pforams@mikrotax - Morozovella edgari

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.

Eocene_Atlas_pl11-6_fig13-15.jpg
Eocene_Atlas_pl11-6_fig12-16.jpg
Eocene_Atlas_pl11-6_fig8-10.jpg
Eocene_Atlas_pl11-6_fig11.jpg

Taxonomy

Citation: Morozovella edgari (Premoli Silva & Bolli 1973)

taxonomic rank: Species

Basionym: Globorotalia edgari

Synonyms:

Globorotalia edgari Premoli Silva and Bolli 1973:526, pl. 7: figs. 10-12; pl. 8: figs. 1 (holotype)-12 [Globorotalia edgari Zone, DSDP Site152, Nicaragua Rise, Caribbean Sea].
Morozovella edgari (Premoli Silva and Bolli).—Toumarkine and Luterbacher, 1985:114, text-figs. 15.6a (holotype) and 6b, c (paratypes) reillustrated.—Kelly and others, 2001:509, text-fig. 1D-F and text-fig. 3C [lower Eocene, ODP Hole 865B, Allison Guyot, Mid-Pacific Mountains, Pacific Ocean]; text-fig. 2E [Zone P6a, DSDP Site 152, Caribbean Sea].
Globorotalia (Morozovella) finchi Blow, 1979:999, pl. 99: figs. 6-11 (holotype) [Zone P5, DSDP Hole 47.2, Shatsky Rise, Pacific Ocean].

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 “Acarinina” trichotrocha 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:

holotype: G. edgari
paratype: G. edgari
paratype: G. edgari

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.

Description

Morphology:

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]

Size:

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

Character matrix
test outline: Lobate chamber arrangement: Trochospiral edge view: Inequally biconvex aperture: Umbilical-extraumbilical
sp chamber shape: Crescentic coiling axis: Low periphery: Muricocarinate aperture border: N/A
umb chbr shape: Subtriangular umbilicus: Narrow periph margin shape: Subangular accessory apertures: None
spiral sutures: Flush umb depth: Deep wall texture: Moderately muricate shell porosity: Finely Perforate: 1-2.5µm
umbilical or test sutures: Weakly depressed final-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:

Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested
Histogram - Neptune occurrence data from DSDP and ODP proceedings. Pale shading <50 samples in time bin. Interpret with caution & read these notes
Taxon plotted: Morozovella edgari, synonyms included - Globorotalia edgari; Morozovella edgari;
See also space-time plot :: Samples map :: Parent: Morozovella

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

References:

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: 10-12-2024

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test outline:	Lobate	chamber arrangement:	Trochospiral	edge view:	Inequally biconvex	aperture:	Umbilical-extraumbilical
sp chamber shape:	Crescentic	coiling axis:	Low	periphery:	Muricocarinate	aperture border:	N/A
umb chbr shape:	Subtriangular	umbilicus:	Narrow	periph margin shape:	Subangular	accessory apertures:	None
spiral sutures:	Flush	umb depth:	Deep	wall texture:	Moderately muricate	shell porosity:	Finely Perforate: 1-2.5µm
umbilical or test sutures:	Weakly depressed	final-whorl chambers:	5-6	N.B. These characters are used for advanced search. N/A - not applicable