Globorotalia archeomenardii Bolli 1957 from: Bolli, H.M. (1957): Planktonic foraminifera from the Oligocene-Miocene Cipero and Lengua formations of Trinidad, B.W.I.. In: Studies in Foraminifery, Bulletin of the U.S. National Museum Vol. 215 Eds: Loeblich, A.R.Tappan, H.Beckmann, J.P.Bolli, H.M.Gallitelli, E.M.Troelsen, J.C. p. 97-123 . |
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Species Globorotalia archeomenardii Bolli 1957 |
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Alternative name: |
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Diagnosis / Definition: |
Bolli (1957):
Shape of test low trochospiral, compressed; equatorial periphery slightly lobate; axial periphery acute with a thin but distinct keel. Wall calcareous, very finely perforate, surface smooth. Chambers angular rhomboid, strongly compressed; 12-15, arranged in about 3 whorls, the 4-5 chambers of the last whorl increase fairly rapidly in size. Sutures on spiral side strongly curved; on umbilical side radial to slightly curved, depressed. Umbilicus small, fairly shallow. Aperture a low slit; interiomarginal, umbilical extraumbilical. Coiling random. Largest diameter of holotype 0.3 mm. |
Discussion / Comments: |
Bolli & Saunders (1985):
This small species with a diameter of only about 0.3 mm possesses thin chamber walls and a delicate keel. Furthermore, compared with the considerably larger G. praemenardii, its spiral side appears more convex and the equatorial periphery less lobate.
Bolli (1957):
Globorotalia archeomenardii, new species, is distinguished from G. menardii (d'Orbigny) and G. praemenardii Cushman and Stainforth by having a more convex spiral side and in being less lobate. The range in size of the specimens of the new species is very small in contrast to that of the other two species. Typical G. archeomenardii disappear with the first appearance of G. praemenardii. It is probably the ancestor of the G. praemenardii menardii suite.
Chaisson & Leckie (1993):
Similar species: Globorotalia archeomenardii has a distinctly more biconvex
test and angular peripheral margin than its ancestor Globorotalia
praescitula (Kennett and Srinivasan, 1983), and it is more convex on the spiral
side than its descendant G. praemenardii. In addition, G. archeomenardii also
has more chambers than G. praescitula (five to five and a half, compared with
four to four and a half), and it lacks the raised dorsal sutures and well-developed
peripheral keel characteristic of G. praemenardii. |
Synonym list: |
Bolli & Saunders (1985):
Bolli (1957):
Vincent & Toumarkine (1990):
Chaisson & Leckie (1993):
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Was used in synonym list of: |
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References: |
Bolli,H.M. (1957): Planktonic foraminifera from the Oligocene-Miocene Cipero and Lengua formations of Trinidad, B.W.I.. In: Studies in Foraminifery, Bulletin of the U.S. National Museum Vol. 215 Eds: Loeblich, A.R.Tappan, H.Beckmann, J.P.Bolli, H.M.Gallitelli, E.M.Troelsen, J.C. p. 97-123
Kennett,J. and Srinivasan,M.S. (1983): Neogene Planktonic Foraminifera - A Phylogenetic Atlas.
Bolli,H.M. and Saunders,J.B. (1985): Oligocene to Holocene low latitude planktic foraminifers. In: Plankton Stratigraphy Eds: Bolli, H.M.Saunders, J.B. p. 155-262
Vincent,E. and Toumarkine,M. (1990): Neogene planktonic foraminifers from the Western Tropical Indian Ocean, Leg 115. In: Proceedings of the Ocean Drilling Program, Scientific Results Vol. 115 Eds: Duncan, R.A..Backman, J.Peterson, L.C. p. 795-836
Chaisson,W.P. and Leckie,R.M. (1993): High-Resolution Planktonic Foraminifer Biostratigraphy of Site 806, Ontong Java Plateau (Western Equatorial Pacific). In: Proceedings of the Ocean Drilling Program, Scientific Results Vol. 130 Eds: Berger, W.H.Kroenke, L.W..Mayer, L.A..et al. p. 137-178
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