Daughter taxa (time control age-window is: 0-800Ma)![]() | Granddaughter taxa | ||||
![]() | Futyania Very small circular to elliptical placoliths with narrow central area and tube-elements extended distally to form an elevated flower-like distal structure. | ||||
Hornibrookina Elliptical placoliths with bicyclic distal shields with raised tube cycle and central area grill formed from robust bars. | |||||
![]() | ![]() | ![]() | Neobiscutum Very small to small placoliths with closed or narrow central areas. Shields are dark in XPL with bright tube cycle. | ||
![]() | Prinsius Prinsiacean placoliths with narrow central areas that are closed or have a narrow opening that may be spanned by a narrow plate/net. Typically very small to medium sized. | ||||
![]() | Toweius Elliptical to circular prinsiacean placoliths with central areas that are typically spanned by a proximal net and/or distal conjunct nets or bars. Typically medium sized. | T. serotinus T. pertusus T. tovae T. eminens T. occultatus T. reticulum T. selandianus T. rotundus T. patellus T. callosus T. magnicrassus T. gammation T. sp. |
Taxonomy:
Distinguishing features: Placoliths with R-units forming the lower layer of proximal shield, inner tube and middle tube; V-units forming an upper layer to the proximal shield, outermost tube and the distal shield. In LM they display a dark outer cycle and brighter inner cycle. Central-area structures are conjunct, formed from the R-units.
Farinacci & Howe catalog pages: Prinsiaceae [no catalog entry yet]
Morphology: Typically small to medium sized placoliths with R-units forming the proximal shield-element and two tube-elements, and V-units forming an upper layer to the proximal shield, an outermost tube and the distal shield. In LM they display a dark outer cycle and brighter inner cycle. Central-area structures are conjunct, being formed from either the central-area elements or the inner tube-elements of the proximal shield.
Phylogenetic relations: Toweius gave rise to Reticulofenestra by loss of the V-units - the middle tube cycle of Prinsiaceae forms the outer tube of reticulofenestrids and extends to form the distal shield - see Gallagher (1989) and Young (1989). The similariy of the structures are much clearer in proximal view than distal view.
Tags | LITHS: |
Metrics | Lith size: 1->16µm; |
Geological Range:
Last occurrence (top): in upper part of Lutetian Stage (74% up, 42.9Ma, in Lutetian stage). Data source: Total of range of species in this database
First occurrence (base): at base of Danian Stage (0% up, 66Ma, in Danian stage). Data source: Total of range of species in this database
Plot of occurrence data:
Gallagher, L. T. (1989). Reticulofenestra : A critical review of taxonomy, structure and evolution. In, Crux, J. A. & van Heck, S. E. (eds) Nannofossils and their applications: Proceedings of the 2nd INA Conference, London 1987. British Micropalaeontological Society Publication Series. 41-75. gs Hay, W. W. & Mohler, H. P. (1967). Calcareous nannoplankton from Early Tertiary rocks at Point Labau, France and Paleocene-Early Eocene correlations. Journal of Paleontology. 41(6): 1505-1541. gs Perch-Nielsen, K. (1985a). Cenozoic calcareous nannofossils. In, Bolli, H. M., Saunders, J. B. & Perch-Nielsen, K. (eds) Plankton Stratigraphy. Cambridge University Press, Cambridge 427-555. gs Young, J. R. & Bown, P. R. (1997a). Cenozoic calcareous nannoplankton classification. Journal of Nannoplankton Research. 19(1): 36-47. gs V O Young, J. R. (1989). Observations on heterococcolith rim structure and its relationship to developmental processes. In, Crux, J. A. & van Heck, S. E. (eds) Nannofossils and their applications: Proceedings of the 2nd INA Conference, London 1987. British Micropalaeontological Society Publication Series. 1-20. gs V OReferences:
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Prinsiaceae compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 7-3-2021
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