Morozovella


Classification: pf_cenozoic -> Truncorotaloididae -> Morozovella
Sister taxa: Acarinina, Praemurica, Igorina, Planorotalites, Astrorotalia, Morozovella, Morozovelloides,
Daughter taxa: (blue => in age window 0-300Ma)
caucasica-aragonensis group (Eocene with muricocarina)
Like M. crater but more strongly planoconical test with more chambers (usually 6-8) in the final whorl; umbilicus wider, and  circumumbilical chamber margins strongly ornamented by fused muricae.
It is strongly homeomorphic with M. velascoensis from the late Paleocene-early Eocene (Zone P3b-E2).
Intermediate between M. lensiformis and M. caucasica - 4½ to 5 essentially equidimensional chambers in last whorl, thickened circumumbilical rim of elevated chamber shoulders, strongly limbate sutures on spiral side.
Like M. lensiformis but test planoconvex and with more chambers in final whorl (5-7) and nearly circular; terminal chamber generally smooth.
Test subquadrate, involute, biconvex, with narrow umbilicus; covered by blunt muricae, often obscuring the peripheral muricocarina; 4-4½ chambers in last whorl.
apanthesma-subbotinae group(weak keel)
Morphotype, with pronounced peripheral compression of the chambers on the umbilical side and a thick muricocarina formed form long muricae.
Like M. gracilis but test larger and more robust; more chambers in final whorl (6-7, rarely 8) and wider umbilicus. 
Like M. subbotinae but with lower spire and more chambers (5-6).


Like M. aequa but larger, with sronger muricocarina and more pronounced angulo-conical test; 4-4½ chambers in final whorl.
Like M. apanthesma but with less chambers (usually 4), more involute coiling (and so a more closed umbilicus) and a peripheral muricocarina.
Planoconvex, umbilicoconvex, test with lobulate, weakly muricocarinate periphery; 4-5 chambers in last whorl, inflated to subangular on umbilical side, moderately convex, triangular (lunate) in edge view; intercameral sutures on umbilical side depressed, radially curved and slightly depressed on spiral side; umbilical side distinctly muricate, coarsely perforate on spiral side; umbilicus relatively narrow, deep; aperture an interiomarginal, umbilical-extraumbilical arch with narrow, continuous intraperiumbilical lip.
angluata-velascoensis group (heavy muricate keel)
Like M. velascoensis but smaller and with weaker muricocarina. Very similar to juveniles of M. velascoensis and may have evolved from it by paedomorphosis.
Like M. velascoensis but axially compressed and less ornate; biconvex to mildly planoconvex in edge view; umbilical tips of chambers are relatively rounded and unornamented.
Like M. velascoensis but wth smaller umbilicus, weaker ornament and fewer chambers in final whorl (usually 5).
Like M. acutispira but without raised early part of test.
Like M. pasionensis but with development of a biconvex test; fewer chambers in the final whorl (4-6); and smaller umbilicus. Early part of test raised on spiral side.
Like M. velascoensis but with reduced spire height, a decrease in the ornament around the umbilicus, and an increase in the number of chambers (usually 5-7, up to 10).
Like M. conicotruncata but with coarsely muricate adumbilical ridges and muricocarina; and complete loss of muricae on the chamber surfaces.
Like M. angulata (White) but test more planoconvex; umbilucs more open; and with a low rate of chamber enlargement, and so (5-7) equidimensional chambers in the final whorl.
Like Mpraeangulata but with elaboration of the muricae, development of a peripheral muricocarina, and establishment of anguloconical chambers throughout the last whorl.
Planoconvex, moderately lobulate test with 5-6 tangentially elongate chambers in last last whorl; umbilical sutures straight to weakly curved, incised; spiral intercameral sutures incised, weakly muricate, strongly recurved; peripheral margin strongly muricate but not muricocarinate; umbilicus narrow, deep; aperture an interiomarginal, umbilical-extraumbilical slit (with distinct lip in well preserved specimens).
Specimens which cannot be assigned to established species

Taxonomy

Citation: Morozovella McGowran 1968
Rank: Genus
Type species: Pulvinulina velascoensis Cushman, 1925
Taxonomic discussion: The morozovellids split into two lineages early in their evolution: (1) the M. angulata-M. velascoensis group characterized by the development of muricate adumbilical ridges, a strong muricocarina, and the absence of muricae on parts of the chamber surfaces; and (2) the M. apanthesma-M. subbotinae group whose members are initially unkeeled and entirely covered with fine, thin muricae. [Olsson et al. 1999]

For discusion of correct citation of the name see the taxonomic catalog.

Catalog entries: Morozovella;

Type images:

Distinguishing features: Test typically plano-convex, chambers strongly anguloconical.
Wall strongly pustulose (muricate) on parts of spire and umbilicus. Most species with muricocarina.

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


Diagnostic characters: Strongly anguloconical chambers throughout ontogeny. Surface texture strongly pustulose (muricate) on parts of spire and umbilicus. Most species with muricocarina. [Olsson et al. 1999]

Wall type: Normal perforate (pores cylindrical on at least part of the later chambers); some forms with weakly cancellate early chambers (a feature inherited from their praemuricate ancestry); adult chambers strongly pustulose (muricate) on parts of the spire and umbilicus. [Eocene Atlas]

Test morphology: Test low trochospiral, lobulate outline; strongly anguloconical chambers throughout ontogeny; peripheral margin usually bears distinct muricocarina which passes continuously across at least one intercameral suture (absent or rudimentary in apanthesma); primary aperture interiomarginal, umbilical-extraumbilical; secondary apertures may be present on spiral side but typically lack apertural lips.
[Eocene Atlas]

Biogeography and Palaeobiology


Similar species: Genus distinguished by muricate, anguloconical test and peripheral muricocarina (in nearly all taxa) of variable breadth and strength.
[Eocene Atlas]

Most likely ancestor: Praemurica - at confidence level 0 (out of 5). Data source: Olsson et al. 1999.

Biostratigraphic distribution

Geological Range:
Last occurrence (top): in upper part of Lutetian Stage (69% up, 43.2Ma, in Lutetian stage). Data source: Total of range of species in this database
First occurrence (base): in upper part of Danian Stage (78% up, 62.6Ma, in Danian stage). Data source: Total of range of species in this database

Plot of occurrence data:

Primary source for this page: Olsson et al. 1999 - Atlas of Paleocene Planktonic Foraminifera, p. 54

References:

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.

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.

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.


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Morozovella compiled by the pforams@mikrotax project team viewed: 18-10-2018

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Short stable page link: http://mikrotax.org/pforams/index.php?id=100185Go to Archive.is to create a permanent copy of this page - citation notes



Comments (1)

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François

Hello,

Morozovella was first published as a subgenus of Truncorotaloides. Loeblich and Tappan (1987, p. 478) indicate that the publication of T.(Morozovella) in Luterbacher (1964) is not available because it was published as a synonym of Globorotalia (Opinion of Luterbacher, p. 645)[ICZN art. 11.6]. Therefore T. (Morozovella) was only made available in 1968: McGowran, B. (1968). Reclassification of Early Tertiary Globorotalia. Micropaleontology. 14(2): 179-198.

I hope it helps too,

François

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Jeremy Young (Tonbridge, UK)

Hi Francois

Thank you for that observation. The logic of Loeblich & Tappan seems completely correct to me and I will emend the entries accordingly.

all the best

Jeremy

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