pforams@mikrotax - Morozovella occlusa

Citation: Morozovella occlusa (Loeblich and Tappan 1957)

Synonyms:

Discorbina simulatilis Schwager, 1883:120, pl. 29: fig. 15a-d [? Zone P4, Farafra Oasis, Egypt],
Globorotalia occlusa Loeblich and Tappan, 1957a: 191, pl. 55: fig. 3a-c [Zone P4, Vincentown Fm., New Jersey], pl. 64: fig. 3a-c [holotype, Zone P4, Velasco Shale, Tamaulipas, Mexico].—Luterbacher, 1964:690, text-figs. 112a-II 3c [Globorotalia velascoensis Zone, Velasco Fm., Ebano, eastern Mexico], text-fig. 114a-c [Globorotalia velacoensis Zone, Gubbio section, central Apennines, Italy].
Globorotalia crosswicksensis Olsson, 1960:47, pl. 10: figs. 7-9 [Zone P3b, Hornerstown Fm., New Jersey],
Globorotalia (Truncorotalia) velascoensis occlusa Loeblich and Tappan.— Hillebrandt, 1962:139, pl. 13: figs. 22, 24, 25 [Zone F = Zone P4/5 this paper], pl. 13: figs. 23, 26 [Zone D = Globorotalia pusilla pusilla Zone (upper part), Reichenhall-Salzburg Basin, Austro-German border].
Globorotalia (Morozovella) occlusa Loeblich and Tappan.—Jenkins, 1971:106, pl. 9: figs. 208-210 [Subbotina triloculinoides Zone, Waipawan Stage, Middle Waipara River section, New Zealand].—Blow, 1979:1007, pl. 90: figs. 7, 10 [lower part of Zone P4, DSDP Hole 21 A/3/6: 74-76 cm; South Atlantic Ocean], pl. 95: figs. 7-10, pl. 96: figs. 1-3 [Zone P5, sample FCRM. 1670, Lindi area, Tanzania], pl. 213: fig. 6. pl. 214: figs. 1-6, pl. 215: figs. 5, 6, pl. 103: figs. 4-6, pl. 108: figs. 9. 10 [Zone P6, lower part, DSDP Hole 20C/6/3: 76-78 cm; Brazil Basin. South Atlantic Ocean], pl. 118: figs. 1-7 [Zone P7, DSDP Hole 47.2/8/3: 83-85 cm; Shatsky Rise, northwestern Pacific Ocean].—Belford, 1984:9, pl. 17: figs. 6-14 [upper Paleocene, WABAG Sheet area, Papua, New Guinea].
Globorotalia (Morozovella) occlusa cf. occlusa Loeblich and Tappan.—Blow, 1979:1007, pl. 92: figs. 5, 6 [Zone P4, DSDP Hole 47.2/8/3: 83-85 cm; Shatsky Rise, northwestern Pacific Ocean].
Globorotalia (Morozovella) occlusa crosswickensis Olsson.—Blow, 1979:1011, pl. 88: figs. 1, 2, pl. 213: figs. 1,2 [upper part of Zone P3, DSDP Hole 47.2/10/1: 72-74 cm; Shatsky Rise, northwestern Pacific Ocean], pl. 90: figs. 3-6, 8, 9, pl. 213: figs. 3-5, pl. 215: figs. 1-4 [lower part of Zone P4, DSDP Hole 21 A/3/6: 74-76 cm; South Atlantic Ocean].
Morozovella simulatilis (Schwager).—Snyder and Waters, 1985:470, pl. 9: figs. 7-9 [Zone P4/5, DSDP Site 549/16/4: 57-60 cm; northeastern Atlantic Ocean]. [Olsson et al. 1999]

Taxonomic discussion: The enhanced, expanded concept of M. occlusa applied by Hillebrandt (1962) to include biconvex forms with 5-8 chambers is followed herein (see also Gohrbandt, 1963; Luterbacher, 1964; Samanta, 1970). Blow (1979) interpreted this form as a morphologically and phylogenetically advanced (descendant) form of M. crosswicksensis Olsson, which was said to generally lack the circumumbilical muricate coronet present in M. occlusa. The former was described from Zone P3b (Hornerstown Fm., New Jersey); the latter was described from the Velasco Fm. (Zone P4) and is characteristic of Zones P4 and P5. We include crosswicksensis in the concept of the taxon occlusa; it bears a similar relationship to that observed in the Acarinina coalingensis! triplex (earlier rounded periphery)-/?ri »izriva (later angular periphery) morphotypic series. [Olsson et al. 1999]

Distinguishing features: Like M. acutispira but without raised early part of test.

Description

Biogeography and Palaeobiology

Geographic distribution: This species is widespread in the low to middle latitudes. [Olsson et al. 1999]
Aze et al. 2011 summary: Low to middle latitudes; based on Olsson et al. (1999)

Isotope paleobiology: Morozovella occlusa has ∂13C and ∂18O similar to coexisting M. velascoensis and Acarinina mckannai and more positive ∂13C and more negative ∂18O than Subbotina spp. (Shackleton et al., 1985; Lu and Keller, 1996). [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): Shackleton et al. (1985); Lu & Keller (1996)

Phylogenetic relations: This species probably evolved from M. pasionenesis by a decrease in umbilical size, development of a biconvex test, and reduction of the muricate, sharp adumbilical ridges to lightly muricate, gently rounded surfaces around the umbilicus. Morozovella occlusa is a sister species to M. acutispira, with which it shares the biconvex test shape and relatively constricted umbilicus. [Olsson et al. 1999]

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

Biostratigraphic distribution

Geological Range:
Notes: Top of Zone P3b (typical crosswicksensis); Zone P4-P5 (typical occlusa). [Olsson et al. 1999]
Last occurrence (top): at top of E2 zone (100% up, 55.2Ma, in Ypresian stage). Data source: Olsson et al. (1999) f5a
First occurrence (base): near top of P3b subzone (90% up, 60.8Ma, in Selandian stage). Data source: Olsson et al. (1999) f5a

Primary source for this page: Olsson et al. 1999 - Atlas of Paleocene Planktonic Foraminifera, p. 62

References:

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

Gohrbandt, K. (1963). Zur Gliederung des Palaeogen im Helvetikum nordlich Salzburg nach planktonischen Foraminiferen. Mitteilungen der Geologischen Gesellschaft in Wien. 56(1): 63-. gs

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

Loeblich, A. R. & Tappan, H. (1957b). Planktonic foraminifera of Paleocene and early Eocene Age from the Gulf and Atlantic coastal plains. In, Loeblich, A. R. , Jr., Tappan, H., Beckmann, J. P., Bolli, H. M., Montanaro Gallitelli, E. & Troelsen, J. C. (eds) Studies in Foraminifera. U.S. National Museum Bulletin. 215: 173-198. gs V O

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 V O

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

Samanta, B. K. (1970). Middle Eocene Planktonic Foraminifera from Lakhpat, Cutch, Western India. Micropaleontology. 16(2): 185-215. gs

test outline:	Lobate	chamber arrangement:	Trochospiral	edge view:	Equally biconvex	aperture:	Umbilical-extraumbilical
sp chamber shape:	Crescentic	coiling axis:	Moderate	periphery:	Muricocarinate	aperture border:	Thin lip
umb chbr shape:	Subtriangular	umbilicus:	Narrow	periph margin shape:	Subangular	accessory apertures:	None
spiral sutures:	Raised muricate	umb depth:	Deep	wall texture:	Smooth	shell porosity:	Finely Perforate: 1-2.5µm
umbilical or test sutures:	Moderately depressed	final-whorl chambers:	4.0-5.0	N.B. These characters are used for advanced search. N/A - not applicable

Morozovella occlusa

Taxonomy

Description

Biogeography and Palaeobiology

Biostratigraphic distribution

References:

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