Trilobatus subsacculifer


Classification: pf_cenozoic -> Globigerinidae -> Trilobatus -> Trilobatus subsacculifer
Sister taxa: T. sacculifer, T. quadrilobatus, T. immaturus, T. trilobus ⟩⟨ T. bisphericus, T. sicanus ⟩⟨ T. altospiralis, T. praeimmaturus, T. primordius, T. subsacculifer, T. sp.

Taxonomy

Citation: Trilobatus subsacculifer (Cita, Premoli Silva, and Rossi, 1965)
Rank: species
Basionym: Globigerinoides sacculifera subsacculifera Cita, Premoli Silva and Rossi, 1965
Synonyms:
Taxonomic discussion:

Cita and others (1965) suggest that T. subsacculifer evolved into T. sacculifer in the middle Miocene, acquiring specialized characters such as the well-developed sac-like last chamber. However, additional material is needed to prove this phylogenetic relationship. [Spezzaferri et al. 2018]

Catalog entries: Globigerinoides sacculifera subsacculifera

Type images:

Distinguishing features: Like T. sacculifer but last chamber only weakly sac-like chamber; test generally smaller; tande primary aperture is a lower and smaller

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


Wall type: Normal perforate, spinose, sacculifer-type wall.

Morphology: Low trochospiral, consisting of 3 whorls, subtriangular to triangular and lobate in outline, 4 subspherical to reniform chambers in the last whorl, increasing slowly in size. The last chamber is slightly sac-like and may be smaller than the previous ones. Sutures are depressed, slightly curved on the spiral side and straight on the umbilical side. Umbilicus narrow and slightly depressed. Primary aperture a low umbilical arch, sometimes bordered by a thin rim. One to two supplementary small low arched apertures are present along the sutures. [Spezzaferri et al. 2018]

Size: Maximum diameter of holotype 0.25 mm. [Spezzaferri et al. 2018]

Character matrix

test outline:Lobatechamber arrangement:Trochospiraledge view:Equally biconvexaperture:Umbilical
sp chamber shape:Globularcoiling axis:Low-moderateperiphery:N/Aaperture border:Thin lip
umb chbr shape:Globularumbilicus:Wideperiph margin shape:Broadly roundedaccessory apertures:Sutural
spiral sutures:Moderately depressedumb depth:Deepwall texture:Cancellateshell porosity:Macroperforate: >2.5µm
umbilical or test sutures:Strongly depressedfinal-whorl chambers:4.0-4.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: This species is most abundant at middle and low latitudes (Spezzaferri, 1994). [Spezzaferri et al. 2018]

Isotope paleobiology: A well constrained stable isotope paleobiology is presently not available. However, the few data reported in Bicchi and others (2003) suggest that it was a mixed-layer dweller. [Spezzaferri et al. 2018]

Phylogenetic relations: Trilobatus subsacculifer evolved from T. trilobus just above the Subzone M1a/M1b boundary. [Spezzaferri et al. 2018]

Most likely ancestor: Trilobatus trilobus - at confidence level 3 (out of 5). Data source: .
Likely descendants: Trilobatus sacculifer;

Biostratigraphic distribution

Geological Range:
Notes: Trilobatus subsacculifer ranges from just above the Miocene Subzone M1a/M1b boundary (Spezzaferri, 1994) to the Tortonian, upper Miocene Zone M13 (Cita and others, 1965). Additional and comparative material is needed to prove its presence in sediments younger than Zone M13. [Spezzaferri et al. 2018]
Last occurrence (top): within M13 zone (6.14-9.83Ma, top in Messinian stage). Data source: Spezzaferri et al. 2018
First occurrence (base): within M1b subzone (21.12-22.44Ma, base in Aquitanian stage). Data source: Spezzaferri et al. 2018

Plot of occurrence data:

Primary source for this page: Spezzaferri et al. 2018 - Olig Atlas chap.9 p.298

References:

Bicchi, E., Ferrero, E. & Gonera, M. (2003). Palaeoclimatic interpretation based on Middle Miocene planktonic foraminifera: the Silesia Basin (Paratethys) and Monferrato (Tethys) records. Palaeogeography Palaeoclimatology Palaeoecology. 196: 265-303. gs

Bizon, G. & Bizon, J. -J. (1972). Atlas des Pricipaux Foraminiferes Planctoniques du Bassin Mediterraneen Oligocene a Quaternaire. Technip, France. -. gs

Brady, H. B. (1877). Supplementary note on the foraminifera of the Chalk (?) of the New Britain group. Geological Magazine. 4(12): 534-536. gs

Cita, M. B., Premoli Silva, I. & Rossi, R. C. (1965). Foraminiferi planctonici del Tortoniano- tipo. Rivista Italiana di Paleontologia e Stratigrafia. 71: 271-308. gs V O

Spezzaferri, S. (1994). Planktonic foraminiferal biostratigraphy and taxonomy of the Oligocene and lower Miocene in the oceanic record. An overview. Palaeontographia Italica. 81: 1-187. gs

Spezzaferri, S., Olsson, R. K. & Hemleben, C. (2018c). Taxonomy, biostratigraphy, and phylogeny of Oligocene to Lower Miocene Globigerinoides and Trilobatus. 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 9): 269-306. gs V O


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Trilobatus subsacculifer compiled by the pforams@mikrotax project team viewed: 17-1-2021

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Short stable page link: http://mikrotax.org/pforams/index.php?id=104369 Go to Archive.is to create a permanent copy of this page - citation notes



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