- species arranged by first occurrence (time control age-window is: 0-800Ma)
Oligocene/Late Eocene species
Chiloguembelina adriatica Like C. cubensis but test outline more rapidly flaring, greater apical angle of about 55-60°, a more rapid increase in chamber size and generally a shorter and wider test.
Chiloguembelina cubensis Like C. ototara but with fine costae parallel to the long axis of the test.
Chiloguembelina ototara Test short to somewhat elongate, moderately to rapidly expanding, subtriangular, periphery rounded rather than compressed; usually 11-12, up to 15 chambers; sutures depressed, perpendicular to slightly oblique to growth axis; Aperture moderately narrow to broad symmetrical arch centered or slightly off-center, bordered on one side by a narrow lip.
Early Eocene species
Chiloguembelina parallela Test short and thick, tapering rapidly toward its base. Aperture centrally located, symmetrical, high and narrow.
Chiloguembelina trinitatensis Test biserial with chambers that increase uniformly in breadth and height. Aperture symmetrically centered, low-arched with a narrow, equidimensional lip.
Chiloguembelina wilcoxensis Test large, with broadly rounded periphery, rapid chamber size increase in the initial portion of the test. Aperture symmetrically centered, low-arched to semicircular with an equidimensional lip.
Chiloguembelina crinita Test biserial throughout; aperture is marked by a narrow lip, infolded on one side, and expanded into a distinct apertural flange on the opposite side. Later chambers are subglobular. The sutures distinct and depressed. Test microperforate and last chambers finely hispid.
Paleocene species
Chiloguembelina subtriangularis Test small, biserial with subangular periphery, subtriangular in side view. Chambers, slightly inflated,broadening though ontogeny, successive chambers slightly overlapping the previous one. Sutures nearly straight, at low angle with the growth axis. Aperture low, asymmetric arch with lip that narrows toward the center of the chamber.
Chiloguembelina midwayensis Test small, compressed, and rapidly tapering. Early chambers subspherical, later chambers are broadercross the coiling axis and overlap the immediately preceding chambers, can extend almost across test. Aperture of each chamber exhibits only one distinct lateral flange
Chiloguembelina morsei The test biserial throughout. Sutures are distinct and depressed, initially sub-horizontal, oblique between later chambers. Successive chambers overlap, particularly in late ontogeny. Initial chambers sub-spherical, later chambers broader Wall surface with numerous small pustules, especially on early chambers. Aperture with a single distinct lateral flange.
Chiloguembelina sp. Specimens which cannot be assigned to established species
Taxonomy
Citation: Chiloguembelina Loeblich&Tappan, 1956taxonomic rank: GenusType species: Guembelinamidwayensis Cushman, 1940Taxonomic discussion: The microperforate surface texture, apertural asymmetry, and twisted coiling axis are the primary features that unite Chiloguembelina species with woodringinids and other Paleocene descendants of Guembelitriacretacea. The biserial first whorl of Chiloguembelina species distinguishes them from Woodringina species. Beckmann (1957) proposed that Guembelinatrinitatensis Cushman and Renz and Guembelinawilcoxensis Cushman and Ponton descended from Chiloguembelinacrinita (Glaessner). On this basis, Beckmann (1957) assigned trinitatensis and wilcoxensis to the genus Chiloguembelina. [Olsson et al. 1999]
Distinguishing features: Parent taxon (Chiloguembelinidae): Small biserial test, often with a slightly twisted coiling axis. Intercameral sutures distinct, depressed, and often somewhat oblique. Aperture arched, rimmed by narrow lip, and generally infolded on one side of ultimate chamber. This taxon: Test subtriangular in outline, biserial throughout or rarely with multiserial final chambers; aperture a simple arched opening at base of the final chamber, with a narrow rim on one margin and a broad collar or flange directed toward one of the flat sides of the test, lacking an infolded margin or internal plate. Rarely with multiple apertures.
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
Morphology: Test subtriangular in outline, biserial throughout or rarely with multiserial final chambers, initial chambers sometimes slightly twisting; chambers slightly to moderately inflated, increasing slowly to moderately in size; aperture a simple arched opening at base of the final chamber, symmetrically or asymmetrically centered on chamber face, with an inturned, narrow bordering rim on one margin and a broad collar or flange that is directed toward one of the flat sides of the test, lacking an infolded margin or internal plate. Multiple apertures rarely occur on specimens assigned to this genus. [Eocene Atlas] Wall type: Bilamellar, generally microperforate, though low latitude forms may have larger pores; wall texture smooth, finely to moderately pustulose, or finely striate; [Eocene Atlas]
Biogeography and Palaeobiology
Similar speciesDiffers from Heterohelix Ehrenberg (1843) and Laeviheterohelix Nederbragt (1991) by the presence of an asymmetric infolding of the apertural collar; differs from Streptochilus Bronnimann and Resig (1971) by having a narrower and more equal thickness of the apertural collar, lacking an internal plate connecting successive foramina of all chambers, and by having a surface texture that is pustulose or striate rather than smooth to granular. Pore mounds are not present on any species of Chiloguembelina. [Eocene Atlas] Phylogenetic relationsDescended from Woodringina by loss of the initial triserial coiling (Olsson and others, 1999). [Eocene Atlas]
Most likely ancestor:Woodringina - at confidence level 4 (out of 5). Data source: Olsson et al, 1999 f6.
Biostratigraphic distribution
Geological Range: Notes: Lower Danian through middle Oligocene (Zones P -O4). [Eocene Atlas] Last occurrence (top): at top of O5 zone (100% up, 26.9Ma, in Chattian stage). Data source: Total of ranges of the species in this database First occurrence (base): within Pa zone (65.72-66.00Ma, base in Danian stage). Data source: Total of ranges 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: Olsson et al. 1999 - Atlas of Paleocene Planktonic Foraminifera, p. 89
References:
Beckmann, J. P. (1957). Chiloguembelina Loeblich and Tappan and related foraminifera from the Lower Tertiay of Trinidad, B.W.I. In, Loeblich, A. R. , Jr., Tappan, H., Beckmann, J. P., Bolli, H. M., Montanaro Gallitelli & E. Troelsen, J. C. (eds) Studies in Foraminifera. U.S. National Museum Bulletin . 215: 83-95. gs
Brönnimann, P. & Resig, J. (1971). A Neogene globigerinacean biochronologic time-scale of the southwestern Pacific. Initial Reports of the Deep Sea Drilling Project. 7(2): 1235-1469. gsO
Cushman, J. A. (1940). Midway foraminifera from Alabama. Contributions from the Cushman Laboratory for Foraminiferal Research. 16(3): 51-73. gs
Ehrenberg, C. G. (1843b). Verbreitung und Einfluss des mikroscopischen Lebens in Süd- und Nord Amerika. Bericht uber die zu Bekanntmachung geeigneten Verhandlungen der Koniglichen Preussische Akademie der Wissenschaften zu Berlin. 1841: 291-446. 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
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. gsO
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
Nederbragt, A. J. (1991). Late Cretaceous biostratigraphy and development of Heterohelicidae (planktic foraminifera). Micropaleontology. 37: 329-372. 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
Smart, C. W. & Thomas, E. (2007). Emendation of the genus Streptochilus Brönnimann and Resig 1971 (Foraminifera) and new species from the lower Miocene of the Atlantic and Indian Oceans. Micropaleontology. 53(1-2): 73-103, 103 figures, 113 lates, 101 table. gs
Chiloguembelina compiled by the pforams@mikrotax project teamviewed: 11-10-2024
