Back
Bosea granorugosa
Bosea granorugosa, He Chengquan and Qian Zeshu, 1979
Holotype: He Chengquan and Qian Zeshu, 1979, pl.1, fig.2
Age: Late Eocene-Oligocene
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [He Chengquan and Qian Zeshu, 1979]: (Translation: GSC, courtesy R. Fensome)
Description:
The tract has a subcircular ambital outline. It is provided with a large "pylome", which, however, may represent the epitractal archaeopyle; the operculum is attached.
No apical or antapical horns are observed, nor a cingulum or tabulation.
The hypotract is larger than the epitract. The wall of the tract is thin and bears folds. The surface is densely covered with rugose ornamentation accompanied by a small number of coarsely granular sculpturing elements; the rugulae curve in a vermicular pattern and vary in thickness; some of the rugulae seem to be composed of interconnected granules and have a tubercular sort of appearance; the rugulae also vary in length, with relatively long ones (3-4 µm) being in the majority and the shorter ones (about 2 µm) being in the minority; some of the rugulae have edges that extend beyond the outer contour line to appear like short spines (approximately 0.8 µm in height). The outer contour line is a trifle undulating to finely serrated. A yellow-coloured nucleus-like structure may be present.
Dimensions:
The holotype has a diameter of 50 µm. The range of variation is 40-50 µm (three specimens examined).
Affinities:
This species is distinguished from Bosea operculata (Jiabo, 1978) by the shortness and crowding of its rugose sculpture and by the additional presence of small numbers of coarse granules. In the latter species, the edges of the folds are low and do not prominently extend beyond the outer contour line.
Holotype: He Chengquan and Qian Zeshu, 1979, pl.1, fig.2
Age: Late Eocene-Oligocene
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [He Chengquan and Qian Zeshu, 1979]: (Translation: GSC, courtesy R. Fensome)
Description:
The tract has a subcircular ambital outline. It is provided with a large "pylome", which, however, may represent the epitractal archaeopyle; the operculum is attached.
No apical or antapical horns are observed, nor a cingulum or tabulation.
The hypotract is larger than the epitract. The wall of the tract is thin and bears folds. The surface is densely covered with rugose ornamentation accompanied by a small number of coarsely granular sculpturing elements; the rugulae curve in a vermicular pattern and vary in thickness; some of the rugulae seem to be composed of interconnected granules and have a tubercular sort of appearance; the rugulae also vary in length, with relatively long ones (3-4 µm) being in the majority and the shorter ones (about 2 µm) being in the minority; some of the rugulae have edges that extend beyond the outer contour line to appear like short spines (approximately 0.8 µm in height). The outer contour line is a trifle undulating to finely serrated. A yellow-coloured nucleus-like structure may be present.
Dimensions:
The holotype has a diameter of 50 µm. The range of variation is 40-50 µm (three specimens examined).
Affinities:
This species is distinguished from Bosea operculata (Jiabo, 1978) by the shortness and crowding of its rugose sculpture and by the additional presence of small numbers of coarse granules. In the latter species, the edges of the folds are low and do not prominently extend beyond the outer contour line.