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Current identification/main database link: Hedbergella tunisiensis (Boudagher-Fadel, 1995)
Diagnosis: This subspecies differs from B. speetonensis speetonensis in having a more involute spiral side with more curved intercameral sutures on the spiral side and an apertural porticus extending right over the periphery and reaching the last three chambers of the last whorl on the spiral side.
Description: Test about 0.28mm in diameter, a low trochospire with five to six chambers in the last whorl. The spiral side is almost completely involute and concave. Last three chambers show a beginning of asymmetry, highest in their posterior part. The sutures are depressed, curved on the spiral side and virtually radial on the umbilical side. The aperture is a low arch, has a porticus throughout its length, broadest posteriorly. The surface of the test is smooth, microperforate except for the umbilical shoulders, which may be imperforate.
Size: Test about 0.28mm in diameter
Extra details from original publication
Remarks: This subspecies is morphologically advanced beyond that shown by the type material of speetonensis in that the intra-extra umbilical aperture extends over the periphery of the last chamber of the previous whorl, with the portici encroaching onto the spiral side. This is apparent even up to the last 3 chambers of the final whorl. In such a case, the portici of the 2 or 3 chambers remain visible on the spiral side. The wholly septal aperture links chamber to chamber and is closed to the exterior on the spiral side (except in the last chamber of all). B. speetonensis tunisiensis derives (in the Early Albian) from the Late Aptian species speetonensis in becoming more involute, concave dorsally and in developing its later portici on the spiral side. The gradual evolution from the microperforate, evolute spiral side in B. speetonensis to the more involute spiral side in B. speetonensis tunisiensis leads to the multichambered involute but macroperforate forms of the Albian such as Alanlordella (Pl.2, figs 10-11).
Range: Early Albian.
BouDagher-Fadel, M. K. (1995). The planktonic Foraminifera of the Early Cretaceous of Tunisia compared to those of western and central Tethys. Paleopelagos. 5: 137-159. gs BouDagher-Fadel, M., Banner, F. T., Bown, P. R., Simmons, M. D. & Gorbachik, T. N. (1995). Gorbachikella from the Hauterivian, Barremian-Aptian of Tunisia. Revue de Micropaléontologie. 38(3): 179-193. gs
BouDagher-Fadel, M. K. (1995). The planktonic Foraminifera of the Early Cretaceous of Tunisia compared to those of western and central Tethys. Paleopelagos. 5: 137-159. gs
BouDagher-Fadel, M., Banner, F. T., Bown, P. R., Simmons, M. D. & Gorbachik, T. N. (1995). Gorbachikella from the Hauterivian, Barremian-Aptian of Tunisia. Revue de Micropaléontologie. 38(3): 179-193. gs
Blefuscuiana speetonensis tunisiensis compiled by the pforams@mikrotax project team viewed: 10-12-2019
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