Morozovella caucasica


Classification: pf_cenozoic -> Truncorotaloididae -> Morozovella -> Morozovella caucasica
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 caucasica (Glaessner 1937)
Rank: Species
Basionym: Globorotalia aragonensis caucasica
Synonyms:
Taxonomic discussion: There exists a variety of opinions on the phylogenetic affinities of this taxon which may be summarized as follows:
1. Although Glaessner (1937) clearly distinguished between his new taxon caucasica (early Eocene) and velascoensis Cushman (late Paleocene), the two forms were frequently confused in the literature (see
Subbotina, 1953 and El Naggar,1966, for example) as well as aragonensis and caucasica (identified as velascoensis; Subbotina, 1947; see Subbotina, 1953, p. 216). It was Reiss (1957; see also Blow, 1979) who provided clear differentiation of the two morphotypes on the basis of morphology and stratigraphic distribution. Indeed, one of us (WAB) pointed out this differentiation to Subbotina during a visit to VNIGRI (St. Petersburg) in 1958 and by the late 1950s Subbotina had incorporated the distinction between the two as shown by the correct identification of caucasica in the Soviet Treatise on Paleontology (Bykova and others, 1959).
2. Hillebrandt (1962) included crater Finlay and formosa Bolli in the synonomy of caucasica and considered it to have evolved from G. (T.) aequa simulatilis (see Berggren and Norris, 1997, p. 78 for a discussion of the probable/possible taxonomic affinities of the late Paleocene taxon simulatilis).
3. The holotype of Globorotalia crater Finlay is a 5-chambered morphotype similar in several respects to caucasica. Hornibrook (1958) drew attention to the “wide umbilicus surrounded by strongly muricate (not true spines) distal ends of chambers” as characteristic of crater. Jenkins (1971) considered M. caucasica a subspecies of crater and to differ only in the number of chambers ( 6-8 vs. 5) from the latter. Like Hillebrandt (1962), Jenkins (1971) considered formosa a junior synonym of crater.
4. Stainforth and others (1975) considered that crater is possibly a “highly ornamented member of the Globorotalia formosa formosa plexus and G. caucasica is a homeomorph originating from Globorotalia aragonensis with which it is linked by transitional forms”. In support of this view Stainforth and others (1975) observed that in New Zealand G. crater is used to delineate a zone which extends over/correlates with the G. formosa formosa, G. aragonensis and G. pentacamerata Zones, that is, a zone which extends below the base of the typical 6-8 chambered caucasica. 5. Blow (1979) extended these views in separating crater (5-chambered) and caucasica (6-8 chambered; see also Fleisher, 1974, pl. 14, fig. 2 who illustrated a morphotype with apparently 9 or 10 chambers from Zone P11 of the Indian Ocean) on the basis of chamber number and the narrower umbilicus of crater. He asserted that crater lies much closer to the caucasica end of the lensiformis-crater -caucasica lineage than it does to the ancestral lensiformis morphotype, a view with which we can readily agree. Thus, Blow (1979) considered crater as a form transitional between lensiformis and caucasica with typical 5-chambered morphotypes extending into horizons as high as Zone P10 (middle Eocene). Morozovella twisselmanni (Mallory) was considered a junior synonym of crater as well. However, Blow (1979) also illustrated several morphotypes which he attributed to crater but which also bear a close resemblance to formosa Bolli: 5-6 chambers, narrow umbilicus, absence of circumumbilical muricate ornament ( see for instance forms which he considered typical of crater by comparison with paratypes of crater; Blow, 1979, pl. 138, figs. 4-8).
6. Several authors have considered a phylogenetic relationship between aragonensis and caucasica more likely (Fleisher, 1974; Berggren 1977; Toumarkine and Luterbacher, 1985). Our own studies suggest that caucasica is, indeed, more closely related to crater and that it represents the end member of the subbotinae -lensiformis-crater -caucasica lineage, whereas aragonensis is the end member of a divergent M. subbotinae -lensiformis -aragonensis lineage. [Berggren & Pearson 2006]

Catalog entries: Globorotalia aragonensis caucasica;

Type images:

Distinguishing features: This taxon is characterized by having a strongly planoconical test with 6-8 (less commonly 5 at one extreme and 9-10 at the other) chambers in the final whorl, a large open and deep umbilicus whose everted circumumbilical chamber margins are strongly ornamented by fused muricae. It is strongly homeomorphic with M. velascoensis from the late Paleocene-early Eocene (Zone P3b-E2), but M. velascoensis s.s. may be distinguished by its (generally) somewhat larger size, higher conical angle and more pronounced circumumbilical ornament of everted chamber shoulders (tips).

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 taxon is characterized by having a strongly planoconical test with 6-8 (less commonly 5 at one extreme and 9-10 at the other) chambers in the final whorl, a large open and deep umbilicus whose everted circumumbilical chamber margins are strongly ornamented by fused muricae. It is strongly homeomorphic with M. velascoensis from the late Paleocene-early Eocene (Zone P3b-E2), but M. velascoensis s.s. may be distinguished by its (generally) somewhat larger size, higher conical angle and more pronounced circumumbilical ornament of everted chamber shoulders (tips). [Berggren & Pearson 2006]

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

Test morphology: Test subcircular, moderately lobulate peripheral outline, planoconvex; chambers triangular on umbilical side, trapezoidal to subquadrate on spiral side as a function of degree of curvature of intercameral sutures; wall surface normal perforate, nonspinose; muricae strongly developed on circumumbilical collar; primary aperture a low umbilical-extraumbilical slit extending to peripheral margin; sutures depressed, straight, radial; umbilicus large, deep surrounded by steeply plunging circumumbilical chamber walls and surmounted by thickly ornamented circumumbilical collar of fused muricae which rim the everted margins of the chambers; in spiral view 15-18 chambers arranged in approximately 3 whorls; early chambers slightly raised above test surface; gradual increase in chamber size throughout; muricate sutures strongly curved, flush with/slightly elevated above test surface; in edge view umbilicoconvex; spiral side flat or nearly so; strongly muricate/beaded keel. [Berggren & Pearson 2006]

Size: Holotype dimension(s): not given; range given: 0.4-0.6 mm (diameter). [Berggren & Pearson 2006]

Character matrix

test outline:Subcircularchamber arrangement:Trochospiraledge view:Planoconvexaperture:Umb.-extraumbilical
umb chamber shape:Subtriangularcoiling axis:Highperiphery:Single keelaperture border:N/A
sp chbr shape:Trapezoidalumbilicus:Wideperiph 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:0.4-0.6width mm:breadth mm:
final-whorl chambers:5.0-9.0

Biogeography and Palaeobiology


Geographic distribution: Widely distributed in (sub)tropical-Tethyan regions; particularly common in the Aquitaine Basin (France), the Indo-Pacific region, among others. [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 taxon is the end member of the M. subbotinae -lensiformis-crater -caucasica lineage and does not appear to have left any
descendants. It is strongly homeomorphic with, but unrelated in terms of lineal descent to, M. velascoensis. [Berggren & Pearson 2006]

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

Biostratigraphic distribution

Geological Range:
Notes: Zone E6 to Zone E8. [Berggren & Pearson 2006]
Last occurrence (top): in mid part of E8 zone (50% up, 44.8Ma, in Lutetian stage). Data source: Berggren & Pearson (2006) f11.1
First occurrence (base): at base of E6 zone (0% up, 50.7Ma, 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. 354

References:

Berggren, W.A. & Norris, R.D., (1997). Biostratigraphy, phylogeny and systematics of Paleocene trochospiral planktonic foraminifera. Micropaleontology, Supplement 1, 43: 1-116.

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.

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.

Fleisher, R.L., (1974). Cenozoic planktonic foraminifera and biostratigraphy, Arabian Sea, Deep Sea Drilling Project, Leg 23A. Initial Reports of the Deep Sea Drilling Project, 23: 1001-1072.

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.

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.

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.

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.

Reiss, Z., (1957). Notes On Foraminifera From Israel: 1. Remarks on Truncorotalia aragonensis caucasica (Glaessner). Bulletin Research Council Of Israel (Reprinted In Israel Geological Survey Bulletin, No9, I-III), 6B: 239-241.

Toumarkine, M. & Luterbacher, H., (1985). Paleocene and Eocene planktic foraminifera. Plankton StratigraphyCambridge Univ. Press, Cambridge, 87-154 pp.


logo

Morozovella caucasica compiled by the pforams@mikrotax project team viewed: 18-9-2018

Taxon Search:
Advanced Search
Short stable page link: http://mikrotax.org/pforams/index.php?id=100193Go to Archive.is to create a permanent copy of this page - citation notes



Comments (0)

No comments yet. Be the first!

Add Comment

* Required information
1000
Captcha Image
Powered by Commentics