pforams@mikrotax - Cassigerinelloita

Citation: Cassigerinelloita Stolk, 1965, emended Li&Radford, 1992

Type species: Cassigerinelloita amekiensis Stolk, 1965

Taxonomic discussion: Cassigerinelloita was described by Stolk (1965) as belonging to the Cassigerinellidae, despite the fact that the chamber arrangement is not biserial. Loeblich and Tappan (1988) tentatively placed Cassigerinelloita in the Catapsydracidae because of a “microcancellate” wall and presence of bullae. Placement in the Family Guembelitriidae was suggested by Li and Radford (1992) based on the presence of a microperforate, pustulate wall, strongly inflated chambers, and the peculiar triserial coiling mode.
[Huber et al. 2006]

Description

test small (~0.07-0.12 mm), globular, lacking a true umbilicus or distinct periphery; chambers added in a series of triserial, trochospiral coils that are offset following a change or reversal in chamber growth direction that occurs twice to three times during ontogeny; aperture a low, interiomarginal, often indistinct arch, with or without a thin bordering lip, situated on the suture separating the last two chambers and near the early chambers of the outer whorl; occasionally up to three nontriserial chambers formed terminally, each with sutural apertures.
[Huber et al. 2006]

Microperforate and pustulose; [Huber et al. 2006]

Biogeography and Palaeobiology

Li and Radford (1992) suggested that Jenkinsina triseriata is directly ancestral to C. amekiensis based on similarity of wall texture and stratigraphic overlap of the two species.
[Huber et al. 2006]

Most likely ancestor: Jenkinsina - at confidence level 3 (out of 5). Data source: Olsson et al. 1999.

Biostratigraphic distribution

Geological Range:
Notes: Upper lower – lower middle Eocene; lower Zone E7 - upper Zone E9 at low latitudes. First occurs at the base of Zone AE4 at high southern latitudes, which may be slightly earlier than at low latitudes, though the lower range in tropical-subtropical regions is not well documented.
[Huber et al. 2006]
Last occurrence (top): at top of E9 zone (100% up, 43.2Ma, in Lutetian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within E7 zone (45.72-50.20Ma, base in Ypresian stage). Data source: Total of ranges of species in this database

Primary source for this page: Huber et al. 2006 - Eocene Atlas, chap. 16, p. 470

References:

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

Li, Q. & Radford, S. S. (1992). Morphology and affinity of the planktonic foraminifer Cassigerinelloita amekiensis Stolk and reclassification of Cassigerinelloita Stolk. Proceedings of the Ocean Drilling Program, Scientific Results. 120: 595-602. gs

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

Stolk, J. (1965). Contribution à l'étude des corrélations microfaunique do Tertiaire inférieur de la Nigèrie méridionale. Mémoires du Bureau de Recherches Géologiques et Minières. 32: 247-267. gs

Daughter taxa (time control age-window is: 0-800Ma)
			Cassigerinelloita amekiensis Test small, subglobular, with a rotating triserial axis of coiling, indistinguishable umbilicus and often indistinguishable primary aperture.
			Cassigerinelloita sp. Specimens which cannot be assigned to established species