pforams@mikrotax - Morozovella lensiformis pforams@mikrotax - Morozovella lensiformis

Morozovella lensiformis

Classification: pf_cenozoic -> Truncorotaloididae -> Morozovella -> Morozovella lensiformis
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.


Citation: Morozovella lensiformis (Subbotina 1953)
taxonomic rank: Species
Basionym: Globorotalia lensiformis
Taxonomic discussion: Subbotina (1953, p. 214) described this taxon from the lower part of the Zone of conical globorotaliids (to which it was said to be essentially restricted = Zone E4-5 of this paper). She recognized its descendant affinities with the Globorotalia marginodentata and G. crassata ( =M. aequa -subbotinae group) and ancestral relationships with M. aragonensis, interpretations which have withstood the test of time, relatively unchanged. Shutskaya (1956) subsequently described the junior synonym Globorotalia nartanensis from essentially the same stratigraphic level and locality in the northern Caucasus and recognized its transitional features with aragonensis.
Blow (1979, p. 981) treated M. dolabrata (Jenkins) as the ancestor of M. lensiformis (Subbotina) (Blow, 1979, p. 1005). He distinguished the transition between the two on the following basis: an increase in tightness of coiling-mode and proportionate decrease in size of last chamber relative to earlier chambers and a relatively stronger recurvature of the spiral intercameral sutures and more tightly appressed chamber development in lensiformis. It is clear that Blow (1979) viewed dolabrata as morphogenetically transitional from aequa s.s. to lensiformis.
We view the two taxa as synonymous. Topotypes of dolabrata kindly sent to one of us (WAB) by D. Graham Jenkins exhibit a densely muricate test with 4-4½ chambers as in lensiformis. A (“buried”) muricocarina rims the test. While Jenkins (1966) indicated that a peripheral keel was developed only on the last chamber, his own figures belie this fact (Jenkins, 1966, text-fig. 106), and Blow (1979, p. 401, 982) pointed out that the presence or visibility of a peripheral muricocarina is a function of the acuteness of the peripheral margins of the chambers. In broadly rounded margins the peripheral muricae are only partially fused and coalesced and do not yield the same “morphology” as that seen when the peripheral muricocarinae fuse into a single band along the margin of a test with an acutely angled periphery. A buried keel is characteristic of lensiformis as well and is dependent upon preservation as well as degree of acuteness of the peripheral margin. Distinction between these two morphotypes by Blow (1979) appear to be based on differences of degree rather than kind and we see little purpose in their separation. The upper stratigraphic limit of Zone P10 accorded by Blow (1979, p. 1005) to lensiformis remains enigmatic. We have not found morphotypes resembling lensiformis at such stratigraphically high levels. [Berggren & Pearson 2006]

Catalog entries: Globorotalia lensiformis, Globorotalia californica Smith, Globorotalia lensiformis carpatica, Globorotalia nartanensis, Globorotalia dolabrata

Type images:

Distinguishing features:
Parent taxon (Morozovella): Test typically plano-convex, chambers strongly anguloconical.
Wall strongly pustulose (muricate) on parts of spire and umbilicus. Most species with muricocarina.

This taxon: Test subquadrate, involute, biconvex, with narrow umbilicus; covered by blunt muricae, often obscuring the peripheral muricocarina; 4-4½ chambers in last whorl.

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.


Test low trochospiral, subquadrate to subcircular, weakly lobulate, chambers moderately inflated on umbilical side; flat on spiral side except for initial chambers; surface densely covered by blunt/truncated muricae giving the test a granular/sugary texture; 4-4½ chambers visible in tight coil on umbilical side; primary aperture a low umbilical-extraumbilical slit extending to the periphery; sutures on umbilical side straight to slightly curved, slightly depressed; in spiral view 9-10 chambers in 2½ to 3 whorls [early chambers/ whorls elevated giving biconvex appearance and often obscured by muricate growth]; intercameral sutures moderately to strongly muricate and (re)curved yielding trapezoidal shaped chambers; weakly biconvex in edge view; moderately umbilico-convex peripheral muricocarina often obscured by fusion of muricae along margin. [Berggren & Pearson 2006]

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

Diameter: 0.40-0.55 mm; thickness: 0.25-0.30 mm (Subbotina, 1953, p. 214). [Berggren & Pearson 2006]

Character matrix
test outline:Subquadratechamber arrangement:Trochospiraledge view:Equally biconvexaperture:Umbilical-extraumbilical
sp chamber shape:Petaloidcoiling axis:Lowperiphery:Single keelaperture border:N/A
umb chbr shape:Inflatedumbilicus:Narrowperiph margin shape:Subangularaccessory apertures:None
spiral sutures:Moderately depressedumb depth:Deepwall texture:Coarsely muricateshell porosity:Finely Perforate: 1-2.5µm
umbilical or test sutures:Strongly depressedfinal-whorl chambers:4-4.5 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology

Geographic distribution

Relatively common in (sub)tropical areas; South Atlantic Ocean, Indo-Pacific, North Caucasus, among others. [Berggren & Pearson 2006]
Aze et al. 2011 summary: Low latitudes; based on Berggren & Pearson (2006)

Isotope paleobiology
Oxygen and carbon isotopes indicate a surface mixed layer habitat (Boersma and others, 1987). [Berggren & Pearson 2006]
Aze et al. 2011 ecogroup 1 - Open ocean mixed-layer tropical/subtropical, with symbionts. Based on very heavy _13C and relatively light _18O. Sources cited by Aze et al. 2011 (appendix S3): Boersma et al. (1987)

Phylogenetic relations
This taxon (probably) evolved from M. subbotinae and is the ancestor of both M. crater in Zone E4 and M. aragonensis at the base of Zone E5. [Berggren & Pearson 2006]

Most likely ancestor: Morozovella subbotinae - at confidence level 4 (out of 5). Data source: Berggren & Pearson (2006) f11.1.
Likely descendants: Morozovella aragonensis; Morozovella crater; plot with descendants

Biostratigraphic distribution

Geological Range:
Notes: Base of Zone E4 to Zone E6. [Berggren & Pearson 2006]
Last occurrence (top): in mid part of E6 zone (50% up, 50.4Ma, in Ypresian stage). Data source: Berggren & Pearson (2006) f11.1
First occurrence (base): at base of E4 zone (0% up, 54.6Ma, 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. 366


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

Berggren, W. A. (1977a). Atlas of Palaeogene Planktonic Foraminifera: some Species of the Genera Subbotina, Planorotalites, Morozovella, Acarinina and Truncorotaloides. In, Ramsay, A. T. S. (ed.) Oceanic Micropaleontology. Academic Press, London 205-300. gs

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

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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. 22: 1-59. gs

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, Tokyo. 4(4): 275-301, 218 figures, 273 aendices. gs


Morozovella lensiformis compiled by the pforams@mikrotax project team viewed: 16-6-2024

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