Furcatolithus bulbulus
Set number: 843
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10µm
Sphenolithus bulbulus Bergen & de Kaenel in Bergen et al., 2017
Furcatolithus bulbulus is an intermediate form between Furcatolithus ciperoensis (Bramlette & Wilcoxon, 1967) Howe, 2021 and Furcatolithus avis (Aljahdali et al., 2015) Howe, 2021. In all three species, the duolithic apical spine is a kite shape in the axial section with an acute proximal angle.
The differences between the above species are in the shape of the proximal cycle. It is a relatively high cylindrical shape in Furcatolithus ciperoensis but a hollow frustum shape in Furcatolithus bulbulus, whereas a semi-open umbrella shape in Furcatolithus avis. The peripheries of the proximal cycles are convex in Furcatolithus bulbulus.
Aljahdali, M., Wise, S. W., Bergen, J. A., Pospichal, J. J., 2015. A new biostratigraphically significant Late Oligocene Sphenolithus species from the equatorial region. Micropaleontology 61(3), 193-197.
Bergen, J. A., de Kaenel, E., Blair, S. A., Boesiger, T. M., Browning, E., 2017. Oligocene-Pliocene taxonomy and stratigraphy of the genus Sphenolithus in the circum North Atlantic Basin: Gulf of Mexico and ODP Leg 154. Journal of Nannoplankton Research 37(2-3), 77-112.
Bramlette, M. N., Wilcoxon, J. A., 1967. Middle Tertiary calcareous nannoplankton of the Cipero section, Trinidad, W.I. Tulane Studies in Geology and Paleontology 5, 93-131.
Howe, R., 2021. Ultrastructure and taxonomy of the family Sphenolithaceae. Journal of Nannoplankton Research 39(1), 29-75.
Holotype
Sphenolithus bulbolus
Bergen & de Kaenel in Bergen et al., 2017
Late Oligocene
ODP Leg 149, Site 900, Iberia Abyssal Plain, North Atlantic