Morozovella formosa


Classification: pf_cenozoic -> muricate non-spinose -> Truncorotaloididae -> Morozovella -> Morozovella formosa
Sister taxa: M. caucasica, M. crater, M. aragonensis, M. lensiformis, M. subbotinae, M. marginodentata, M. formosa, M. gracilis, M. aequa, M. apanthesma, M. angulata, M. praeangulata, M. edgari, M. allisonensis, M. velascoensis, M. acuta, M. occlusa, M. pasionensis, M. acutispira, M. conicotruncata, M. sp.,

Taxonomy

Citation: Morozovella formosa (Bolli 1957)
Rank: Species
Basionym: Globorotalia formosa formosa
Synonyms:
Taxonomic discussion: Blow (1979, p. 1000, 1001) drew attention to the fact that formosa and the crater -caucasica complex, while seemingly morphologically distinct when treated as isolated individuals, in fact require close scrutiny in order to retain the biostratigraphic utility of both. He further pointed out the gross homeomorphy between formosa and some morphotypes of the older velascoensis. Finally he observed that some of the phylogenetically advanced morphotypes of the velascoensis and the lensiformis-crater -caucasica “gens” exhibit features in common with formosa; a sort of “threefold homeomorphy” as he dubbed it. Distinction among the different morphotypes was made on the following basis:
1. formosa is flat to slightly convex in dorsal (spiral) aspect with chambers somewhat longer (anterio-posteriorly) tangentially than broad radially.
2. formosa has dorsal /spiral intercameral sutures nearly radial proximally but recurved (but not sharply retorse) near periphery.
3. velascoensis has chambers in dorsal/spiral aspect nearly equidimensional and spiral intercameral sutures exhibit retorse distal part.
4. In axial-apertural view anguloconical angle in formosa is markedly acute (~ 45o), whereas in velascoensis it is nearly a right-angle (~ 80-85o); the umbilico-peripheral part of chamber is often somewhat concave in the area between the peripheral test
muricocarina and the “horn-like”, adumbilically pointed umbilical shoulders.
5. Whereas the anguloconical angle in the crater -caucasica group is comparable to that in formosa, the earlier chambers have a more rounded appearance in axial/edge view.
6. The umbilicus in formosa is wide and the angle made by the junction of the chamber walls interior and exterior to the umbilicus is on the order of ~ 40-45o; in crater this angle is ~ 60-65o in the case of the earlier chambers and the umbilical shoulders are more gently rounded, only the last 2-3 chambers exhibiting a strongly reflexed angle between interior and exterior chamber walls.
7. The main distinguishing feature separating formosa from the other forms above is the nature of the early vorticiform spiral intercameral sutures together with the acute conical angle and the distinctly flat spiral side. [Berggren & Pearson 2006]

Catalog entries: Globorotalia formosa formosa;

Type images:

Distinguishing features: This taxon is characterized by its relatively large, robust test, 6-7 (rarely 8) chambers and strongly muricate keel. It is distinguished from its antecedent M. gracilis by its larger, more robust test, larger number of chambers in the last whorl and wider umbilicus, and from its partially contemporaneous homeomorph, M. crater, by its more lobulate periphery and larger number of chambers in the final whorl and less ornamented test.

NB The short diagnoses are used in the tables of daughter-taxa to act as quick summaries of the differences between e.g. species of one genus. They have initially been copied from the diagnostic characters/distinguishing features sections of the Eocene and Paleocene Atlases, they will be edited as the site is developed.

Description


Diagnostic characters: This taxon is characterized by its relatively large, robust test, 6-7 (rarely 8) chambers and strongly muricate keel. It is distinguished from its antecedent M. gracilis by its larger, more robust test, larger number of chambers in the last whorl and wider umbilicus, and from its partially contemporaneous homeomorph, M. crater, by its more lobulate periphery and larger number of chambers in the final whorl and less ornamented test. [Berggren & Pearson 2006]

Wall type: Muricate, nonspinose, normal perforate. [Berggren & Pearson 2006]

Test morphology: Test subcircular, moderately lobulate peripheral outline, planoconvex; chambers triangular, inflated and subangular on umbilical side; trapezoidal with curved margins on spiral side; 15-18 chambers arranged in approximately 3 whorls on spiral side and generally 6-6½ chambers (rarely 7-8) in final whorl on umbilical side with muricae scattered on early chambers of last whorl; sutures moderately depressed, weakly curved (early chambers) to straight, radial (later chambers) on last whorl; umbilicus open, moderately wide, deep; primary aperture a low umbilical-extraumbilical arch extending to peripheral margin; gradual increase in chamber size throughout although last 2-3 chambers exhibit varying size; muricate sutures strongly curved, flush with/slightly elevated above test surface; umbilico-convex in edge view; spiral side flat or nearly so; strongly muricate keel. [Berggren & Pearson 2006]

Size: Dimensions of holotype: maximum diameter: 0.65 mm. [Berggren & Pearson 2006]

Character matrix

test outline:Subcircularchamber arrangement:Trochospiraledge view:Umbilico-convexaperture:-
umb chamber shape:Subtriangularcoiling axis:Lowperiphery:Single keelaperture border:N/A
sp chbr shape:Trapezoidalumbilicus:Wideperiph margin shape:Subangularaccessory apertures:None
umbilical or test sutures:Moderately depressedumb depth:Deepwall texture:Moderately muricateshell porosity:Finely Perforate: 1-2.5µm
spiral sutures:-diameter mm:0.65width mm:breadth mm:
final-whorl chambers:6.0-6.5

Biogeography and Palaeobiology


Geographic distribution: Widely distributed in (sub)tropical regions (Caribbean Sea, Atlantic, Pacific, Tethyan, Indian and Austral Oceans). [Berggren & Pearson 2006]
Aze et al. 2011 summary: Low latitudes; based on Berggren & Pearson (2006)

Isotope paleobiology: No data available. [Berggren & Pearson 2006]
Aze et al. 2011 ecogroup 1 - Open ocean mixed-layer tropical/subtropical, with symbionts. Based on very heavy δ13C and relatively light δ18O. Sources cited by Aze et al. 2011 (appendix S3): this study

Phylogenetic relations: This taxon evolved from M. gracilis and does not appear to have left any descendants. [Berggren & Pearson 2006]

Most likely ancestor: Morozovella gracilis - at confidence level 4 (out of 5). Data source: Berggren & Pearson (2006) f11.1.

Biostratigraphic distribution

Geological Range:
Notes: Base of Zone E4 (by definition) to top of Zone E6 (by definition). [Berggren & Pearson 2006]
The FAD of Morozovella formosa marks the base of zone E4 / top of E3 (Wade et al. 2011)
Last occurrence (top): at top of E6 zone (100% up, 50.2Ma, in Ypresian stage). Data source: Berggren & Pearson (2006) f11.1
First occurrence (base): at base of E4 zone (0% up, 54.6Ma, in Ypresian stage). Data source: zonal marker (Wade et al. 2011)

Plot of occurrence data:

Primary source for this page: Berggren & Pearson 2006 - Atlas of Eocene Planktonic Foraminifera, chapter 11, p. 365

References:

Berggren, W.A. & Pearson, P.N., (2006). Taxonomy, biostratigraphy, and phylogeny of Eocene Morozovella. In: Pearson, P.N. et al. (Editors), Atlas of Eocene Planktonic Foraminifera, Cushman Foundation Special Publication 41. Cushman Foundation Special Publication. 41 Allen Press, Lawrence, Kansas, pp. 343-376.

Berggren, W.A., (1971). Paleogene planktonic foraminiferal faunas on Legs I-IV (Atlantic Ocean) JOIDES Deep Sea Drilling Program: a synthesis. In: Farinacci, A. (Editor), Proceedings of the II Planktonic Conference, Roma 1970. Edizioni Tecnoscienza, Rome, pp. 57-77.

Bermudez, P.J., (1961). Contribucion al estudio de las Globigerinidea de la region Caribe-Antillana (Paleoceno-Reciente). Mem. III Congreso Geol. Venez., 3. Editorial Sucre, Caracas, 1119-1393 pp.

Blow, W.H., (1979). The Cainozoic Globigerinida: A study of the morphology, taxonomy, evolutionary relationships and stratigraphical distribution of some Globigerinida (mainly Globigerinacea), 2. E. J. Brill, Leiden, 1413 pp.

Bolli, H.M., (1957). The genera Globigerina and Globorotalia in the Paleocene-Lower Eocene Lizard Springs Formation of Trinidad. In: Loeblich, A.R., Jr. et al. (Editors), Studies in Foraminifera, U.S. National Museum Bulletin 215. U.S. Government Printing Office, Washington, D.C., pp. 61-82.

Cushman, J.A. & Renz, H.H., (1946). The foraminiferal fauna of the Lizard Springs formation of Trinidad, British West Indies. Cushman Laboratory for Foraminiferal Research Special Publication, 18: 1-48.

Cushman, J.A., (1925). Some new foraminifera from the Velasco shale of Mexico. Contributions from the Cushman Laboratory for Foraminiferal Research, 1(6): 18-23.

Luterbacher, H.P., (1964). Studies in some Globorotalia from the Paleocene and Lower Eocene of the Central Apennines. Eclogae Geologicae Helvetiae, 57: 631-730.

Luterbacher, H.P., (1975). Planktonic Foraminifera of the Paleocene and Early Eocene, Possagno Section. Schweizerische Palaontologische Abhandlungen, 97: 57-67.

Stainforth, R.M.; Lamb, J.L.; Luterbacher, H.; Beard, J.H. & Jeffords, R.M., (1975). Cenozoic planktonic foraminiferal zonation and characteristics of index forms. The University of Kansas Paleontological Contributions, 62: 1-425.

Toumarkine, M. & Luterbacher, H., (1985). Paleocene and Eocene planktic foraminifera. Plankton Stratigraphy. Cambridge Univ. Press, Cambridge, 87-154 pp.

Wade, B.S.; Pearson, P.N.; Berggren, W.A. & Pälike, H., (2011). Review and revision of Cenozoic tropical planktonic foraminiferal biostratigraphy and calibration to the geomagnetic polarity and astronomical time scale. Earth-Science Reviews, 104: 111-142.

Warraich, M.Y. & Ogasawara, K., (2001). Tethyan Paleocene-Eocene planktic foraminifera from the Rakhi Nala and Zinda Pir land sections of the Sulaiman Range, Pakistan. Science Reports of the Institute of Geosciences, University of Tsukuba, Section B = Geological Sciences, 22: 1-59.


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Morozovella formosa compiled by the pforams@mikrotax project team viewed: 22-7-2018

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