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Basic analyses of this taxon were made by Luterbacher (1964) and Blow (1979). The latter observed that the "holotype" individual of Pseudogloborotalia pasionensis Bermudez at the National Museum of Natural History is coiled in a direction (sinistral) opposite to that of the photograph (dextral) of the "holotype" (Bermudez, 1961, pl. 16: fig. 8a,b); however, it is the specimen (identified as Pseudogloborotalia velascoensis (Cushman)) illustrated on pl. 16: fig. lla,b (and not that illustrated as fig. 8a,b), which is the holotype of pasionensis and which was examined by Blow and ourselves in the Cushman Collection (USNM 639063). The holotype of P. pasionensis shows characters similar to P. velascoensis, which indicate its close relationship with that taxon, but it has a low conical test as opposed to the high conical test typical of P. velascoensis. Luterbacher (1964) provided a revised and amplified description of this species based on topotypes supplied by Bermudez. The analyses of Blow and Luterbacher are essentially compatible, with the exception that Luterbacher (1964) recorded 5-7 chambers as typical of this form, whereas Blow (1979) noted 9-10 (and occasionally up to 12) chambers
in the final whorl. [Olsson et al. 1999]
Catalog entries: Pseudogloborotalia pasionensis
Type images:
holotype: P. pasionensis
holotype: P. pasionensisDistinguishing 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: Like M. velascoensis but with reduced spire height, a decrease in the ornament around the umbilicus, and an increase in the number of chambers (usually 5-7, up to 10).
Character matrix
| test outline: | Lobate | chamber arrangement: | Trochospiral | edge view: | Planoconvex | aperture: | Umbilical-extraumbilical |
| sp chamber shape: | Petaloid | coiling axis: | Moderate | periphery: | Muricocarinate | aperture border: | N/A |
| umb chbr shape: | Subtriangular | umbilicus: | Wide | periph margin shape: | Subangular | accessory apertures: | None |
| spiral sutures: | Raised muricate | umb depth: | Deep | wall texture: | Moderately muricate | shell porosity: | Finely Perforate: 1-2.5µm |
| umbilical or test sutures: | Moderately depressed | final-whorl chambers: | 6.5-7.5 | N.B. These characters are used for advanced search. N/A - not applicable | |||
Geographic distribution
Aze et al. 2011 summary: Low latitudes; based on Olsson et al. (1999)
Isotope paleobiology
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): Shackleton et al. (1985); Lu & Keller (1996)
Phylogenetic relations
Most likely ancestor: Morozovella velascoensis - at confidence level 4 (out of 5). Data source: Olsson et al. (1999) f5a.
Likely descendants: Morozovella acutispira; Morozovella occlusa;
plot with descendants
Geological Range:
Notes: Zone P3b to Zone P5. Luterbacher (1964) considered "pasionensis" restricted to the Globorotalia aequa Zone (= Zone P6a this paper), whereas Blow (1979) considered it restricted to (his) Zone P5 (i.e., prior to the appearance of M. subbotinae) with questionable or sporadic occurrences in (his) Zones P4 and P6. In our studies, we have found that M. pasionensis appears slightly higher or later than the initial appearance ofM. velascoensis in Zone P3b, and that it ranges throughout Zones P4 and P5. We have not observed it ranging into post-M velascoensis (Zone P5) levels. It was ancestral to M. acutispira and M. occlusa, which appear in the terminal part of Zone P3b. [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): in upper part of P3b subzone (70% up, 60.9Ma, in Selandian 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. 63
Bermudez, P. J. (1961). Contribucion al estudio de las Globigerinidea de la region Caribe-Antillana (Paleoceno-Reciente). Editorial Sucre, Caracas. (3): 1119-1393. 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 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 Olsson, R. K., Hemleben, C., Berggren, W. A. & Huber, B. T. (1999). Atlas of Paleocene Planktonic Foraminifera. Smithsonian Institution Press, Washington, DC. (85): 1-252. gsReferences:
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Morozovella pasionensis compiled by the pforams@mikrotax project team viewed: 10-12-2024
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