Morozovella crater


Classification: pf_cenozoic -> 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 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: 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 - Eocene Atlas, chap. 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: 18-9-2018

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