Morozovelloides


Classification: pf_cenozoic -> Truncorotaloididae -> Morozovelloides
Sister taxa: Acarinina, Praemurica, Igorina, Planorotalites, Astrorotalia, Morozovella, Morozovelloides,
Daughter taxa: (blue => in age window 0-300Ma)
Test biconvex, very thin; chambers elongate, wedge-shaped; surface smooth except for blade-like to fimbriate peripheral muricocarina. Grades into M. coronatus in the lower part of its range, but has more elongate and more numerous chambers
Like M. crassatus but muricae clustered on the circumumbilical tips of the chambers forming a ‘coronet’ - like ornament; umbilicus open.
Test asymmetrically low-biconvex, sometimes nearly planoconvex; umbilicus closed to narrow
Distinguished from all other species of Morozovelloides by the strongly disjunct long axes of the chambers, as seen in spiral view.
Specimens which cannot be assigned to established species

Taxonomy

Citation: Morozovelloides Pearson and Berggren 2006
Rank: Genus
Type species: Globorotalia lehneri Cushman and Jarvis, 1929
Taxonomic discussion: The new genus accommodates several lower-middle Eocene species that have generally been placed in Morozovella in recent years, but which are believed to have evolved from Acarinina. The concept of Morozovelloides was developed in discussions with R. D. Norris (pers. comm., 2001).
[Pearson & Berggren 2006]

Catalog entries: Morozovelloides;

Type images:

Distinguishing features: Like Morozovella, but derived from Acarinina.

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: Morozovelloides n. gen. is highly convergent in morphology with some true Morozovella. It is considered in this work to be derived from Acarinina.


Wall type: Muricate, with a tendency for concentration of the muricae around the periphery and umbilical region and possessing smooth areas on the spiral side. Test morphology: Low trochospiral, generally lobulate or petaloid in outline, with concentration of bladed muricae around the periphery forming a discontinuous muricocarina. Four to eight chambers in the final whorl; aperture umbilical-extraumbilical or wholly extraumbilical. ETYMOLOGY.— Similar to Morozovella. [Pearson & Berggren 2006]

Test morphology: Planispiral, biumbilicate or showing a subtly raised spiral side and very shallow umbilicus; 4-7 chambers in the final whorl; chambers rounded in the early stages, adult chambers radially elongated, triangular, polygonal or spherical, laterally compressed or highly inflated; some or all of the adult chambers extend into hollow non-porous tubulospines, of variable length, shape and orientation, or, in the case of H. singanoae n. sp., the chambers possess a distinct terminal nub or porous “proto-tubulospine”; peripheral outline (excluding tubulospines) varies from stellate, with deep incisions between chambers, to angular, smooth-continuous or gently lobed; the aperture is a single equatorial arch bordered by a distinctive lip of variable width, symmetrical or slightly asymmetrical.
[Pearson & Berggren 2006]

Biogeography and Palaeobiology

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

Biostratigraphic distribution

Geological Range:
Notes: Restricted to the middle Eocene, Zones E7-E13. [Pearson & Berggren 2006]
Last occurrence (top): near top of Bartonian Stage (93% up, 38Ma, in Bartonian stage). Data source: Total of range of species in this database
First occurrence (base): near top of Ypresian Stage (94% up, 48.3Ma, in Ypresian stage). Data source: Total of range of species in this database

Plot of occurrence data:

Primary source for this page: Pearson & Berggren 2006 - Eocene Atlas, chap. 10, p. 329

References:

Cushman, J.A. & Jarvis, P.W., (1929). New foraminifera from Trinidad. Contributions from the Cushman Laboratory for Foraminiferal Research, 5: 6-17.

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


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Morozovelloides compiled by the pforams@mikrotax project team viewed: 15-12-2018

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