Watznaueria bayackii
Set number: 3197
-
1
-
2
-
3
-
4
-
5
-
6
-
7
-
8
-
9
-
10
10µm
Set number: 3199
-
1
-
2
-
3
-
4
-
5
-
6
-
7
-
8
-
9
-
10
-
11
-
12
-
13
-
14
-
15
-
16
10µm
Set number: 3200
-
1
-
2
-
3
-
4
-
5
-
6
-
7
-
8
-
9
-
10
-
11
-
12
-
13
-
14
-
15
-
16
-
17
-
18
-
19
-
20
10µm
Set number: 3201
-
1
-
2
-
3
-
4
-
5
-
6
-
7
-
8
-
9
-
10
-
11
-
12
-
13
-
14
-
15
-
16
10µm
Watznaueria bayackii Worsley, 1971
In plan view under cross-polarised light, the shields display white interference colours that decrease in intensity towards the periphery, where only the distal shield is present, and show inclined extinction lines and length-fast (–) elongation. The central area is not resolvable under cross-polarised light. Extinction angles show considerable variation, typically ranging from about 65° to 75°.
Medium-sized (3.0–7.0 µm), elliptical species of Watznaueria, characterised by a distal shield that is larger than the proximal shield and a narrow central area bearing two small depressions positioned at opposite ends along the long axis, connected by a suture. The central area and its features are resolvable only under phase-contrast illumination.
Watznaueria bayackii differs from Watznaueria supracretacea in its optical properties: Watznaueria bayackii exhibits inclined extinction with extinction angles of about 65–75°, whereas Watznaueria supracretacea displays parallel extinction (0°).
Watznaueria bayackii is further distinguished from Watznaueria diaphanae by the nature of the central area. In W. bayackii, the central area is not resolvable under cross-polarised light, whereas in W. diaphanae the narrow, elongate central area is visible and exhibits dimmer interference colours than the shields.
Holotype
Watznaueria bayackii
Worsley, 1971
Hauterivian
DSDP Leg 1, Site 4, Blake Bahama Basin, West Atlantic