Morozovella gracilis


Classification: pf_cenozoic -> muricate non-spinose -> Truncorotaloididae -> Morozovella -> Morozovella gracilis
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 gracilis (Bolli 1957)
Rank: Species
Basionym: Globorotalia formosa gracilis
Synonyms:
Taxonomic discussion: Morozovella gracilis occupies a morphologic/phylogenetic position intermediate between M. subbotinae and M .formosa(see also Pearson,1993).It differs from the former in the increased number of chambers (5-6) in the final whorl, which is associated with a looser (more evolute) coiling mode, and in the elevated spiral intercameral sutures. Morozovella formosa is characterized by a further increase in size and number of chambers (6-8) in the last whorl and concomitant increase in the width of the umbilicus. Like most other morozovellids, particularly those morphotypes closely associated with the aequa -subbotinae -gracilis -marginodentata -formosa plexus, it has a complicated taxonomic history, which is discussed in Berggren (1977) and Blow (1979). Globorotalia bolli El-Naggar (1966), it appears, includes morphotypes of this plexas. We regard his pl. 22: fig. 6a-d as a morphotype of M. gracilis, in contrast to the holotype (pl. 22: fig. 5a-d), which is a morphotype of M. subbotinae. [Olsson et al. 1999]

Catalog entries: Globorotalia bollii;
Globorotalia formosa gracilis;

Type images:

Distinguishing features: Planoconvex to moderately biconvex test, with lobulate peripheral margin ornamented with a well developed muricocarina; 5-6 essentially equidimensional chambers in last whorl; umbilical intercameral sutures radial, straight, depressed; on spiral side strongly curved, distinctly muricate except for penultimate/ultimate chamber suture which is straight giving cuneiform shape to final chamber (not unlike the shape in Acarinina triplex); umbilical surface covered with muricae, spiral side weakly muricate except for concentration of muricae along intercameral sutures and peripheral margin of ultimate whorl; small sutural openings along margin/junction of ultimate/penultimate whorl resulting from chamber addition along topographically separated/elevated muricate edges; umbilicus narrow, deep; aperture a low interiomarginal, umbilical-extraumbilical arch extending towards, but not to, the peripheral margin.

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: Planoconvex to moderately biconvex test, with lobulate peripheral margin ornamented with a well developed muricocarina; 5-6 essentially equidimensional chambers in last whorl; umbilical intercameral sutures radial, straight, depressed; on spiral side strongly curved, distinctly muricate except for penultimate/ultimate chamber suture which is straight giving cuneiform shape to final chamber (not unlike the shape in Acarinina triplex); umbilical surface covered with muricae, spiral side weakly muricate except for concentration of muricae along intercameral sutures and peripheral margin of ultimate whorl; small sutural openings along margin/junction of ultimate/penultimate whorl resulting from chamber addition along topographically separated/elevated muricate edges; umbilicus narrow, deep; aperture a low interiomarginal, umbilical-extraumbilical arch extending towards, but not to, the peripheral margin. [Olsson et al. 1999]

Character matrix

test outline:Lobatechamber arrangement:Trochospiraledge view:Planoconvexaperture:-
umb chamber shape:Subtriangularcoiling axis:Very lowperiphery:Single keelaperture border:N/A
sp chbr shape:Petaloidumbilicus:Narrowperiph margin shape:Subangularaccessory apertures:None
umbilical or test sutures:Strongly depressedumb depth:Deepwall texture:Spinoseshell porosity:Finely Perforate: 1-2.5µm
spiral sutures:Weakly depresseddiameter mm:width mm:-breadth mm:0.5
final-whorl chambers:5.0-6.0

Biogeography and Palaeobiology


Geographic distribution: This is a geographically widespread morphospecies recorded from (predominantly) (sub)tropical biogeographies. It occurs as far south as nearly 60° at ODP Sites 738 (Huber, 1991b) and 747 (Berggren, 1992) on the Kerguelen Plateau, southern Indian Ocean, as part of the earliest Eocene extra-tropical excursion of morozovellids. [Olsson et al. 1999]
Aze et al. 2011 summary: Cosmopolitan; based on Olsson et al. (1999)

Isotope paleobiology: No data available. [Olsson et al. 1999]
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 species evolved from M. subbotinae through a reduction in spire height and an increase in the number of chambers. [Olsson et al. 1999]

Most likely ancestor: Morozovella subbotinae - at confidence level 4 (out of 5). Data source: Berggren & Pearson (2006) f11.1; Olsson et al. 1999.

Biostratigraphic distribution

Geological Range:
Notes: Zone P5 to Zone P6b. [Olsson et al. 1999]
Last occurrence (top): at top of E5 zone (100% up, 50.7Ma, in Ypresian stage). Data source: Olsson et al. (1999) f5a
First occurrence (base): in upper part of E2 zone (60% up, 55.4Ma, in Ypresian stage). Data source: Olsson et al. (1999) f5a

Plot of occurrence data:

Primary source for this page: Olsson et al. 1999 - Atlas of Paleocene Planktonic Foraminifera, p. 61

References:

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.

Berggren, W.A., (1977). Atlas of Palaeogene Planktonic Foraminifera: some Species of the Genera Subbotina, Planorotalites, Morozovella, Acarinina and Truncorotaloides. In: Ramsay, A.T.S. (Editor), Oceanic Micropaleontology. Academic Press, London, pp. 205-300.

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.

Bolli, H.M., (1957). Planktonic foraminifera from the Eocene Navet and San Fernando formations 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. 155-172.

Huber, B.T., (1991). Paleogene and Early Neogene Planktonic Foraminifer Biostratigraphy of Sites 738 and 744, Kerguelen Plateau (Southern Indian Ocean). Proceedings of the Ocean Drilling Program, Scientific Results, 119: 427-449.

Jenkins, D.G., (1971). New Zealand Cenozoic Planktonic Foraminifera. New Zealand Geological Survey, Paleontological Bulletin, 42: 1-278.

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). Paleocene and Early Eocene planktonic foraminifera Leg 32, Deep Sea Drilling Project. Initial Reports of the Deep Sea Drilling Project, 32: 725-728.

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

Pearson, P.N., (1993). A lineage phylogeny for the Paleogene planktonic foraminifera. Micropaleontology, 39: 193-232.

Shutskaya, E.K., (1970). Stratigrafiya, foraminifery i paleogeografiya nizhnego paleogena Kryma, predkavkaz'ya i zapadnoi chadsti srednei azii [Stratigraphy, Foraminifera and Paleogeography of the Lower Paleogene in the Crimea, Precaucasus and the Western Part of Central Asia]. Trudy, Vsesoyuznyi Nauchno-lssledovadetel 'skii Geologorazvedochnyi Neftyanoi Institut (VNIGNI), 70: 256 pages.

Snyder, S.W. & Waters, V.J., (1985). Cenozoic planktonic foraminiferal biostratigraphy of the Goban Spur Region, Deep Sea Drilling Project Leg 80. Initial Reports of the Deep Sea Drilling Project, 80: 439-472.

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


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

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