Bolli (1957a) and Blow (1979) considered that S. velascoensis evolved from S. triangularis at, or near, the Zone P3/P4 boundary and believed that 5. velascoensis represented a dead-end lineage. Subbotina velascoensis has a much different wall texture than does S. triangularis. The latter species has a finer asymmetrical cancellate wall with coalescing spine collars, whereas S. velascoensis has a symmetrical, coarsely cancellate wall texture. In 5. velascoensis, the spines are set at the intersection of the cancellate ridges and are not supported by spine collars (Plate 29: Figure 11) as in S. triangularis (Plate 26: Figures 12, 13). We consider S. velascoensis as the end member of the symmetrical coarsely cancellate lineage that begins with 5. cancellata. Subbotina cancellata, gives rise to S. velascoensis at, or near, the Zone P3/P4 boundary. We agree with Bolli and Blow that S. velascoensis represents a dead-end lineage. Globigerina quadritriloculinoides Khalilov (1956) from the upper Paleocene of Azerbaizhan exhibits the characteristic quadrate-shaped morphology of S. velascoensis. The holotype figures show a coarsely cancellate wall, also typical of S. velascoensis. [Olsson et al. 1999]
Catalog entries: Globigerina velascoensis, Globorotalia tortiva, Globigerina velascoensis compressa, Globigerina quadritriloculinoides, Globigerina triloculinoides nanus
Type images:Distinguishing features:
Parent taxon (Subbotina): Low trochospiral, tripartite test, with 3-4 rapidly inflating, globular chambers in final whorl.
Umbilicus nearly closed by tight coiling.
Wall cancellate with spines at nodes of the ridges, +/- spine collars.
This taxon: Test tightly coiled, subquadrate, test with compressed chambers. Final chamber much compressed, elongate, forms about half of the test and typically overhangs the earlier chambers. Aperture umbilical; thin elongate lip along part of aperture with squared-of ends. The test wall is coarsely and symmetrically cancellate, spinose.
Character matrix
test outline: | Quadrate | chamber arrangement: | Trochospiral | edge view: | Equally biconvex | aperture: | Umbilical |
sp chamber shape: | Inflated | coiling axis: | Low | periphery: | N/A | aperture border: | Thin lip |
umb chbr shape: | Inflated | umbilicus: | Narrow | periph margin shape: | Broadly rounded | accessory apertures: | None |
spiral sutures: | Strongly depressed | umb depth: | Deep | wall texture: | Finely pustulose | shell porosity: | Finely Perforate: 1-2.5µm |
umbilical or test sutures: | Strongly depressed | final-whorl chambers: | 3-4 | N.B. These characters are used for advanced search. N/A - not applicable |
Geographic distribution
Aze et al. 2011 summary: Cosmopolitan; based on Olsson et al. (1999)
Isotope paleobiology
Aze et al. 2011 ecogroup 3 - Open ocean thermocline. Based on light _13C and relatively heavy _18O. Sources cited by Aze et al. 2011 (appendix S3): Berggren & Norris (1997); Coxall et al. (2000)
Phylogenetic relations
Most likely ancestor: Subbotina triloculinoides - at confidence level 3 (out of 5). Data source: Olsson et al. 1999 f5a (but Olsson et al 2005 f6.2 show it evolving from cancellata).
Likely descendants: Subbotina hornibrooki;
plot with descendants
Geological Range:
Notes: Zone P3b to Zone P6a. [Olsson et al. 1999]
Last occurrence (top): within E3 zone (54.61-55.20Ma, top in Ypresian stage). Data source: Olsson et al. 1999
First occurrence (base): within P3b subzone (60.73-61.33Ma, base in Selandian stage). Data source: Olsson et al. 1999
Plot of occurrence data:
Primary source for this page: Olsson et al. 1999 - Atlas of Paleocene Planktonic Foraminifera, p. 33
Bolli, H. M. & Cita, M. B. (1960). Globigerine e Globorotalie del Paleocene di Paderno d'Adda (Italia). Rivista Italiana di Paleontologia e Stratigrafia. LXVI(3): 1-42. gs Bolli, H. M. (1957d). The genera Globigerina and Globorotalia in the Paleocene-Lower Eocene Lizard Springs Formation of Trinidad. 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: 61-82. gs Cushman, J. A. (1925e). Some new foraminifera from the Velasco shale of Mexico. Contributions from the Cushman Laboratory for Foraminiferal Research. 1(1): 18-23. 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. 108: 1-182. gs Khalilov, D. M. (1956). 0 pelagicheskoy faune foraminifer Paleogenovykh otlozheniy Azerbaydzhana [Pelagic Foraminifera of the Paleogene Deposits of the Azerbaizhan SSR]. Trudy Instituta Geologii, Akademiya Nauk Azerbaidzhanskoi SSR. 17: 234-255. gs 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. gs Shutskaya, E. K. (1970a). Morphologic groups and descriptions of species of Globigerina and Acarinina in the lower Paleogene of the Crimea, the Caucasus Foreland, and western Central Asia. Trudy Vsesoyuznego Neftyanogo Nauchno-Issledovatel'skogo Geologo-Razvedochnogo Instituta (VNIGRI). 69: 79-113. gs White, M. P. (1928). Some Index Foraminifera of the Tampico Embayment Area of Mexico. Journal of Paleontology. 2(3): 177-215. gs References:
Subbotina velascoensis compiled by the pforams@mikrotax project team viewed: 14-12-2024
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