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Liasidium variabile
Liasidium variabile Drugg, 1978
Holotype: Drugg 1978, pl.5, fig.9
Locus typicus: Balingen, Swabia, Germany
Stratum typicum: Sinemurian
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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.
Liasidium variabile Drugg, 1978, is broadly spindle-shaped with many having prominent shoulders. The apical horn is always well developed, from 10 to 32 µm long with an acuminate or blunt tip. One to three longitudinal ridges or striations are often present ventrally on the horn. The offset antapical horn is much shorter and is barely visible on some specimens. There is commonly a rudimentary second antapical horn. The left is always the longer. Cyst wall thin and chagrinate. Paracingulum clearly marked by low ridges. The archeopyle is large, intercalary, resulting from the loss of one plate. Size: length 36-120 µm, breadth 31-70 µm.
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Original description: Drugg, 1978, p. 69
Proximate cysts with a variable outline but most commonly broadly spindle-shaped. Many are prominently shouldered. The variation in outline is caused by the variable development of the shoulders and of the antapical horn or horns. The apical horn is always well-developed and ranges in length from 10 to 32 µm. The tip is usually acuminate but is sometimes blunted. One to three longitudinally ridges or striations are often present ventrally on the horn. The antapical horn is much shorter and is barely visible on some specimens. A rudimentary second antapical horn is commonly present. When two horns are present the right horn is the longer. When the second horn is absent there is usually an outward bulge of the cyst wall in the general area. All horns are basically hollow although sometimes the tips are filled with a dense reddish-brown material. The horns are often striate. The cyst wall is thin (a little less than 1 µm) and shagreen. The slightly laevorotatory paracingulum is clearly marked by low ridges and is 3 to 5 µm wide. The archeopyle is located high on the dorsal side and is quite large. Rare specimens which are apparently complete give the impression that the operculum is thinner than the rest of the body wall. Separated opercula have never been encountered even though the cysts are abundant. The archeopyle is probably formed by the loss of one large intercalary paraplate. On some specimens, however, the opening is so large that it is possible that two additional intercalary paraplates are involved. Seemingly one apical paraplate (3'?) sometimes takes part in archeopyle formation but does not always participate. Paratabulation is generally lacking. The size range is considerable. The overall length ranges from 36 to 120 µm and the width ranges from 31 to 70 µm.
Holotype: Drugg 1978, pl.5, fig.9
Locus typicus: Balingen, Swabia, Germany
Stratum typicum: Sinemurian
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Liasidium variabile Drugg, 1978, is broadly spindle-shaped with many having prominent shoulders. The apical horn is always well developed, from 10 to 32 µm long with an acuminate or blunt tip. One to three longitudinal ridges or striations are often present ventrally on the horn. The offset antapical horn is much shorter and is barely visible on some specimens. There is commonly a rudimentary second antapical horn. The left is always the longer. Cyst wall thin and chagrinate. Paracingulum clearly marked by low ridges. The archeopyle is large, intercalary, resulting from the loss of one plate. Size: length 36-120 µm, breadth 31-70 µm.
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Original description: Drugg, 1978, p. 69
Proximate cysts with a variable outline but most commonly broadly spindle-shaped. Many are prominently shouldered. The variation in outline is caused by the variable development of the shoulders and of the antapical horn or horns. The apical horn is always well-developed and ranges in length from 10 to 32 µm. The tip is usually acuminate but is sometimes blunted. One to three longitudinally ridges or striations are often present ventrally on the horn. The antapical horn is much shorter and is barely visible on some specimens. A rudimentary second antapical horn is commonly present. When two horns are present the right horn is the longer. When the second horn is absent there is usually an outward bulge of the cyst wall in the general area. All horns are basically hollow although sometimes the tips are filled with a dense reddish-brown material. The horns are often striate. The cyst wall is thin (a little less than 1 µm) and shagreen. The slightly laevorotatory paracingulum is clearly marked by low ridges and is 3 to 5 µm wide. The archeopyle is located high on the dorsal side and is quite large. Rare specimens which are apparently complete give the impression that the operculum is thinner than the rest of the body wall. Separated opercula have never been encountered even though the cysts are abundant. The archeopyle is probably formed by the loss of one large intercalary paraplate. On some specimens, however, the opening is so large that it is possible that two additional intercalary paraplates are involved. Seemingly one apical paraplate (3'?) sometimes takes part in archeopyle formation but does not always participate. Paratabulation is generally lacking. The size range is considerable. The overall length ranges from 36 to 120 µm and the width ranges from 31 to 70 µm.