Back
Tenua chinensis
From Fensome et al., 2019:
(He Chengquan, 1991, p.54–55, pl.9, figs.17–18) Fensome et al., 2019a, p.47.
Holotype: He Chengquan, 1991, pl.9, fig.17; Fensome et al., 2019a, fig.17S.
Originally Canningia, subsequently Circulodinium, thirdly (and now) Tenua Eisenack.
Age: Middle Eocene.
---------------------------------------------------------------------------------------------------
Original description: [He Chengquan, 1991]: (translated by Suning Hou, 07-01-2019):
Description:
Cyst is flat, outline nearly spherical to spherical-pentagons or nearly oval, length and width nearly equal, the widest in the equator. In the holotypes, the apical is convex, antapical slightly concave tail, the two wide-round antapical horns are significantly different in size.
Cingulum vaguely display or missing;
wall thickness about 1 μm, two layers, surface with dense granulate and sparse short spine like processes; the spines base wide, tip sharp, there are roughly 15-20 processes on the outline, not of uniform size, large ones length 5-6.5 μm, base width about 2 μm, small ones length about 2 μm, base width of 1μm; processes distribution nontabular.
Archeopyle apical, (tA) type, formed by the movement of the apical area, the edge is clearly angular, nicked/incision deep. Operculum completely separated, fell off or preserved in situ. With brownish core like thing.
Dimensions:
The total length of the holotype (including processes) 92 μm, width 92.5 μm, cyst length 87. 5 μm, width 87.5 μm, process length 2-5 μm ; another specimen total length (lack of top) 75 μm, width 82 μm, cyst length 72. 5 μm, width 77. 5 μm.
Affinities:
with Canningia aspera, the new species is distinguished from Canningia aspera by its obvious two antapical horns, surface with dense granulate and sparse short spine like processes, latter one generally lacks antapical horns and granulate, only with dense processes.
(He Chengquan, 1991, p.54–55, pl.9, figs.17–18) Fensome et al., 2019a, p.47.
Holotype: He Chengquan, 1991, pl.9, fig.17; Fensome et al., 2019a, fig.17S.
Originally Canningia, subsequently Circulodinium, thirdly (and now) Tenua Eisenack.
Age: Middle Eocene.
---------------------------------------------------------------------------------------------------
Original description: [He Chengquan, 1991]: (translated by Suning Hou, 07-01-2019):
Description:
Cyst is flat, outline nearly spherical to spherical-pentagons or nearly oval, length and width nearly equal, the widest in the equator. In the holotypes, the apical is convex, antapical slightly concave tail, the two wide-round antapical horns are significantly different in size.
Cingulum vaguely display or missing;
wall thickness about 1 μm, two layers, surface with dense granulate and sparse short spine like processes; the spines base wide, tip sharp, there are roughly 15-20 processes on the outline, not of uniform size, large ones length 5-6.5 μm, base width about 2 μm, small ones length about 2 μm, base width of 1μm; processes distribution nontabular.
Archeopyle apical, (tA) type, formed by the movement of the apical area, the edge is clearly angular, nicked/incision deep. Operculum completely separated, fell off or preserved in situ. With brownish core like thing.
Dimensions:
The total length of the holotype (including processes) 92 μm, width 92.5 μm, cyst length 87. 5 μm, width 87.5 μm, process length 2-5 μm ; another specimen total length (lack of top) 75 μm, width 82 μm, cyst length 72. 5 μm, width 77. 5 μm.
Affinities:
with Canningia aspera, the new species is distinguished from Canningia aspera by its obvious two antapical horns, surface with dense granulate and sparse short spine like processes, latter one generally lacks antapical horns and granulate, only with dense processes.