Globigerinoides. PLoS One. 14(12): 1-30. gs
Parker, F. L. (1958). Eastern Mediterranean foraminifera. Reports of the Swedish Deep-Sea Expedition, 1947-1948. 8(4): 217-283. gs
Schiebel, R. & Hemleben, C. (2017). Planktic Foraminifers in the Modern Ocean. Springer-Verlag, Heidelberg. 1-358. gs
Siccha, M. & Kucera, M. (2017). ForCenS, a curated database of planktonic foraminifera census counts in marine surface sediment samples. Scientific Data. 4(1): 1-12. gs
Globigerinoides tenellus compiled by the pforams@mikrotax project teamviewed: 11-9-2024