Taxonomy
Original description: Test free, trochoid; chambers globular (11-12 in the dorsal spire), not closely appressed, often the last chamber appearing to be almost detached in the adult stage; wall hyaline, finely perforate and cancellate; aperture small and indistinct, opening into the umbilicus.
Entries in the Catalog of original descriptions: Globigerina portsdownensis
Character matrix
| test outline: | Circular | chamber arrangement: | Trochospiral | edge view: | Spiroconvex | aperture: | Umbilical-extraumbilical |
| sp chamber shape: | Globular | coiling axis: | Moderate | periphery: | N/A | aperture border: | N/A |
| umb chbr shape: | Globular | umbilicus: | Narrow | periph margin shape: | Broadly rounded | accessory apertures: | None |
| spiral sutures: | Strongly depressed | umb depth: | Shallow | wall texture: | Coarsely muricate | shell porosity: | Finely Perforate: 1-2.5µm |
| umbilical or test sutures: | Strongly depressed | final-whorl chambers: | 5-6 | N.B. These characters are used for advanced search. N/A - not applicable | |||
Geological Range:
Last occurrence (top): within Cenomanian Stage (93.90-100.50Ma, top in Cenomanian stage). Data source: [copied from Chronos database]
First occurrence (base): within Cenomanian Stage (93.90-100.50Ma, base in Cenomanian stage). Data source: [copied from Chronos database]
Plot of range and occurrence data:
Eicher, D. L. & Worstell, P. (1970). Lunatriella, a Cretaceous heterohelicid foraminifer from the western interior of the United States. Micropaleontology. 16(1): 117-121. gs Leckie, M. (1984). Mid-Cretaceous planktonic foraminiferal biostratigraphy off Central Morocco, Deep Sea Drilling Project Leg 79, Sites 545 and 547. Initial Reports of the Deep Sea Drilling Project. 79: 579-620. gs Williams-Mitchell, E. (1948). The zonal value of foraminifera in the Chalk of England. Proceedings of the Geologists' Association. 59: 96-. gsReferences:

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Muricohedbergella portsdownensis compiled by the pforams@mikrotax project team viewed: 11-8-2026
Short stable page link: https://mikrotax.org/pforams/index.php?id=110373 Go to Archive.is to create a permanent copy of this page - citation notes |
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