pforams@mikrotax - Morozovella edgari pforams@mikrotax - Morozovella edgari

Morozovella edgari

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


Citation: Morozovella edgari (Premoli Silva & Bolli 1973)
taxonomic rank: Species
Basionym: Globorotalia edgari
Taxonomic discussion: This minute morozovellid (test diameter ranges from 0.2-0.25 mm) is associated with, and ranges beyond, terminal members of the Morozovella velascoensis group. Kelly and others (2001, p. 507) have suggested that edgari descended from velascoensis by a process called “terminal progenesis” in which the diminutive descendant (edgari) with an adult morphology resembles the juvenile stages of the ancestral form velascoensis.
Morozovella finchi Blow is placed in the synonomy of this taxon. It shares most morphologic features in common with edgari except that the holotype is somewhat larger (0.32 mm) in diameter. It was described from Zone P5 (of Blow, 1979) and said to range to Zone P7 (=E4 of this paper), a range comparable to that ascribed to edgari here. Blow (1979, p. 999-1000) was of the opinion that finchi descended from “Acarininatrichotrocha and even included a paratype from the Hornerstown Formation (Zone P4) of New Jersey (erroneously ascribed to Zone P5) in his new taxon finchi, but our examination of this form at the USNM suggests that this specimen is not ascribable to finchi ( =edgari). [Berggren & Pearson 2006]

Catalog entries: Globorotalia edgari, Globorotalia (Morozovella) finchi

Type images:

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

This taxon: Like M. velascoensis but smaller and with weaker muricocarina. Very similar to juveniles of M. velascoensis and may have evolved from it by paedomorphosis.

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.


Low to moderately conical trochospiral; weakly lobulate peripheral outline, 5-6 gradually enlarging , cuneiform-shaped chambers in last whorl, intercameral sutures on umbilical side radial, straight and weakly incised; chambers trapezoidal in shape, separated by distinctly curved sutures which are flush with the test; early part/chambers of the test raised (i.e., the test exhibits an unequal biconvexity); umbilicus narrow, deep; distinct muricocarina extends to final chamber; aperture a low umbilical-extraumbilical arch extending nearly to the periphery; surface distinctly muricate with concentration of pustules decreasing towards terminal chambers. [Berggren & Pearson 2006]

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

Dimensions of holotype: maximum diameter: 0.21 mm. [Berggren & Pearson 2006]

Character matrix
test outline:Lobatechamber arrangement:Trochospiraledge view:Inequally biconvexaperture:Umbilical-extraumbilical
sp chamber shape:Crescenticcoiling axis:Lowperiphery:Muricocarinateaperture border:N/A
umb chbr shape:Subtriangularumbilicus:Narrowperiph margin shape:Subangularaccessory apertures:None
spiral sutures:Flushumb depth:Deepwall texture:Moderately muricateshell porosity:Finely Perforate: 1-2.5µm
umbilical or test sutures:Weakly depressedfinal-whorl chambers:5-6 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology

Geographic distribution

Probably widely distributed in (sub)tropical regions (Caribbean, Atlantic Ocean and Pacific Ocean) but records are sparse owing to this taxon having been overlooked heretofore. We have found this form relatively commonly distributed in lower Eocene strata (Esna Shales) of Egypt. [Berggren & Pearson 2006]
Aze et al. 2011 summary: Low latitudes; based on Berggren & Pearson (2006)

Isotope paleobiology
Shallow-intermediate depth-habitat (Kelly and others, 2001). [Berggren & Pearson 2006]
Aze et al. 2011 ecogroup 1 - Open ocean mixed-layer tropical/subtropical, with symbionts. Based on very heavy _13C and relatively light _18O. Sources cited by Aze et al. 2011 (appendix S3): Kelly et al. (2001)

Phylogenetic relations
This taxon evolved from Morozovella velascoensis (by means of a gradual decrease in test size and truncation of the ancestral ontogenetic sequence; Kelly and others, 2001) but does not appear to have left any descendants. [Berggren & Pearson 2006]

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

Biostratigraphic distribution

Geological Range:
Notes: Zone E2 (uppermost part) to Zone E3. [Berggren & Pearson 2006]
Last occurrence (top): at top of E3 zone (100% up, 54.6Ma, in Ypresian stage). Data source: Berggren & Pearson (2006) f11.1
First occurrence (base): in mid part of E2 zone (50% up, 55.5Ma, in Ypresian stage). Data source: Berggren & Pearson (2006) f11.1

Plot of occurrence data:

Primary source for this page: Berggren & Pearson 2006 - Eocene Atlas, chap. 11, p. 362


Berggren, W. A. & Pearson, P. N. (2006a). Taxonomy, biostratigraphy, and phylogeny of Eocene Morozovella. 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 11): 343-376. gs O

Blow, W. H. (1979). The Cainozoic Globigerinida: A study of the morphology, taxonomy, evolutionary relationships and stratigraphical distribution of some Globigerinida (mainly Globigerinacea). E. J. Brill, Leiden. 2: 1-1413. gs

Kelly, D. C., Bralower, T. J. & Zachos, J. C. (2001). On the demise of the Early Paleogene Morozovella velascoensis lineage: Terminal progenesis in the planktonic foraminifera. Palaios. 16: 507-523, 511 figures, 502 tables, 501 aendix. gs

Premoli Silva, I. & Bolli, H. M. (1973). Late Cretaceous to Eocene planktonic foraminifera & stratigraphy of Leg 15 Sites in the Caribbean Sea. Initial Reports of the Deep Sea Drilling Project. 15: 449-547. gs

Toumarkine, M. & Luterbacher, H. (1985). Paleocene and Eocene planktic foraminifera. In, Bolli, H. M., Saunders, J. B. & Perch-Neilsen, K. (eds) Plankton Stratigraphy. Cambridge Univ. Press, Cambridge 87-154. gs


Morozovella edgari compiled by the pforams@mikrotax project team viewed: 21-6-2024

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