pforams@mikrotax - Morozovella lensiformis

Citation: Morozovella lensiformis (Subbotina 1953)

Basionym: Globorotalia lensiformis

Synonyms:

Globorotalia lensiformis Subbotina, 1953:214, pl. 18: figs. 4a-c (holotype) and 5a-c [lower Eocene Zone of conical globorotaliids, Foraminiferal Beds, Unit F1, Nal’chik, Khieu River section, North Caucasus].—Luterbacher, 1964:673, text-figs. 74a-c [topotype from Zone of conical globorotaliids, Khieu River section, northern Caucasus, determined by N. N. Subbotina, fide Luterbacher].— Samuel, 1972:192, 193, pl. 49: figs. 3-4c [middle Eocene, Borehole Sr-1, Bakony Mountains, Hungary]; pl. 51: figs. 6a-b; 7a-b [Borehole Ot-69, Bakony Mountains, Hungary].—Stainforth and others, 1975:200, text-figs. 1a-2c (reillustrated from Subbotina, 1953); 3-7 [lower Eocene G. formosa formosa Zone, Lodo Fm., California].
Globorotalia (Truncorotalia) lensiformis Subbotina.—von Hillebrandt, 1962:136, pl. 13, figs. 12a-13c [Zone G, Reichenhall-Salzburg Basin, Austria/Germany].
Morozovella lensiformis (Subbotina).—Berggren, 1971, pl. 5: figs. 18-20 [Zone P6b, DSDP Hole 20C, South Atlantic Ocean].—Snyder and Waters, 1985:460, pl. 9: figs. 1, 3 [Zone P6b, DSDP Hole 548A, North east Atlantic Ocean].—Warraich and others, 2000:293, fig. 17. 7-9 [Zone P7, Dungan Fm., Rakhi Nala section, Sulaiman Range, Pakistan].—Warraich and Ogasawara, 2001:40, figs. 10. 1-3 [Zone P7, Dungan Fm., Rakhi Nala section, Sulaiman Range, Pakistan].
Globorotalia (Morozovella) lensiformis Subbotina.—Blow, 1979:1003-1005, pl. 125: figs. 6-9; pl. 126: figs. 1-3; pl. 128: figs. 1-9; pl. 129: figs. 1-3 [Zone P8a, DSDP Hole 47.2, Shatsky Rise, northwest Pacific Ocean]; pl. 134: fig. 7 and pl. 134: fig. 1 [Zone P8b, DSDP Hole 47.2, Shatsky Rise, northwest Pacific Ocean]; pl. 251: fig. 5 [lower Eocene, Region de Belu, France].
Globorotalia nartanensis Shutskaya, 1956:96-98, pl. 4: figs. 2a-c [G. subbotinae Zone, Cherkessk Horizon, Nal’chik, central northern Caucasus, former Soviet Union].
Globorotalia californica Smith, 1957:190, pl. 28: figs. 22a-23c [Vine Hill Sandstone, Selby, Contra Costa County, California].—Mallory, 1959:253, pl. 38: figs. 4a-c [lower Bulitian Stage, Lower Lodo Fm., Media Agua Creek, California]. [The name Globorotalia californica Smith 1957 is a junior homonym of Globorotalia californica Cushman and Todd 1948, which may be a praeglobotruncanid from California; see Berggren, 1977, p. 243.]
Globorotalia dolabrata Jenkins, 1966:1113, pl. 10: figs. 104-112 (holotype) [lower Eocene M. crater Zone, upper part of Waipawan Stage, Middle Waipara River section, North Island, New Zealand].
Globorotalia (Morozovella) dolabrata Jenkins.—Jenkins, 1971:104, pl. 104: figs. 233-235 (holotype refigured); figs. 236 -238, 239-241 (paratypes) [lower Eocene M. crater Zone, upper part of Waipawan Stage, Middle Waipara River section, North Island, New Zealand].
Globorotalia (Morozovella) aequa dolabrata Jenkins.—Blow, 1979:981, pl.125: figs. 3-5 and pl. 127: fig. 8 [Zone P8a, DSDP Hole 47.2, Shatsky Rise, northwest Pacific Ocean]; pl. 133: figs. 1-6 [Zone P8b, DSDP Hole 47.2, Shatsky Rise, northwest Pacific Ocean]; pl. 137: figs. 2-9 [Zone P8b, DSDP Hole 20C, South Atlantic Ocean]; pl. 251: figs. 6 and 7 [Zone of conical globorotaliids, Novogeorgii Fm., Kuban River section, northern Caucasus].
Globorotalia lensiformis Subbotina subsp. carpatica Samuel, 1972, p. 127-128, pl. 36, figs. 1a-2c (holotype) [middle Eocene upper Turborotalia (Acarinina) crassata densa Zone, Myjava brick kiln, north east of Bratislava, Czechoslovakia].

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]

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.

Description

This taxon is characterized by its subquadrate, involute, biconvex test with narrow umbilicus; test covered by moderately to densely distributed, blunt muricae obscuring, in some instances, the peripheral muricocarina; 4-4½ chambers in last whorl. Later forms exhibit transitional features to plano-convex, multicameral M. aragonensis. [Berggren & Pearson 2006]

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]

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]

Biogeography and Palaeobiology

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)

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)

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]

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

Primary source for this page: Berggren & Pearson 2006 - Eocene Atlas, chap. 11, p. 366

References:

Berggren, W. A. & Pearson, P. N. (2006a). Taxonomy, biostratigraphy, and phylogeny of Eocene Morozovella. In, Pearson, P. N., Olsson, R. K., Hemleben, C., Huber, B. T. & Berggren, W. A. (eds) Atlas of Eocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication . 41(Chap 11): 343-376. gs O

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

Blow, W. H. (1979). The Cainozoic Globigerinida: A study of the morphology, taxonomy, evolutionary relationships and stratigraphical distribution of some Globigerinida (mainly Globigerinacea). E. J. Brill, Leiden. 2: 1-1413. gs

Boersma, A., Premoli Silva, I. & Shackleton, N. J. (1987). Atlantic Eocene planktonic foraminiferal paleohydrographic indicators and stable isotope paleoceanography. Paleoceanography. 2: 287-331. gs

Cushman, J. A. & Todd, R. (1948). A foraminiferal fauna from the New Almaden district, California. Contributions from the Cushman Laboratory for Foraminiferal Research. 24: 90-98. gs

Hillebrandt, A. , von (1962). Das Paleozän und seine Foraminiferenfauna im Becken von Reichenhall und Salzburg. Abhandlungen Bayerischen Akademie der Wissenschaften. 108: 1-182. gs

Jenkins, D. G. (1966b). Planktonic foraminiferal zones and new taxa from the Danian to lower Miocene of New Zealand. New Zealand Journal of Geology and Geophysics. 8 [1965](6): 1088-1126. gs

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

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

Mallory, V. S. (1959). Lower Tertiary biostratigraphy of the California Coast Ranges. American Association of Petroleum Geologists, Tulsa, Oklahoma. 1-416. gs

Samuel, O. (1972b). Planktonic Foraminifera from the Eocene in the Bakony mountains (Hungary). Zborník geologických vied, séria Západné Karpaty. 17: 165-206. gs

Smith, B. Y. (1957). Lower Tertiary foraminifera from Contra Costa county, California. University of California Publications in Geological Sciences. 32(3): 127-242. gs

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. gs

Stainforth, R. M., Lamb, J. L., Luterbacher, H., Beard, J. H. & Jeffords, R. M. (1975). Cenozoic planktonic foraminiferal zonation and characteristics of index forms. University of Kansas Paleontological Contributions, Articles. 62: 1-425. gs O

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

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

test outline:	Subquadrate	chamber arrangement:	Trochospiral	edge view:	Equally biconvex	aperture:	Umbilical-extraumbilical
sp chamber shape:	Petaloid	coiling axis:	Low	periphery:	Single keel	aperture border:	N/A
umb chbr shape:	Inflated	umbilicus:	Narrow	periph margin shape:	Subangular	accessory apertures:	None
spiral sutures:	Moderately depressed	umb depth:	Deep	wall texture:	Coarsely muricate	shell porosity:	Finely Perforate: 1-2.5µm
umbilical or test sutures:	Strongly depressed	final-whorl chambers:	4-4.5	N.B. These characters are used for advanced search. N/A - not applicable

Morozovella lensiformis

Taxonomy

Description

Biogeography and Palaeobiology

Biostratigraphic distribution

References:

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