Watznaueria magnobliqua
Set number: 3244
-
1
-
2
-
3
-
4
-
5
-
6
-
7
-
8
-
9
-
10
-
11
-
12
-
13
-
14
-
15
-
16
-
17
-
18
-
19
-
20
10µm
Watznaueria magnobliqua Varol, in prep
Large species of Watznaueria (>8 μm) are characterised by an elliptical placolith in which the tube cycles are obliquely orientated relative to the long axis of the shield, with a rotation angle of approximately 31°. The distal shield is slightly larger than the proximal shield. A dim cycle separates the tube cycle from the shields.
From Latin magnus, meaning large, and obliquus, meaning oblique or slanting, referring to the large size of the coccolith and the oblique orientation of the central area relative to the long axis of the shield.
In plan view under cross-polarised light, the species is characterised by white interference colours, inclined extinction lines, and length-fast (–) elongation. On the distal side, the shields exhibit an extinction angle of approximately 73°. Owing to the oblique arrangement of the constituent elements, extinction angles within the tube cycles cannot be measured directly. Nevertheless, the apparent angle between the extinction directions of the tube-cycle elements is approximately 75°, indicating an element obliquity of about 15°.
The locking cycle remains in constant extinction, forming a subdued boundary between the tube cycles and the shields.