Morozovella marginodentata


Classification: pf_cenozoic -> Truncorotaloididae -> Morozovella -> Morozovella marginodentata
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.,

Taxonomy

Citation: Morozovella marginodentata (Subbotina 1953)
Rank: Species
Basionym: Globorotalia marginodentata
Synonyms:
Taxonomic discussion: Placement of this taxon is extremely difficult. “Typical” specimens of marginodentata are denoted by their marginally compressed/scalloped chambers and thickly muricate periphery. However, in most early Eocene (sub)tropical fossil assemblages intergradation of these morphologies with “typical” morphologies of M. gracilis and M. subbotinae exist. Blow (1979, p. 1025, 1026) drew attention to the development of marginodentate ornament on both a subbotinae and gracilis morphotype, interpreted the marginodentate forms as “extreme phenotypes developed under particular environmental conditions...” and observed that “the ‘marginodentate’ forms appear to occur only in areas of high biotic productivity”. He chose to view these ecophenotypes nomenclatorially as extreme forms of subbotinae (sensu stricto) and denoted them as G. (M.) subbotinae forma marginodentata. Berggren (1971, p. 76) expressed similar views in suggesting that marginodentata may be an ecophenotype of gracilis. We retain the name marginodentata here for forms possessing the distinctly thick and broad peripheral muricocarina. [Berggren & Pearson 2006]

Catalog entries: Globorotalia marginodentata;
Truncorotalia marginodentata aperta;

Type images:

Distinguishing features: Morphotype, with pronounced peripheral compression of the chambers on the umbilical side and a thick muricocarina formed form long muricae.

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: This morphotype, while exhibiting characters apparently intermediate to other, closely related forms, is characterized by the markedly pronounced peripheral compression of the chambers on the umbilical side which are bordered/ rimmed by a thick and broad peripheral muricocarina formed by the fusion of inordinately large/thick and long muricae. [Berggren & Pearson 2006]

Wall type: Densely muricate on both sides, nonspinose, normal perforate. [Berggren & Pearson 2006]

Test morphology: Low trochospiral, biconvex, oval to subcircular test with lobulate, thick and strongly fimbriate muricocarina; chambers on umbilical side moderately inflated, depressed towards periphery; flat on spiral side; 4.5 - 5 chambers in last whorl, (sub)triangular, compressed along peripheral margin, rising gradually towards umbilicus; sutures straight to weakly recurved, radial, depressed; aperture a low, umbilical-extraumbilical arch or slit extending towards, but not to, the periphery; umbilicus narrow, deep; in spiral view approximately 10-12 chambers in 2.5 whorls; early chambers heavily muricate and elevated above test surface; chambers lens-shaped to semicircular, intercameral sutures curved, strongly muricate, elevated above test surface; scalloped peripheral muricocarinate periphery characterized by dense concentration of conical or long slender muricae and the fusion/coalescence of muricae; in edge view low to moderately biconvex; early chambers elevated above later whorl(s); low to medium conical angle (< 45° to ~75°). [Berggren & Pearson 2006]

Size: Holotype Diameter: 0.43 mm; thickness/width: 0.24 mm (Subbotina, 1953, p. 213) [Berggren & Pearson 2006]

Character matrix

test outline:Subcircularchamber arrangement:Trochospiraledge view:Equally biconvexaperture:-
umb chamber shape:Subtriangularcoiling axis:Lowperiphery:Muricocarinateaperture border:N/A
sp chbr shape:Petaloidumbilicus:Narrowperiph margin shape:Subangularaccessory apertures:None
umbilical or test sutures:Moderately depressedumb depth:Deepwall texture:Coarsely muricateshell porosity:Finely Perforate: 1-2.5µm
spiral sutures:-final-whorl chambers:4.5-5.0

Biogeography and Palaeobiology


Geographic distribution: Widely distributed in (sub)tropical regions (Caribbean, Atlantic Ocean, Indo-Pacific region, North Caucasus) [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 morphotype is closely related to the subbotinae-gracilis group. It probably evolved from M. subbotinae and does not appear to have left any descendants. [Berggren & Pearson 2006]

Most likely ancestor: Morozovella subbotinae - at confidence level 3 (out of 5). Data source: Berggren & Pearson (2006) f11.1.

Biostratigraphic distribution

Geological Range:
Notes: Zone P5 to Zone E5. [Berggren & Pearson 2006]
Last occurrence (top): in mid part of E5 zone (50% up, 51.6Ma, in Ypresian stage). Data source: Berggren & Pearson (2006) f11.1
First occurrence (base): in upper part of P5 zone (80% up, 56.2Ma, in Thanetian 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. 368

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 Allen Press, Lawrence, Kansas, pp. 343-376.

Berggren, W.A., (1971). Paleogene planktonic foraminiferal faunas on Legs I-IV (Atlantic Ocean) JOIDES Deep Sea Drilling Program: a synthesis. In: Farinacci, A. (Editor), Proceedings of the II Planktonic Conference, Roma 1970. Edizioni Tecnoscienza, Rome, pp. 57-77.

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.

Cushman, J.A., (1925). Some new foraminifera from the Velasco shale of Mexico. Contributions from the Cushman Laboratory for Foraminiferal Research, 1(6): 18-23.

Glaessner, M.F., (1937). Studien über foraminiferen aus der kreide und dem Tertiär des Kaukasus. I. Die foraminiferen der ältesten Tertiärschichten des Nordwest-Kaukasus. Problemy Paleontologii, Paleontologicheskay Laboratoriya Moskovskogo Gosudarstvennogo Universiteta, 2-3: 349-410.

Glaessner, M.F., (1937). Planktonforaminiferen aus der Kreide und dem Eozän und ihre stratigraphische Bedeutung. Etyudy po Mikropaleontologiy, Paleontologicheskaya Laboratoriya Moskovskogo Gosudarstvennogo Universiteta. [Studies in Micropaleontology, Publications of the Laboratory of Paleontology, Moscow University], 1(1): 27-46.

Gohrbandt, K., (1963). Zur Gliederung des Palaeogen im Helvetikum nordlich Salzburg nach planktonischen Foraminiferen. Mitt Geol Ges, Wien, 56(1): 63.

Hillebrandt von, A., (1962). Das Paleozän und seine Foraminiferenfauna im Becken von Reichenhall und Salzburg. Bayerische Akademie der Wissenschaften Mathematisch-Naturwissenschaftliche Klasse, Abhandlungen, Neue Folge, 108: 1-182.

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

Luterbacher, H.P., (1964). Studies in some Globorotalia from the Paleocene and Lower Eocene of the Central Apennines. Eclogae Geologicae Helvetiae, 57: 631-730.

Luterbacher, H.P., (1975). Paleocene and Early Eocene planktonic foraminifera Leg 32, Deep Sea Drilling Project. Initial Reports of the Deep Sea Drilling Project, 32: 725-728.

Luterbacher, H.P., (1975). Planktonic Foraminifera of the Paleocene and Early Eocene, Possagno Section. Schweizerische Palaontologische Abhandlungen, 97: 57-67.

Snyder, S.W. & Waters, V.J., (1985). Cenozoic planktonic foraminiferal biostratigraphy of the Goban Spur Region, Deep Sea Drilling Project Leg 80. Initial Reports of the Deep Sea Drilling Project, 80: 439-472.

Subbotina, N., (1953). Foraminiferes fossiles d'URSS Globigerinidae, Globorotaliidae, Hantkeninidae. Bureau de Recherches Geologiques et Minieres, 2239: 1-144.

Warraich, M.Y. & Ogasawara, K., (2001). Tethyan Paleocene-Eocene planktic foraminifera from the Rakhi Nala and Zinda Pir land sections of the Sulaiman Range, Pakistan. Science Reports of the Institute of Geosciences, University of Tsukuba, Section B = Geological Sciences, 22: 1-59.

Warraich, M.Y.; Ogasawara, K. & Nishi, H., (2000). Late Paleocene to early Eocene planktic foraminiferal blostratigraphy of the Dungan Formation, Sulaiman Range, central Pakistan. Paleontological Research, 4(4): 275-301, 18 figures, 3 appendices.


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Morozovella marginodentata compiled by the pforams@mikrotax project team viewed: 16-11-2018

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