Distinguishing features: Small to medium sized retecapsids with axial cross bars that are broad and bright in XPL with median extinction lines. Distinctly bicyclic rim image in XPL.
Taxonomy:
Farinacci & Howe catalog pages: Retecapsa incompta *
Distinguishing features: Small to medium sized retecapsids with axial cross bars that are broad and bright in XPL with median extinction lines. Distinctly bicyclic rim image in XPL.
Morphology remarks: The earliest occurring cretarhabdid coccolith.
Geological Range:
Last occurrence (top): within Middle Oxfordian Substage (159.70-160.84Ma, top in Oxfordian stage). Data source: Bown & Cooper 1998
First occurrence (base): at base of NJ8a subzone (0% up, 174.6Ma, in Toarcian stage). Data source: Bown & Cooper 1998 (fig 4) - zonal event; Mattioli & Erba 1999, fig. 12 - zonal marker
Plot of occurrence data:
Bown, P. R. & Cooper, M. K. E. (1989b). New calcareous nannofssils from the Jurassic. Journal of Micropalaeontology. 8: 91-96. gs 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 Bown, P. R. (1987a). Taxonomy, evolution, and biostratigraphy of Late Triassic-Early Jurassic calcareous nannofossils. Special Papers in Palaeontology. 38: 118-. gs Bown, P. R., Cooper, M. K. E. & Lord, A. R. (1988). A calcareous nannofossil biozonation scheme for the early to mid Mesozoic. Newsletters on Stratigraphy. 20: 91-114. 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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Retecapsa incompta compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 8-12-2019
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