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Kleithriasphaeridium corrugatum

Kleithriasphaeridium corrugatum Davey, 1974

Holotype: Davey, 1974, pl.5, fig.1-2, text-fig.3
Locus typicus: Speeton, England
Stratum typicum: Early Barremian

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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.

Kleithriasphaeridium corrugatum Davey, 1974. According to Davey (1974, p.56-57), Kleithriasphaeridium corrugatum has strong, faintly ribbed tubular processes. The processes vary in length and width, with the sulcal processes being especially narrow. Distally, the processes expand slightly and terminate with a secate or denticulate margin. Proximally, the ribs become stronger and more numerous and extend onto the central body surface in a radial manner from the base of the processes. Usually midway between the processes the ribs tend to become vermiform. Occasionally two processes may be joined by a proximal membrane. The central body wall beneath each process is thick and coarsely tubular. Duxbury (1977) noted that K.corrugatum differs from K.fasciatum in having longer processes. Size: Central body diameter 35-52 µm, process length 23-36 µm.
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Original diagnosis: Davey, 1974, p. 56
The central body is almost spherical and bears strong, faintly ribbed tubular processes. The processes vary in length and particularly in width, with the sulcal processes being especially narrow. Distally the processes expand a little and terminate with a secate or denticulate margin. Proximally the ribs become stronger and more numerous; these extend onto the central body surface in a radial manner from the base of each process. Usually midway between two processes the ribs tend to become vermiform although ribs from adjacent processes are sometimes confluent. Rarely, two processes may be joined by a proximal membrane. The central body wall beneath each tubular processess is thick and coarsely granular. A precingular archaeopyle is always present.
Dimensions: central body length 35-52 Ám; process length: 23-36 Ám.

Original description: Davey, 1974, p.56-57
The cyst wall is approximately 1 Ám thick except beneath the processes where it may attain a thickness of 3 Ám. The type of wall ornamentation present between the processes is difficult to determine; the scanning electron microscope, however, clearly reveals that a complex series of ribs and corrugations are present (Pl.5, fig.3,4). The amount of ribbing on the processes varies from a little confined to the proximal region to text-fig.3 extensive longitudinal ones. Also, although the processes on most specimens are parallel sided (Pl.5, fig.5). The processes are arranged in an approximately circular manner around the cyst. It is, however, extremely difficult to locate the exact position of all the processes and to determine a cyst tabulation. Usually 20 to 21 large tubular processes are present together with approximately 4 sulcal processes. At the apex of the holotype (Text-fig.3) two processes are linked by a proximal membrane.
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