Low trochospiral, lobulate, later chambers club-shaped
Specimens which cannot be assigned to established species
| Daughter taxa (time control age-window is: 0-800Ma) | ||||
| | | Clavatorella bermudezi Low trochospiral, lobulate, later chambers club-shaped | |
| Clavatorella sp. Specimens which cannot be assigned to established species | ||||
Clavatorella has a low trochospiral test, which is evolute on the spiral side throughout. The chambers are subspherical or ovate in early stages, later becoming radially elongate and club shaped. This genus is distinguished from Globorotaloides by the presence of radially elongate and club-shaped· chambers in the later ontogenic development. Clavatorella differs from Protentella by its distinctly and strongly trochospiral test and umbilical-extraumbilical aperture.
Blow (1965) believed Clavatorella evolved from a globorotaliid ancestor and later (Blow, 1969) treated Clavatorella as a subgenus of Globorotalia. Lipps (1966) observed that the surface ultrastructure of Clavatorella bermudezi, the type species of Clavatorella, is similar to Protentella, and therefore placed Clavatorella in synonymy with Protentella. For the same reason, Srinivasan and Kennett (1975) treated Clavatorella as a subgenus of Protentella. Although the surface ultrastructures of Clavatorella (C. bermudezi) and Protentella (P. prolixa) are the same, we now believe that the difference in the degree of trochospiral coiling in later stages between these two genera justifies separation of Clavatorella from Protentella. The similarities in surface ultrastructure between Clavatorella and Protentella suggests a phylogenetic relationship between the two (Text Fig. 24) [Kennett & Srinvasan 1983]
Catalog entries: Clavatorella
Distinguishing features:
Parent taxon (Globigerinidae): Wall spinose, usually with 3½-6 globular chambers in final whorl, trochospiral or planispiral
This taxon: low trochospiral test, later chanbers radially elongate and club shaped.
The genus Clavatorella developed from Globorotaloides hexagona in the Early Miocene and is ancestral to Protentella (Text Fig. 24). [Kennett & Srinivasan 1983]
Phylogenetic relations
Most likely ancestor: Globorotaloides - at confidence level 2 (out of 5). Data source: Kennett & Srinivasan 1983; .
Geological Range:
Last occurrence (top): at top of M7 zone (100% up, 13.8Ma, in Serravallian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within M5b subzone (15.10-16.27Ma, base in Burdigalian stage). Data source: Total of ranges of species in this database
Plot of occurrence data:
Primary source for this page: Kennett & Srinivasan 1983, p.218
Blow, W. H. (1965). Clavatorella, a new genus of the Globorotaliidae. Micropaleontology. 11(3): 365-368. gs Blow, W. H. (1969). Late middle Eocene to Recent planktonic foraminiferal biostratigraphy. In, Bronnimann, P. & Renz, H. H. (eds) Proceedings of the First International Conference on Planktonic Microfossils, Geneva, 1967. E J Brill, Leiden 380-381. gs Kennett, J. P. & Srinivasan, M. S. (1983). Neogene Planktonic Foraminifera. Hutchinson Ross Publishing Co., Stroudsburg, Pennsylvania. 1-265. gs Lipps, J. H. (1966). Wall structure, systematics and phylogeny of Cenozoic planktonic foraminifera. Journal of Paleontology. 40(6): 1257-1274. gs Srinivasan, M. S. & Kennett, J. P. (1975c). The status of Bolliella, Beella, Protentella and related planktonic foraminifera based on surface ultrastructure. Journal of Foraminiferal Research. 5(3): 155-165. gsReferences:
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Clavatorella compiled by the pforams@mikrotax project team viewed: 11-10-2024
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