Morozovella crater


Classification: pf_cenozoic -> muricate non-spinose -> Truncorotaloididae -> Morozovella -> Morozovella crater
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 crater (Finlay 1939)
Rank: Species
Basionym: Globorotalia crater Finlay 1939
Synonyms:
Taxonomic discussion: NB. The discussion below has been corrected from that given in Berggren & Pearson (2006) since they incorrectly stated that G. crater was nomen nudum until Hornibrook (1958) illustrate the holotype. In fact illustration of a holotype is only mandatory under the ICZN for taxa described after 1999 and Finlay's original description was valid. [JR Young 2017]

In erecting the new species Globorotalia crater Finlay (1939a) gave a brief description but no formal illustration(s).  Specimens figured by Finlay (1939b, pl. 29: figs. 157, 162, 163) are from older strata than the type level and are of a different species (Hornibrook, 1958). The first proper clarification of M. crater is by Hornibrook (1958, p. 33, pl. 1, figs. 3-5) in which the holotype specimen is illustrated and a more thorough description given; see also Berggren, 1977, (p. 245, 246). Jenkins (1971, p. 103) and Blow (1979, p. 996) have presented extensive discussion of this taxon and suggested that it is either a junior synonym (Jenkins, 1971) or a pene-contemporaneous homeomorph (Blow, 1979) of M. formosa. We have found in the course of our work that crater exhibits a general test shape closer to that of aragonensis (subcircular, weakly lobulate periphery) than formosa (moderately to strongly lobulate periphery and early vorticiform spiral intercameral sutures). [Berggren & Pearson 2006]

Catalog entries: Globorotalia (Morozovella) gorrondatxensis;
Globorotalia aragonensis twisselmanni;
Globorotalia crater;

Type images:

Distinguishing features: 4½ to 5 essentially equidimensional chambers in last whorl, thickened circumumbilical rim of elevated chamber shoulders, strongly limbate sutures on spiral side.

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: 4½ to 5 essentially equidimensional chambers in last whorl, thickened circumumbilical rim of elevated chamber shoulders, strongly limbate sutures on spiral side. [Berggren & Pearson 2006]

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

Test morphology: Plano-convex test with lobulate outline, ornamented with well developed muricocarina; 4½ to 5 essentially equidimensional chambers in last whorl; umbilical intercameral sutures weakly curved to radial; sutures on spiral side curved, limbate, heavily ornamented (beaded); umbilicus deep and relatively wide, rimmed by everted, thickened circumumbilical rim of elevated chamber shoulders (tips); in edge view distinctly plano-convex.; aperture a low, interiomarginal, umbilical-extraumbilical slit with thin lip. [Berggren & Pearson 2006]

Size: Maximum diameter of holotype: 0.53 mm (Jenkins, 1971, p. 104). [Berggren & Pearson 2006]

Character matrix

test outline:Lobatechamber arrangement:Trochospiraledge view:Planoconvexaperture:-
umb chamber shape:Subtriangularcoiling axis:Highperiphery:Muricocarinateaperture border:Thin lip
sp chbr shape:Crescenticumbilicus:Wideperiph margin shape:Subangularaccessory apertures:None
umbilical or test sutures:Raised muricateumb depth:Deepwall texture:Moderately muricateshell porosity:Finely Perforate: 1-2.5µm
spiral sutures:Raised beadeddiameter mm:0.53width mm:breadth mm:
final-whorl chambers:4.5-5.0

Biogeography and Palaeobiology


Geographic distribution: Widely distributed in (sub)tropical areas of Atlantic, Mediterranean/ Tethyan, Pacific Oceans and austral regions. [Berggren & Pearson 2006]
Aze et al. 2011 summary: Low latitudes; based on Berggren & Pearson (2006)

Isotope paleobiology: No data available. [Berggren & Pearson 2006]
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 form evolved from M. lensiformis and evolved into M. caucasica. [Berggren & Pearson 2006]

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

Biostratigraphic distribution

Geological Range:
Notes: Zone E4 to Zone E9. [Berggren & Pearson 2006]
Last occurrence (top): in upper part of E9 zone (70% up, 43.4Ma, in Lutetian stage). Data source: Berggren & Pearson (2006) f11.1
First occurrence (base): in lower part of E4 zone (40% up, 53.8Ma, in Ypresian stage). Data source: Berggren & Pearson (2006) f11.1

Plot of occurrence data:

Primary source for this page: Berggren & Pearson 2006 - Atlas of Eocene Planktonic Foraminifera, chapter 11, p. 358

References:

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

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.

Finlay, H.J., (1939). New Zealand foraminifera: Key species in stratigraphy - no. 2. Transactions of the Royal Society of New Zealand, 69(1): 89-128.

Hornibrook, N.d.B., (1958). New Zealand Upper Cretaceous and Tertiary foraminiferal zones and some overseas correlations. Micropaleontology, 4: 25-38.

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

Mallory, V.S., (1959). Lower Tertiary biostratigraphy of the California Coast Ranges. American Association of Petroleum Geologists, Tulsa, Oklahoma, 416 pp.

Pearson, P.N. & others, (2004). Paleogene and Cretaceous sediment cores from the Kilwa and Lindi areas of coastal Tanzania: Tanzania Drilling Project Sites 1–5. Journal of African Earth Sciences, 39: 25-62.


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

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