pforams@mikrotax - Globorotalia crassaformis

Citation: Globorotalia crassaformis (Galloway & Wissler, 1927)

Basionym: Globigerina crassaformis

Synonyms:

Globorotalia (Truncorotalia) crassaformis (Galloway & Wissler, 1927) - e.g. Kennett & Srinivasan 1983
Globorotalia crotonensis Conato & Follador 1967 [according to Brummer & Kucera 2022]
Globorotalia crassacrotonensis Conato & Follador 1967 [according to Brummer & Kucera 2022]

Variants:

Globorotalia (Turborotalia) oceanica Cushman & Bermudez, 1949 = Globorotalia crassaformis subsp. oceanica Cushman & Bermudez, 1949 [according to Kennett & Srinivasan 1983, Brummer & Kucera 2022]. This form is similar to G. crassaformis but has greater chamber rounding, it occurs throughout the range of G. crassaformis but in the modern ocean it is not recognised as a discrete species (Brummer & Kucera 2014, 2022).

NB Globorotalia crassaformis ronda Blow, 1969 and Globorotalia crassaformis viola Blow 1969, and Globorotalia crassaformis hessi Bolli and Premoli Silva, 1973 have also been considered as variants but were separated as distinct species by Aze et al. (2011).
Lam & Leckie (2020) stated that "we do not recognize the different subspecies of Globorotalia crassaformis (e.g., G. viola, G. ronda, G. oceanica). Determining if these subspecies are actually valid are outside the scope of this study, so we refrain from completely synonymizing them with G. crassaformis. Instead, we apply a wide range of intra-species variability to the G. crassaformis species."

Taxonomic discussion: Globorotalia crassaformis oceanica Cushman and Bermudez, 1949 is considered a synonym by Kennett & Srinivasan 1983 (folowing Cifelli & Glacon 1979) - but Aze et al. (2011) regard it as a discrete species.

Distinguishing features:
Parent taxon (truncatulinoides lineage): G. crasula - crassaformis - tosaensis - truncatulinoides lineage, predominantly conicotruncate
This taxon: No keel & flat spiral side

Description

Test low trochospiral, spiral side almost flat, umbilical side strongly convex, equatorial periphery slightly lobulate, subquadrate; axial periphery planoconvex, sub-acute to subrounded; chambers compressed, 4 in the final whorl, increasing rapidly in size; sutures on spiral side curved, depressed; on umbilical side almost radial, depressed; surface finely perforate, pustulate on umbilical as well as spiral side; umbilicus narrow, deep; aperture interiomarginal, extraumbilical-umbilical, a low-arched slit bordered by a lip. [Kennett & Srinivasan 1983]

Biogeography and Palaeobiology

Warm subtropical to temperate. [Kennett & Srinivasan 1983] Low to middle latitudes [Aze et al. 2011, based on Kennett & Srinivasan (1983)]. An important element of sub-thermocline faunas in tropical to temperate regions [Brummer & Kucera 2022]Map of distribution from ForCenS database

Aze et al. 2011 ecogroup 4 - Open ocean sub-thermocline. Based on very light δ¹³C and very heavy δ¹⁸O. Sources cited by Aze et al. 2011 (appendix S3): Stewart (2003).

Gr. (T) crassaformis shows a wide range of variation in size, from rounded to keeled periphery, thin-walled to thick-walled test, and the degree of compactness. Different subspecific nomenclature such as oceanica Cushman and Bermudez, 1949; ronda Blow, 1969; viola Blow, 1969, and hessi Bolli and Premoli Silva, 1973, have been proposed to reflect these variations. All of these forms are characterized by four chambers in the final whorl and quadrate arrangement of quasi-scituline shaped chambers (Cifelli and Glacon, 1979), suggesting close phyletic relationships between them.
Gr. (T) crassaformis may have evolved from Gr. (T) crassula and is the ancestor of Gr. (T) tosaensis Takayanagi and Saito. [Kennett & Srinivasan 1983]

Most likely ancestor: Globorotalia crassula - at confidence level 2 (out of 5). Data source: Kennet & Srinivasan (1983). NB Stewart (2003 fig. 6.10) & Aze et al. (2011, appendix 5) derive G. crassaformis from G. cibaoensis, however this appears to be in large part due to their adopting an incorrect age for the base of G. crassaformis, hence we revert here to the interpretation of Kennett & Srinivasan (1983) .
Likely descendants: Globorotalia crassaconica; Globorotalia ronda; Globorotalia viola; plot with descendants

Biostratigraphic distribution

Geological Range:
Last occurrence (top): Extant. Data source: present in the plankton (SCOR WG138)
First occurrence (base): near base of PL2 zone (12% up, 4.3Ma, in Zanclean stage). Data source: Wade et al. (2011), additional event; position within zone determined by linear interpolation from data in table 1 of Wade et al. (2011).

References:

Aze, T. et al. (2011). A phylogeny of Cenozoic macroperforate planktonic foraminifera from fossil data. Biological Reviews. 86: 900-927. gs

Blow, W. H. (1969). Late middle Eocene to Recent planktonic foraminiferal biostratigraphy. In, Bronnimann, P. & Renz, H. H. (eds) Proceedings of the First International Conference on Planktonic Microfossils, Geneva, 1967. E J Brill, Leiden 380-381. gs

Bolli, H. M. & Premoli Silva, I. (1973). Oligocene to Recent planktonic foraminifera and stratigraphy of the Leg 15 sites in the Caribbean Sea. Initial Reports of the Deep Sea Drilling Project. 15: 475-497. gs

Brummer, G. J. A. & Kucera, M. (2014). SCOR/ICBP 138 taxonomy and key to species of modern planktonic foraminfera v2.1. In, Chart distributed at TMS FNG meeting Texel, The Netherlands, June 2014. 1-. gs

Brummer, G-J. A. & Kucera, M. (2022). Taxonomic review of living planktonic foraminifera. Journal of Micropalaeontology. 41: 29-74. gs

Cifelli, R. & Glacon, G. (1979). New Late Miocene and Pliocene occurrences of Globorotalia species from the North Atlantic; and a paleogeographic review. Journal of Foraminiferal Research. 9(3): 210-227. gs

Conato, V. & Follador, U. (1967). Globorotalia crotonensis e Globorotalia crassacrotonensis nuove species del Pliocene Italiano. Bollettino della Societa Geologica Italiana. 84: 555-563. gs

Crundwell, M. P. (2018). Globoconella pseudospinosa, n. sp.: A new Early Pliocene planktonic foraminifera from the Southwest Pacific. Journal of Foraminiferal Research. 48(4): 288-300. gs

Cushman, J. A. & Bermudez, P. J. (1949). Some Cuban species of Globorotalia. Contributions from the Cushman Laboratory for Foraminiferal Research. 25: 26-45. gs O

Galloway, J. J. & Wissler, S. G. (1927). Pleistocene foraminifera from the Lomita Quarry, Palos Verdes Hills, California. Journal of Paleontology. 1(1): 35-87. gs

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

Lam, A. & Leckie, R. M. (2020a). Late Neogene and Quaternary diversity and taxonomy of subtropical to temperate planktic foraminifera across the Kuroshio Current Extension, northwest Pacific Ocean. Micropaleontology. 66(3): 177-268. gs

Loeblich, A. & Tappan, H. (1994). Foraminifera of the Sahul shelf and Timor Sea. Cushman Foundation for Foraminiferal Research, Special Publication. 31: 1-661. gs O

Norris, R. D. (1998). Planktonic foraminifer biostratigraphy: Eastern Equatorial Atlantic. Proceedings of the Ocean Drilling Program, Scientific Results. 159: 445-479. gs O

Postuma, J. A. (1971). Manual of planktonic foraminifera. Elsevier for Shell Group, The Hague. 1-406. 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

Stewart, D. R. M. I. (2003). Evolution of Neogene globorotaliid foraminifera and Miocene climate change. PhD thesis, Bristol University. 1-269. gs O

test outline:	Subquadrate	chamber arrangement:	Trochospiral	edge view:	Planoconvex	aperture:	Umbilical-extraumbilical
sp chamber shape:	Subrectangular	coiling axis:	Low	periphery:	N/A	aperture border:	Thin lip
umb chbr shape:	Subtriangular	umbilicus:	Narrow	periph margin shape:	Subangular	accessory apertures:	None
spiral sutures:	Flush	umb depth:	Shallow	wall texture:	Smooth	shell porosity:	Macroperforate: >2.5µm
umbilical or test sutures:	Weakly depressed	final-whorl chambers:	4-4	N.B. These characters are used for advanced search. N/A - not applicable

Globorotalia crassaformis

Taxonomy

Description

Biogeography and Palaeobiology

Biostratigraphic distribution

References:

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