Pearsonites


Classification: pf_cenozoic -> Truncorotaloididae -> Pearsonites
Sister taxa: Alicantina, Acarinina, Praemurica, Igorina, Pearsonites, Planorotalites, Astrorotalia, Morozovella, Morozovelloides,
Daughter taxa: (blue => in age window 0-800Ma)
Pearsonites sensu Soldan et al. 2014
Like I. broedermanni but with more plano-convex test; more chambers (8-9) in final whorl; wider and deeper umbilicus; and tendency towards an intraumbilically restricted aperture.
Biconvex to planoconvex test with 6-7 chambers in fine whorl. Like I. lodoensis but with less lobulate periphery and flatter spiral side.
Test small, lobulate, equally biconvex, densely muricate; narrow umbilicu; essentially straight radial sutures on the umbilical side.

Taxonomy

Citation: Pearsonites Soldan, Petrizzo & Premoli Silva 2014
Rank: Genus
Type species: Globorotalia (Truncorotalia) broedermanni Cushman & Bermudez, 1949
Taxonomic discussion: The species icluded here in Pearsonites were inlcuded in Igorina by Olsson et al. (2006). However, Soldan et al. (2011, 2014) argued that the genus was polyphytletic with the broedermanni group of species having evolved indepedantly from Acarinina.

Catalog entries: Pearsonites

Distinguishing features: small Morozovellids with biconvex–planoconvex tests with an overall rounded periphery

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


Diagnostic characters:

 


Wall type: Nonspinose with thin muricae.

Test morphology: Test low trochospiral, weakly biconvex to planoconvex, with 6–10 chambers in the last whorl. Spiral side with subglobular to subquadrate chambers that increase very gradually in size; sutures slightly depressed to flush and slightly recurved to oblique. Umbilical side with triangular chambers; sutures nearly straight, depressed. Umbilicus generally widely bordered by coalescing circumumbilical muricae. Aperture a low arch extending toward the peripheral margin that is subrounded to subangular. [Soldan et al. 2014]

Biogeography and Palaeobiology

Most likely ancestor: Acarinina - at confidence level 4 (out of 5). Data source: Soldan et al 2011, Soldan et al 2014 (fig. 2).

Biostratigraphic distribution

Geological Range:
Last occurrence (top): in upper part of Lutetian Stage (69% up, 43.2Ma, in Lutetian stage). Data source: Total of range of species in this database
First occurrence (base): in upper part of Thanetian Stage (76% up, 56.7Ma, in Thanetian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

Soldan, D. M., Petrizzo, M. R., Silva, I. P. & Cau, A. (2011). Phylogenetic relationships and evolutionary history of the Paleogene genus through parsimony analysis. Journal of Foraminiferal Research. 41: 260-284. gs

Soldan, D. M., Petrizzo, M. R. & Silva, I. P. (2014). Pearsonites, a new Paleogene planktonic foraminiferal genus for the broedermanni lineage. Journal of Foraminiferal Research. 44: 17-27. gs


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Pearsonites compiled by the pforams@mikrotax project team viewed: 19-10-2019

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Short stable page link: http://mikrotax.org/pforams/index.php?id=104398 Go to Archive.is to create a permanent copy of this page - citation notes



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