Fohsella


Classification: pf_cenozoic -> Globorotaliidae -> Fohsella
Sister taxa: Berggrenia, Dentigloborotalia, Fohsella, Globoconella, Globorotalia, Neogloboquadrina, Pulleniatina,
Daughter taxa: Species in lineage order, oldest at base (blue => in age window 0-800Ma)
Late Miocene species
Like G. lenguaensis but less circular and test less tightly coiled
Small with circular equatorial profile, and smooth, densely perforate, test
main lineage
Like G. lobata but nearly circular outline and more convex umbilical side.
Like G. fohsi but larger and with characteristic cockscomb-shaped peripheral margin
Like G. praefohsi, but with a distinct keel throughout the entire final whorl.
Like G. peripheroacuta but with a keel (imperforate carina) on the final 1 or 2 chambers
Like G. peripheroronda but acutely compressed periphery in the later chambers of the final whorl.
Umbilico-convex, very low trochospiral, equatorial periphery slightly lobulate

Taxonomy

Citation: FohsellaBandy 1972
Rank: Genus
Basionym: Globorotalia (Fohsella) Bandy 1972
Type species: Globorotalia (Globorotalia) praefohsi Blow and Banner, 1966
Synonyms:
Taxonomic discussion: The subgenus Fohsella was proposed by Bandy (1972) for the well-known G. peripheroronda to Gr. fohsi robusta bioseries. In his diagnosis, Bandy (1972) restricted the name Fohsella for sharp- to keel-edged members only. We agree with Fleisher (1974) in considering this definition to be too restrictive and that forms should also be included with a rounded periphery such as Gr. peripheroronda, Gr. birnageae, and Gr. kugleri because they represent early members of the Fohsella lineage (Text Fig. 12).
The subgenus Fohsella is an important lineage in the tropics and forms the basis for the early Middle Miocene planktonic foraminiferal zonation (Bolli, 1957a, Blow, 1969). The evolutionary development of this bioseries has been well documented by a number of authors (Bolli, 1957a, 1967; Blow and Banner, 1966; Olsson, 1971, 1972; Srinivasan and Kennett, 1981a).
Important changes within the Fohsella lineage are a size increase of specimens and the development of a nonkeeled to a keeled periphery. A sudden and rapid increase in average test size in later members of the Fohsella lineage was interpreted by Olsson (1972) to be in response to the climax of global climatic warming during the Middle Miocene. All of the species included in the subgenus Fohsella are marked by a smooth, secondary calcite crust, which covers and sometimes obscures the pores in the early chambers (PI.21,Figs.1,2).The early members of this lineage- Gr. (F.) kugleri, Gr. (F.) peripheroronda, and Gr. (F.) birnageae-morphologically resemble forms included in the new subgenus Jenkinsella [=Paragloborotalia] but are phylogenetically unrelated. The ancestry of the subgenus Fohsella is uncertain. [Kennett & Srinivasan 1983].

Following discussion among members of the Neogene planktonic formainiferal working group we are now using the name Fohsella on mikrotax. This reflects the observations that (1) The genus was validly propsed by Bandy (1972); (2) The genus has a separate evolutionary origin, within Paragloborotalia, from the main Globorotalia lineage; (3) This usage has been followed by many workers. [editor's comment - JRY, May 2019].


Catalog entries: Globorotalia (Fohsella)

Distinguishing features: G. peripheroronda - lenguaensis - fohsi - robusta lineage

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

Biogeography and Palaeobiology


Phylogenetic relations: Both Aze et al. (2011) and Leckie et al. (2018) record the fohsi lineage as originating from Paragloborotalia. Since it is imterpreted as having a separate origin from the other Globorotalia lineages the name Fohsella should be used. [editor's comment - JRY 2018]

Within the main fohsi lineage there is a shift from random coiling to predominantly sinistral coiling within zone N12 (=M9) this was outlined by Bolli & Saunders (1985) and documented in more detail by Winter & Pearson (2001).

Most likely ancestor: Paragloborotalia - at confidence level 3 (out of 5). Data source: Leckie et al. (2018).

Biostratigraphic distribution

Geological Range:
Last occurrence (top): in upper part of Messinian Stage (58% up, 6.1Ma, in Messinian stage). Data source: Total of range of species in this database
First occurrence (base): near top of Chattian Stage (91% up, 23.5Ma, in Chattian stage). Data source: Total of range of species in this database

Plot of occurrence data:

Primary source for this page: Kennett & Srinivasan 1983 p.91

References:

Bandy, O. L. (1972). Origin and development of Globorotalia (Turborotalia) pachyderma (Ehrenberg). Micropaleontology. 18(3): 294-318. gs

Bolli, H. M. & Saunders, J. B. (1985). Oligocene to Holocene low latitude planktic foraminifera. In, Bolli, H. M. , Saunders, J. B. & Perch-Neilsen, K. (eds) Plankton Stratigraphy. Cambridge University Press, Cambridge, UK 155-262. gs

Fleisher, R. L. (1974a). Cenozoic planktonic foraminifera and biostratigraphy, Arabian Sea, Deep Sea Drilling Project, Leg 23A. Initial Reports of the Deep Sea Drilling Project. 23: 1001-1072. gs

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

Winter, C. J. & Pearson, P. N. (2001). Coiling directions in some Miocene planktonic Foraminifera. Journal of Micropalaeontology. 20(1): 29-30. gs


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Fohsella compiled by the pforams@mikrotax project team viewed: 15-12-2019

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Short stable page link: http://mikrotax.org/pforams/index.php?id=104029 Go to Archive.is to create a permanent copy of this page - citation notes



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