Daughter taxa (time control age-window is: 0-800Ma)
Cassigerinella chipolensis Like C. eocaenica but test broader and more globular with a planispirally or pseudoplanispirally enrolled coiling mode rather than biserially enrolled.
Cassigerinella eocaenica Test small, flattened, petaloid in outline. Chambers in an enrolled-biserial arrangement with successive chambers facing one another; axis of enrollment fairly constant through ontogeny; chambers compressed, sometimes reniform. Aperture interiomarginal, asymmetrical, highly arched to virguline in shape, with an irregular lip.
Cassigerinella sp. Specimens which cannot be assigned to established species
Riveroinella Bermudez and Seiglie [according to Saito and Biscaye 1977; Kennett & Srinivasan 1983]
Taxonomic discussion: The confused state of the taxonomy of species referred to Cassigerinella was thoroughly discussed by Li (1986). According to Pokorny (1955), the type species, C. boudecensis ( =chipolensis), is characterized by having an initial planispiral stage and presence of a continuously extended toothplate structure. However, Li (1986) demonstrated that the initial chambers of C. boudecensis Pokorny and Cassigerinellachipolensis (Cushman and Ponton) are biserially arranged on a rotating coiling plane, and that species included in the genus possess a variably developed apertural rim or flange rather than a true toothplate. Li’s (1986) dissections of C. boudecensis and C. chipolensis reveal that their wall microstructure is composed of monolamellar, randomly arranged microgranules that may be optically radial. The wall surface texture of Cassigerinella may be smooth and/or with scattered perforation cones. Evidence that Cassigerinella lived a planktonic mode of life is partly based on morphological features, such as its inflated test with globular chambers and presence of pore mounds, a feature not found in benthic species. Of the species included in this genus, only C. chipolensis has a distribution that is typical of planktonic species, as it is widespread and it is abundant in deep sea sediments. Boersma and Shackleton (1978) confirmed a near surface habitat for this species based on their oxygen and carbon isotope analyses. SEM observation of the holotype of Cassigerinellawinniana (Pl. 16.4, Figs. 13-15) reveals the presence of pustules concentrated only in the umbilicus, which is a common feature in benthic foraminifera but not characteristic of planktonic foraminifera. Dissection of specimens assigned to winniana reveals a blocky wall microstructure that is characteristic of rotaliid benthic foraminifera (Pl. 16.4, Fig. 17). For these reasons, and because of its restriction to nearshore paleoenvironments, winniana is now considered a benthic taxon and is assigned to the genus Cassidulina. [Huber et al. 2006]
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
Emended description: Morphology: “Test small, nearly planispiral or irregularly coiled in the first few chambers, becoming low trochospiral in adult; always biserial-enrolled with the chambers alternating in arrangement in the coiling plane (as in Cassidulina); chambers 6-8 per whorl, relatively compressed and compactly together in early ontogeny but usually becoming strongly inflated, ovate to semiglobular in last whorl; aperture interiomarginally alternating, asymmetrical, highly arched to virguline in shape, without toothplate structure, but often with apertural rims or laterally asymmetrical flanges more- or-less developed.” (Li, 1986, p. 60-61). [Huber et al. 2006] Wall type: wall calcareous, optically radial but granular in structure, sparsely pierced by small perforations; pores simple or surrounded by protruding rim-like pore-cones; [Huber et al. 2006] Size:
Biogeography and Palaeobiology
Phylogenetic relations: Because of the absence of a true umbilicus and an assumed planktonic mode of life, Blow (1979) suggested Cassigerinella should be placed in the Heterohelicidae. This proposal was later adopted by Kennett and Srinivasan (1983). Li (1986) included the Cassigerinellidae in the Heterohelicaceae based on the presence of the biserial enrolled test, microperforate wall microstructure, occasional presence of perforation cones, and high apertures with asymmetrical flanges. We follow Li’s (1986) classification rather than that of Loeblich & Tappan (1988), who placed the Cassigerinellidae along with normal perforate genera within the Hantkeninaceae. [Huber et al. 2006]
The first species of the genus, Cassigerinella eoceanica, is thought most likely to have evolved from a benthic foraminifer, possibly a Cassidulina species. [see C. eocaenica]
Most likely ancestor:Benthic foraminifera - at confidence level 2 (out of 5). Data source: .
Biostratigraphic distribution
Geological Range: Notes: Middle Eocene-middle Miocene (Zones E13-M13a). [Huber et al. 2006] 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): in lower part of Bartonian Stage (35% up, 40Ma, in Bartonian stage). Data source: Total of range of species in this database
Plot of occurrence data:
Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested
Primary source for this page: Huber et al. 2006 - Eocene Atlas, chap. 16, p. 484
References:
Blow, W. H. (1979). The Cainozoic Globigerinida: A study of the morphology, taxonomy, evolutionary relationships and stratigraphical distribution of some Globigerinida (mainly Globigerinacea). E. J. Brill, Leiden. 2: 1-1413. gs
Boersma, A. & Shackleton, N. J. (1978). Oxygen and carbon isotope record through the Oligocene, Site 366 (equatorial Atlantic). Initial Reports of the Deep Sea Drilling Project. 41: 957-962. gs
Cushman, J. A. & Ponton, G. M. (1932a). An Eocene foraminiferal fauna of Wilcox age from Alabama. Contributions from the Cushman Laboratory for Foraminiferal Research. 8(3): 51-72. gsVO
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. gsVO
Kennett, J. P. & Srinivasan, M. S. (1983). Neogene Planktonic Foraminifera. Hutchinson Ross Publishing Co., Stroudsburg, Pennsylvania. 1-265. gs
Li, Q. & Radford, S. S. (1991). Evolution and biogeography of Paleogene microperforate planktonic foraminifera. Palaeogeography Palaeoclimatology Palaeoecology. 83: 87-115. gs
Li, Q. (1986). Ultrastructure, morphology, affinities and reclassification of Cassigerinella Pokorny (Foraminiferida: Globigerinina):. Journal of Micropalaeontology. 5: 49-64. gs
Loeblich, A. R. & Tappan, H. (1988). Foraminiferal Genera and Their Classification (Volume I-II). Van Nostrand Reinhold Co., New York. 1-1059. gs
Pokorný, V. (1955). Cassigerinella boudecensis n. gen., n. sp. (Foraminifera, Protozoa) z Oligocénu ždánického flyše. Vestnik Ustredniho Ustavu Geologickeho. 30: 136-140. gs
Saito, T. & Biscaye, P. E. (1977). Emendation of Riveroinella martinezpicoi Bermúdez and Seiglie, 1967, and synonymy of Riveroinella with Cassigerinella Pokorný, 1955. Micropaleontology. 23: 319-329. gs
Cassigerinella compiled by the pforams@mikrotax project teamviewed: 8-8-2022
