pforams@mikrotax - Trilobatus pforams@mikrotax - Trilobatus

Trilobatus


Classification: pf_cenozoic -> Globigerinidae -> Trilobatus
Sister taxa: Beella, Globigerina, Globigerinella, Protentella, Quiltyella ⟩⟨ Ciperoella, Globigerinoides, Globigerinoidesella, Globoturborotalita, Orbulina, Praeorbulina, Sphaeroidinella, Sphaeroidinellopsis, Trilobatus, Turborotalita ⟩⟨ Dentoglobigerina, Globoquadrina ⟩⟨ Catapsydrax, Clavatorella, Paragloborotalia, Protentelloides ⟩⟨ Eoglobigerina, Globigerinatheka, Globorotaloides, Guembelitrioides, Orbulinoides, Parasubbotina, Pseudoglobigerinella, Subbotina
Daughter taxa (time control age-window is: 0-800Ma)
sacculifer group (conspecific in modern ocean)
Trilobatus sacculifer
Low trochospiral, chambers spherical except final one which is sac-like on mature specimens
Trilobatus quadrilobatus
3½-4 globular chambers in the last whorl.
Trilobatus immaturus
Like T. trilobus but slightly more lobate and the primary aperture is a low umbilical arch across the antepenultimate chamber.
Trilobatus trilobus
3 globular chambers in the last whorl, slit-like aperture
transitional to Orbulina
Trilobatus bisphericus
Bilobate outline, enveloping last chamber almost completely hides the umbilicus
Trilobatus sicanus
Subspherical to spherical
other species
Trilobatus altospiralis
Like T. primordius but with a high trochospire, up to 4 chambers in the last whorl, and slit-like primary and supplementary apertures.
Trilobatus praeimmaturus
Like T. immaturus and T. trilobus but more subcircular and compact outline; aperture slit-like encompassing the penultimate chamber, and usually 4 chambers in the final whorl.
Trilobatus primordius
Last chamber forms half of the test; low trochospiral, lobulate;  3½ globular, slightly embracing chambers in the last whorl, increasing rapidly in size; sutures depressed; Primary aperture umbilical arch with a thin rim; one small arched supplementary sutural aperture.
Trilobatus subsacculifer
Like T. sacculifer but last chamber only weakly sac-like chamber; test generally smaller; tande primary aperture is a lower and smaller
Trilobatus sp.
Specimens which cannot be assigned to established species

Taxonomy

Citation: Trilobatus Spezzaferri et al. 2015
taxonomic rank: genus
Type species: Trolobatus trilobus
Synonyms:
Taxonomic discussion: The genus Globigerinoides was used by Kennett & Srinivasan (1983) and many other workers for all Neogene  Globigerina-type species with supplementary apertures, but it was long suspected that this was a polyphyletic group. Spezzaferri et al. (2015) conclusively proved this polyphyly using both stratophentic and molecular genetic data and so divided the species into two groups - Trilobatus and Globigerinoides, as used here. They have separate origins and different wall structures. [editor's comment - JRY 2018]

Catalog entries: Trilobatus, Trilobigerina

Distinguishing features:
Parent taxon (Globigerinidae): Wall spinose, usually with 3½-6 globular chambers in final whorl, trochospiral or planispiral
This taxon: Supplementary apertures and cancellate wall.

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:
Low to high trochospiral consisting of 3 whorls. The peripheral margin is rounded, the test outline is compact to lobate, slightly ovate or subtriangular to subrectangular. Chambers can be globular to ovate, symmetrical to enlarged and embracing or irregular and laterally compressed. They are generally 3 to rarely 4 in the last whorl increasing from fast to gradually in size as added. The primary aperture is an umbilical-extraumbilical elongated slit, sometimes moderately high arched and characterizes a generally narrow and concealed umbilical area. Supplementary apertures are present on the spiral side, slit-like or low to high arched, placed at the intersection of the spiral sutures, one per chamber. Thin lips may be present on the primary and supplementary apertures. The last chamber may be sac-like. [Spezzaferri et al. 2018]

Wall type:
Cancellate, honeycomb, sacculifer-type, with spines regularly distributed. Gametogenetic calcification may obscure spines holes.. [Spezzaferri et al. 2018]

Biogeography and Palaeobiology


Geographic distribution


Phylogenetic relations
Trilobatus evolved from Globoturborotalita paracancellata in upper Oligocene Zone O6. [Spezzaferri et al 2018]

Most likely ancestor: Globoturborotalita - at confidence level 3 (out of 5). Data source: Spezzaferri et al 2018.
Likely descendants: Globigerinoidesella; Praeorbulina; plot with descendants

Biostratigraphic distribution

Geological Range:
Last occurrence (top): Extant. Data source: Total of ranges of the species in this database
First occurrence (base): within O6 zone (25.21-26.93Ma, base in Chattian stage). Data source: Total of ranges of species in this database

Plot of occurrence data:

Primary source for this page: Spezzaferri et al. 2015; Spezzaferri et al. 2018

References:

Hemleben, C., Spindler, M. & Anderson, O. (1989). Modern Planktonic Foraminifera. Springer-Verlag, New York. -. gs

Kennett, J. P. & Srinivasan, M. S. (1983). Neogene Planktonic Foraminifera. Hutchinson Ross Publishing Co., Stroudsburg, Pennsylvania. 1-265. gs

Reuss, A. E. (1850). Neue Foraminiferen aus den Schichten des Osterreichischen Tertiarbeckens. Denkschriften der kaiserlichen Akademie der Wissenschaften zu Wien. 1: 365-390. gs O

Spezzaferri, S. et al. (2015). Fossil and genetic evidence for the polyphyletic nature of the planktonic foraminifera "Globigerinoides", and description of the new genus Trilobatus. PLoS One. 1-20. 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


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Trilobatus compiled by the pforams@mikrotax project team viewed: 16-6-2024

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Short stable page link: https://mikrotax.org/pforams/index.php?id=104239 Go to Archive.is to create a permanent copy of this page - citation notes



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Comments (8)

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Paul Pearson(UK)

The Trilobatus / Trilobigerina case is now published and open for comment from the community.

For instructions see https://www.iczn.org/submitting-to-the-bulletin-of-zoological-nomenclature/submitting-to-bzn/case-comments/

This period lasts a minimum of six months before a ruling is made by ICZN. In the interim, prevailing usage (i.e. Trilobatus) should be maintained.

Case 3837 – Trilobatus Spezzaferri, Kucera, Pearson, Wade,

Rappo, Poole, Morard & Stalder, 2015 (Foraminifera,

Globigerinidae): proposed conservation of the genus-group name

by partial suppression of Trilobigerina Popescu, 1987

http://dx.doi.org/10.21805/bzn.v80.a010

Avatar
Paul Pearson

Sorry, for clarification that should be Art 23.9.3 which refers ro Art 82:

"Article 82. Status of case under consideration

82.1. Maintenance of prevailing usage

When a case is under consideration by the Commission, prevailing usage (see Glossary) of names is to be maintained until the ruling of the Commission is published.

82.2. Date when consideration is deemed to begin

A case is deemed to be under consideration by the Commission from the date of publication in the Bulletin of Zoological Nomenclature of the notice of receipt of the case."

The case was originally published in December 2020

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Paul Pearson

(Update as of May 2023)

The Trilobatus / Trilobigerina priority case is still listed online at ICZN as a 'new application'.

https://www.iczn.org/cases/new-applications/case/3837

Apparently there is a substantial backlog dealing with cases.

Article 29.9.3 says "While the case is under consideration use of the junior name is to be maintained" so Trilobatus should be used.

Avatar
Paul Pearson

The case has now been given Case number 3837 by ICZN

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Paul Pearson

Thanks very much for bringing this to out attention Francois! It is a serious issue so today we have submitted a case to the ICZN requesting that it uses its plenary power according to Article 81.2.2 to “partially suppress” Trilobigerina Popescu, 1987 for the purposes of the principle of priority. Note that Article 29.9.3 says "While the case is under consideration use of the junior name is to be maintained" so Trilobatus should be used henceforth unless and until the case is voted down (which we sincerely hope won't happen!) The case will hopefully appear in due course in Bulletin of Zoological Nomenclature and be open to comment. In the meantime if anyone wants more information please contact me.

Please note also that there is a listing on mikrotax under TriGlobigerina (sic). This is just a spelling error so it would be good to delete it

Avatar
Jeremy Young(UK)

Thanks Paul - and the spelling of Trilobigerina has now been corrected.