holotype: Hedbergella bornholmensis
holotype: Hedbergella bornholmensis
Taxonomy
holotype: Hedbergella bornholmensis
holotype: Hedbergella bornholmensisOriginal description: "Test free, low trochospiral, equatorial periphery strongly lobulate, axial periphery rounded. Chambers subglobular to subspherical, three and one half to four chambers in the final whorl; initial chambers increasing gradually insize, final three or four increasing very rapidly, last formed chamber much larger than penultimate, giving test a trilobate appearance. Spiral and umbilical sutures radial to slightly curved, depressed, distinct. Wall calcareous, perforate, surface covered with small spines. Umbilical deep and narrow in juvenile stage, becoming shallower in adult. Primary aperture is a high interiomarginal-umbilical arch a narrow bordering lip. "Comment. - The species is similar to Whiteinella baltica, Douglas and Rankin, but may be differentiated by, (1) the trilobate shape of the test, (2) the rapid whorl expansion in the final volution, and (3) the more extra-umbilical position of the primary aperture. Hedbergella portsdownensis (Williams-Mitchell) [Globigerina portsdownensis, 1948] is more strongly spiroconvex, has a smaller and deeper umbilicus and lacks the distinctive spinose surface. Apart from Bornholm Island, the species has been found in northern Germany and its presence is suspected in other parts of the Polish-Danish seaway."
Entries in the Catalog of original descriptions: Hedbergella bornholmensis
Geological Range:
Last occurrence (top): in lower part of Santonian Stage (30% up, 85.5Ma, in Santonian stage). Data source:
First occurrence (base): at base of Santonian Stage (0% up, 86.3Ma, in Santonian stage). Data source:
Plot of occurrence data:
Dec 2017 - Plotting of Neptune data has been re-enabled on the Mesozoic pages following revision of the age-models in Neptune. The data is, however, still very sparse for the Early Cretaceous
Character matrix
| test outline: | Triangular | chamber arrangement: | Trochospiral | edge view: | Equally biconvex | aperture: | Umbilical-extraumbilical |
| sp chamber shape: | Inflated | coiling axis: | Very low | periphery: | N/A | aperture border: | Thin lip |
| umb chbr shape: | Inflated | umbilicus: | Narrow | periph margin shape: | Broadly rounded | accessory apertures: | None |
| spiral sutures: | Strongly depressed | umb depth: | Shallow | wall texture: | Moderately muricate | shell porosity: | |
| umbilical or test sutures: | Strongly depressed | final-whorl chambers: | 3.5-4.0 | N.B. These characters are used for advanced search. N/A - not applicable | |||
Douglas, R. G. & Rankin, C. (1969). Cretaceous planktonic foraminifera from Bornholm and their zoogeographic significance. Lethaia. 2: 185-217. gsReferences:
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Whiteinella bornholmensis compiled by the pforams@mikrotax project team viewed: 16-12-2019
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