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Cornudinium stavelyense
Cornudinium stavelyense Pocock, 1972
Lentin and Williams, 1989, based on informalion from Jansonius, stated that the age of the type material is Late Callovian-Oxfordian.
Holotype: Pocock, 1972, pl.24, fig.15; Jansonius, 1986, pl.5, fig.7-8
Locus typicus: Western Canada
Stratum typicum:Swift Formation, Late Bajocian, Jurassic
Original description: Pocock 1972, p. 94
Vesicle biconical, the cones being joined mouth to mouth; epitheca elongate; somewhat asymmetric, one side being straight, the other exhibiting a distinct break of slope corresponding to the base of the epithecal spine; hypotheca relatively shorter than epitheca; outline symmetrical; epithecal edge of transverse furrow marked by a belt of thickening separating hypotheca from epitheca; remainder of furrow only visible on corroded specimens where a part of the thick external ornamentation has been removed (fig. 24); furrow about 14.0 Á wide; longitudinal furrow obscure; plating absent; epitheca shows two longitudinal lines of ornamentation:
1. An area of closely packed, irregular, anastomosing verrucae up to 2.0Á high giving the surface a very roughened appearance.
2. A somewhat smaller area of reduced, scabrate to granulose ornament which is an area of thinning of the vesicle wall, the area of greatest reduction of ornament being the area of greatest thinning; the area is torn on some specimens, suggesting that it may function as archeopyle.
Hypotheca much thickened and strongly ornamented, the ornamentation having a spongy appearance with irregular strands of tissue projecting at random from-the main mass; the removal of much of the ornament from corroded specimens with no associated damage to the rest of the thecal wall suggests that it forms a distinct second layer to the grain; colour yellow-brown; length 87.0 (100.4) 144.0Á; width 47.0 (56.0) 69.0Á; length of epithecal horn 21.0 (33.7) 45.0Á; length of epitheca 42.0 (59.4) 84.0Á; length of hypotheca 36.0 (49.6) 63.0Á.
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Supplemental description: Jansonius, 1986, p.205
(Holotype) 107 x 57 Ám, biconical cyst, the epicyst more elongate than the hypocyst. Wall appears essentially single-layered, although it can be described as two-layered if the heavy overlay of sculpture is taken as a separate layer. No central body can be discerned. A thin, roughened to faintly granular, clear layer of material is overlain by differential amounts of much coarser granular material, that produces an amber hue in great thickness. The thickest encrustation by this material is immediately over the cingulum, and in several discrete pads on the hypocyst, the pads appearing to be intratabular(?) and to correspond to a peridinioid plating pattern; these pads are clearly separated by strips of much less encrustation. On the epicyst, an oval area lacks sculpture; it corresponds to a 2a intercalary plate position. The remainder of the epicyst is thickened in a fairly uniform manner, although some thickenings appear to correspond to discrete plate areas. The apical horn is strengthened by two lateral, and one ventral, solid ridges of thicker material and is crowned by some stacked solid granules. (In other specimens these apical ridges are not always so strongly developed.) A cluster of micropyrite crystals is preserved inside the vesicle.
Lentin and Williams, 1989, based on informalion from Jansonius, stated that the age of the type material is Late Callovian-Oxfordian.
Holotype: Pocock, 1972, pl.24, fig.15; Jansonius, 1986, pl.5, fig.7-8
Locus typicus: Western Canada
Stratum typicum:Swift Formation, Late Bajocian, Jurassic
Original description: Pocock 1972, p. 94
Vesicle biconical, the cones being joined mouth to mouth; epitheca elongate; somewhat asymmetric, one side being straight, the other exhibiting a distinct break of slope corresponding to the base of the epithecal spine; hypotheca relatively shorter than epitheca; outline symmetrical; epithecal edge of transverse furrow marked by a belt of thickening separating hypotheca from epitheca; remainder of furrow only visible on corroded specimens where a part of the thick external ornamentation has been removed (fig. 24); furrow about 14.0 Á wide; longitudinal furrow obscure; plating absent; epitheca shows two longitudinal lines of ornamentation:
1. An area of closely packed, irregular, anastomosing verrucae up to 2.0Á high giving the surface a very roughened appearance.
2. A somewhat smaller area of reduced, scabrate to granulose ornament which is an area of thinning of the vesicle wall, the area of greatest reduction of ornament being the area of greatest thinning; the area is torn on some specimens, suggesting that it may function as archeopyle.
Hypotheca much thickened and strongly ornamented, the ornamentation having a spongy appearance with irregular strands of tissue projecting at random from-the main mass; the removal of much of the ornament from corroded specimens with no associated damage to the rest of the thecal wall suggests that it forms a distinct second layer to the grain; colour yellow-brown; length 87.0 (100.4) 144.0Á; width 47.0 (56.0) 69.0Á; length of epithecal horn 21.0 (33.7) 45.0Á; length of epitheca 42.0 (59.4) 84.0Á; length of hypotheca 36.0 (49.6) 63.0Á.
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Supplemental description: Jansonius, 1986, p.205
(Holotype) 107 x 57 Ám, biconical cyst, the epicyst more elongate than the hypocyst. Wall appears essentially single-layered, although it can be described as two-layered if the heavy overlay of sculpture is taken as a separate layer. No central body can be discerned. A thin, roughened to faintly granular, clear layer of material is overlain by differential amounts of much coarser granular material, that produces an amber hue in great thickness. The thickest encrustation by this material is immediately over the cingulum, and in several discrete pads on the hypocyst, the pads appearing to be intratabular(?) and to correspond to a peridinioid plating pattern; these pads are clearly separated by strips of much less encrustation. On the epicyst, an oval area lacks sculpture; it corresponds to a 2a intercalary plate position. The remainder of the epicyst is thickened in a fairly uniform manner, although some thickenings appear to correspond to discrete plate areas. The apical horn is strengthened by two lateral, and one ventral, solid ridges of thicker material and is crowned by some stacked solid granules. (In other specimens these apical ridges are not always so strongly developed.) A cluster of micropyrite crystals is preserved inside the vesicle.