Morozovella aequa


Classification: pf_cenozoic -> Truncorotaloididae -> Morozovella -> Morozovella aequa
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 aequa (Cushman and Renz 1942)
Rank: Species
Basionym: Globorotalia crassata aequa
Synonyms:
Taxonomic discussion: This taxon has a complicated and intricate taxonomic history due, in no small part, to the (minor) morphologic variability (and resulting complex nomenclature) ascribed to this species (see discussion by Blow, 1979:975- 982). Cushman and Renz (1942) described a subquadrate, planoconvex, carinate morozovellid from the terminal Paleocene of Trinidad, which has come to serve as the central type of a plexus of late Paleocene to early Eocene forms generally linked by the features listed in the diagnosis above; however, we see little justification, or utility, in using these minor morphologic differences in distinguishing the forms listed in the synonymic list above. [Olsson et al. 1999]

Catalog entries: Globorotalia (Morozovella) aequa tholiformis;
Globorotalia aequa bullata;
Globorotalia crassata aequa;
Globorotalia lacerti;
Globorotalia loeblichi;
Globorotalia praenartanensis;

Type images:

Distinguishing features: Subquadrate, plano-convex, muricocarinate test with moderately lobulate peripheral outline and 4 (less commonly 5) chambers in last whorl; intercameral sutures on umbilical side straight, radial; raised, curved on spiral side; umbilicus narrow, bordered by low apertural slit which extends nearly to periphery; test surface generally covered with muricae, particularly on umbilical shoulder and along peripheral margin.

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: Subquadrate, plano-convex, muricocarinate test with moderately lobulate peripheral outline and 4 (less commonly 5) chambers in last whorl; intercameral sutures on umbilical side straight, radial; raised, curved on spiral side; umbilicus narrow, bordered by low apertural slit which extends nearly to periphery; test surface generally covered with muricae, particularly on umbilical shoulder and along peripheral margin. [Olsson et al. 1999]

Character matrix

test outline:Lobatechamber arrangement:Trochospiraledge view:Planoconvexaperture:-
umb chamber shape:Subtriangularcoiling axis:Moderate-highperiphery:Muricocarinateaperture border:N/A
sp chbr shape:Petaloidumbilicus:Narrowperiph margin shape:Subangularaccessory apertures:None
umbilical or test sutures:Moderately depressedumb depth:Deepwall texture:Moderately muricateshell porosity:Finely Perforate: 1-2.5µm
spiral sutures:Raised muricatediameter mm:width mm:-breadth mm:-
final-whorl chambers:4.0-5.0

Biogeography and Palaeobiology


Geographic distribution: Morozovella aequa is a geographically widespread species, having been recorded from areas circumscribed by latitudes 50°N (Goban Spur, northeastern Atlantic Ocean; Snyder and Waters, 1985) and 50°S (Falkland Plateau; Tjalsma, 1977); it occurs as far south as nearly 60° (Kerguelen Plateau; Berggren, 1992) during the brief early Eocene (Zone P6) temporal excursion of (sub)tropical morozovellids. [Olsson et al. 1999]
Aze et al. 2011 summary: Cosmopolitan; based on Olsson et al. (1999)

Isotope paleobiology: Morozovella aequa has more positive ∂13C and more negative ∂18O than Subbotina and Globanomalina and a similar isotopic signature to coexisting morozovellids, such as M. velascoensis (Lu and Keller, 1996; Berggren and Norris, 1997). [Olsson et al. 1999]
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): Lu & Keller (1996); Berggren & Norris (1997)

Phylogenetic relations: Morozovella aequa evolved from M. apanthesma through concomitant reduction in the number of chambers and the development of both more involute coiling (resulting in a more closed umbilicus) and a peripheral muricocarina. We have observed this transition both in our material and particularly at DSDP Site 384, where it occurs at the base of Zone P4c together with the appearance of various acarininid taxa of the soldadoensis and primitiva !coalingensis plexus in the younger part of Chron C25r. We have not found this form in lower parts of the stratigraphic record (cf. Blow, 1979; Lu and Keller, 1995). [Olsson et al. 1999]

Most likely ancestor: Morozovella apanthesma - at confidence level 4 (out of 5). Data source: Olsson et al. (1999) f5a.

Biostratigraphic distribution

Geological Range:
Notes: Zone P4c to Zone P7. [Olsson et al. 1999]
Last occurrence (top): at top of E5 zone (100% up, 50.7Ma, in Ypresian stage). Data source: Olsson et al. (1999) f5a
First occurrence (base): at base of P4c subzone (0% up, 57.8Ma, in Thanetian stage). Data source: Olsson et al. (1999) f5a

Plot of occurrence data:

Primary source for this page: Olsson et al. 1999 - Atlas of Paleocene Planktonic Foraminifera, p. 57

References:

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.

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.

Bolli, H.M., (1957). The genera Globigerina and Globorotalia in the Paleocene-Lower Eocene Lizard Springs Formation of Trinidad. In: Loeblich, A.R., Jr. et al. (Editors), Studies in Foraminifera, U.S. National Museum Bulletin 215. U.S. Government Printing Office, Washington, D.C., pp. 61-82.

Cushman, J.A. & Bermudez, P.J., (1949). Some Cuban species of Globorotalia. Contributions from the Cushman Laboratory for Foraminiferal Research, 25: 26-45.

Cushman, J.A. & Renz, H.H., (1942). Eocene, Midway, foraminifera from Soldado Rock, Trinidad. Contributions from the Cushman Laboratory for Foraminiferal Research, 18: 1-14.

Cushman, J.A. & Renz, H.H., (1946). The foraminiferal fauna of the Lizard Springs formation of Trinidad, British West Indies. Cushman Laboratory for Foraminiferal Research Special Publication, 18: 1-48.

El-Naggar, Z.R., (1966). Stratigraphy and planktonic foraminifera of the Upper Cretaceous-Lower Tertiary succession in the Esna-Idfu region, Nile Valley, Egypt, U. A. R. Bulletin of the British Museum (Natural History) Geology, supplement 2: 1-291.

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., (1965). Planktonic Foraminiferal zones and new taxa from the Danian to lower Miocene of New Zealand. New Zealand Journal of Geology and Geophysics, 8(6): 1088-1126.

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

Loeblich, A.R. & Tappan, H., (1957). Planktonic foraminifera of Paleocene and early Eocene Age from the Gulf and Atlantic coastal plains. In: Loeblich, A.R., Jr. et al. (Editors), Studies in Foraminifera, U.S. National Museum Bulletin 215. U.S. Government Printing Office, Washington, D.C., pp. 173-198.

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

McGowran, B., (1968). Reclassification of Early Tertiary Globorotalia. Micropaleontology, 14: 179-198.

Olsson, R.K.; Hemleben, C.; Berggren, W.A. & Huber, B.T., (1999). Atlas of Paleocene Planktonic Foraminifera. Smithsonian Contributions to Paleobiology, 85. Smithsonian Institution Press, Washington, DC, 1-252 pp.

Shutskaya, E.K., (1956). Stratigraphy of the lower horizons of the Paleogene of the central Precaucasus according to the foraminifera. Akad Nauk SSSR, Inst Geol Nauk, Trudy, vypusk 164, Geol. Ser., 71: 3-119.

Stott, L.D. & Kennett, J.P., (1990). The Paleoceanographic and Paleoclimatic signature of the Cretaceous/Paleogene boundary in the Antarctic: Stable isotopic results from ODP Leg 113. Proceedings of the Ocean Drilling Program, Scientific Results, 113: 829-848.

Tjalsma, R.C., (1977). Cenozoic Foraminifera from the South Atlantic, DSDP Leg 36. Initial Reports of the Deep Sea Drilling Project, 36: 493-518.


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Morozovella aequa compiled by the pforams@mikrotax project team viewed: 22-9-2018

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