pforams@mikrotax - Guembelitria

Citation: Guembelitria Cushman, 1933

Type species: Guembelitria cretacea Cushman, 1933.

Synonyms: Chiloguembelitria Hofker, 1978:60.

Taxonomic discussion: Confusion remains over the taxonomic status of Chiloguembelitria, which Loeblich and Tappan (1988) retained as a valid genus and Kroon and Nederbragt (1990) suggested is a junior synonym of Guembelitria. This confusion is exacerbated by the absence of a designated holotype for Chiloguembelitria or its type species, Chiloguembelitria danica Hofker, 1978. Nonetheless, it appears that no morphological characters consistently distinguish Chiloguembelitria spp. from Guembelitria spp. The original description and illustration of C. danica Hofker, 1978, resembles Guembelitria cretacea Cushman, 1933, in its apertural characteristics and its consistent triseriality (Plate 63). The absence of distinct chiloguembelitriid characters indicates that, as suggested by Kroon and Nederbragt (1990), Chiloguembelitria danica Hofker, 1978, is a junior synonym of Guembelitria cretacea Cushman, 1933. [Olsson et al. 1999]

Distinguishing features:
Parent taxon (Guembelitriidae): Tests triserial, trochospiral, or nearly triserial in initial whorl becoming biserial. Chambers usually globular or subglobular, increasing gradually in size. Aperture usually a loop-shaped arch, often slightly infolded on one side, marked by a fine lip.
This taxon: Test small and triserial. Aperture bordered by a distinct lip and often slightly asymmetric. Wall structure microperforate; surface texture of well-preserved specimens characterized by presence of pore-mounds.

Description

Biogeography and Palaeobiology

Biostratigraphic distribution

Geological Range:
Last occurrence (top): at top of P1b subzone (100% up, 63.9Ma, in Danian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within G. elevata zone (79.33-83.65Ma, base in Campanian stage). Data source: Total of ranges of species in this database

Primary source for this page: Olsson et al. 1999 - Atlas of Paleocene Planktonic Foraminifera, p. 79

References:

Cushman, J. A. (1933c). Some new foraminiferal genera. Contributions from the Cushman Laboratory for Foraminiferal Research. 9(2): 32-38. gs

El-Naggar, Z. R. (1971a). On the classification, evolution and stratigraphical distribution of the Globigerinacea. In, Farinacci, A. (ed.) Proceedings of the Second Planktonic Conference, Roma 1970. Edizioni Tecnoscienza, Rome (1): 421-476. gs

Haynes, J. R. (1981). Foraminifera. John Wiley and Sons, New York. -. gs

Hofker, J. (1978). Analysis of a large succession of samples through the Upper Maastrichtian and Lower Tertiary of Drill Hole 47.2, Shatsky Rise, Pacific, Deep Sea Drilling Project. Journal of Foraminiferal Research. 8(1): 46-75. gs

Huber, B. T., Olsson, R. K. & Pearson, P. N. (2006). Taxonomy, biostratigraphy, and phylogeny of Eocene microperforate planktonic foraminifera (Jenkinsina, Cassigerinelloita, Chiloguembelina, Streptochilus, Zeauvigerina, Tenuitella, and Cassigerinella) and Problematica (Dipsidripella). In, Pearson, P. N., Olsson, R. K., Hemleben, C., Huber, B. T. & Berggren, W. A. (eds) Atlas of Eocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication . 41(Chap 16): 461-508. gs O

Jenkins, D. G., Whittaker, J. E. & Curry, D. (1998). Palaeogene triserial planktonic foraminifera. Journal of Micropalaeontology. 17: 61-70. gs

Kroon, D. & Nederbragt, A. J. (1990). Ecology and paleoecology of triserial planktic foraminifera. Marine Micropaleontology. 16: 25-38. gs

Loeblich, A. R. & Tappan, H. (1956). Chiloguembelina, a new Tertiary genus of the Heterohelicidae (Foraminifera). Journal of the Washington Academy of Sciences. 46: 340-. gs

Loeblich, A. R. & Tappan, H. (1988). Foraminiferal Genera and Their Classification (Volume I-II). Van Nostrand Reinhold Co., New York. 1-1059. gs

Olsson, R. K., Hemleben, C., Berggren, W. A. & Huber, B. T. (1999). Atlas of Paleocene Planktonic Foraminifera. Smithsonian Institution Press, Washington, DC. (85): 1-252. gs

Ujiie, Y., Kimoto, K. & Pawlowski, J. (2008). Molecular evidence for an independent origin of modern triserial planktonic foraminifera from benthic ancestors. Marine Micropaleontology. 69: 334-340. gs

Guembelitria

Taxonomy

Description

Biogeography and Palaeobiology

Biostratigraphic distribution

References:

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Comments

Daughter taxa (time control age-window is: 0-800Ma)
			Guembelitria cretacea Test small, triserial; chambers globular with strongly depressed sutures; aperture with a distinct lip and often slightly asymmetric.
			Guembelitria sp. Specimens which cannot be assigned to established species