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Fibradinium annetorpense

Fibradinium annetorpense Morgenroth, 1968

Originally (and now) Fibradinium, subsequently Phanerodinium.
Below, 1987, transferred this species to Phanerodinium Deflandre, 1937. Lentin and Williams, 1989, retained it in Fibradinium.

Holotype: Morgenroth 1968, Plate 42, fig. 4
Locus typicus: Anetorp. Denmark
Stratum typicum: Saltholm limestone (Danian).
Age: Danian

Original description (complementary to the diagnosis of genus): Morgenroth 1968, p. 4
The double-layer theca wall consists of an inner thin membrane and a thick outer layer of fibrous structure on which the outlines of the plates are more or less clearly defined by slightly raised ridges. The apex is characterized by ?7 apical plates of which 1' lies on the extension of the longitudinal groove. A pentagonal "apical area" to which 6 pre-equatorial plates are adjacent, appears to be subdivided into 6 small plates; five of these surround one centrally located plate (see Fig . 2 ). However, the outlines of the plates on the apical are indistinct and cannot be determined in all specimens. In the formation of the archaeopyle, these ?6 apical plates are cast off so that a pentagonal opening is created. The transverse groove is circular in most specimens; in some, however, it spirals slightly in a counterclockwise direction. Six post-equatorial plates, one intercalary plate and one antapical plate are located on the hypotheca. The narrow longitudinal groove widens in the shape of a drop on the hypotheca.

Dimensions:
Length of theca: 32µ (28µ/3µ)
Width of theca: 28µ (22µ/31µ)
Thickness of theca wall: 3230 (2µ/5m) (25 measurements)
Number of specimens examined: 27

Supplemental description: Hultberg, 1985, p.122
Proximate cyst, composed of endophragm and periphragm, closely appressed. The surface of the periphragm is strongly granulate. The shape of the cyst is ellipsoidal.
Paratabulation is expressed by fibrous parasutural ridges, formed by the periphragm. Paraplates 1'' to 6'', 1''' to 6''', 1p, and 1'''', are clearly distinguishable. The apical paratabulation is not clearly discernible, but presumably follows the standard microdinioid paratabulation, which contains seven apical paraplates. Paracingulum and parasulcus are clearly indicated by parasutural ridges.
Size 27-32 Ám (length), 20-32 Ám (breadth).

G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Fibradinium annetorpense Morgenroth, 1968. The archeopyle is apical. Size: length 28-34 µm, width 22-31 µm, wall thickness 2-5 µm.
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