Distinguishing features: Small, broadly elliptical, biscutacean placolith with narrow central area spanned by a small axial cross.
Taxonomy:
Farinacci & Howe catalog pages: Similiscutum cruciulus *
Distinguishing features: Small, broadly elliptical, biscutacean placolith with narrow central area spanned by a small axial cross.
Geological Range:
Last occurrence (top): in lower part of NJT7a subzone (20% up, 180Ma, in Toarcian stage). Data source: Mattioli & Erba 1999
First occurrence (base): at base of NJ4a subzone (0% up, 190.2Ma, in Pliensbachian stage). Data source: Bown & Cooper 1998 (fig 4) - zonal event
Plot of occurrence data:
Bown, P. R. & Cooper, M. K. E. (1998). Jurassic. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 34-85. gs de Kaenel, E. & Bergen, J. A. (1993). New Early and Middle Jurassic coccolith taxa and biostratigraphy from the eastern proto-Atlantic (Morocco, Portugal and DSDP Site 547B). Eclogae Geologicae Helvetiae. 86(861-907): -. gs Mattioli, E. & Erba, E. (1999). Synthesis of calcareous nannofossil events in Tethyan lower and middle Jurassic successions. Rivista Italiana di Paleontologia e Stratigrafia. 105(3): 343-376. gsReferences:
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Similiscutum cruciulus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 12-12-2019
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