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Pseudoceratium toveae
Pseudoceratium toveae Nohr-Hansen, 1993
Holotype: Nohr-Hansen, 1993, pl. fig.2
Locus typicus: Section 1 north of Haystack, East Greenland
Stratum typicum: Upper Barremian to lowermost? Aptian
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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.
Pseudoceratium toveae Nøhr-Hansen, 1993. Diagnosis from Nøhr-Hansen (1983), Large, dorso-ventrally compressed ceratioid, proximate cyst, with three large horns. The cyst is two-layered with a smooth to microgranulate autophragm and an intratabular reticulate ectophragm, the autophragm and ectophragm are closely appressed. Tabulation is indicated by bold pandasutural areas. Archeopyle apical (type [tA]). This species differs from P.weymouthensis, which has weak tabulation, indicated by larger processes in the pandasutural areas, which according to Helby are apparently covered by a continuous ectophragm, and by its rather pronounced extension of the cingulum onto the anterior part of the postcingular horn. Size: loisthocyst length 99-165 µm, overall width 63-74 µm, overall length 193-250 µm, length of lateral horn 54-85 µm, length apical horn 68-119 µm, length antapical horn 54-99 µm.
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Original diagnosis: Nohr-Hansen, 1993, p.108
Large, dorso-ventrally compressed ceratioid, proximate cyst, with three large horns. The cyst is twolayered with a smooth to microgranulate autophragm and an intratabular reticulate ectophragm, the autophragm and ectophragm are closely adpressed. Tabulation is indicated by bold pandasutural areas. Archeopyle apical (type tA).
Original description: Nohr-Hansen, 1993, p.108
Cyst type. The cyst is proximate ceratioid.
Shape. The cyst has three long horns: one apical, one right lateral and one antapical. The angle between the horn is approximately 120¦.
Wall relationship. The cyst wall is two-layered, composed of closely adpressed autophragm and ectophragm.
Wall features. The autophragm, which is only visible on the pandasutural areas, has a smooth to microgranulate outer surface (Plate 22, Fig. 5). The ectophragm forming the ornamentation is restricted to the intratabular areas and is composed of low processes (less than 1 Á). The surface of the ectophragm is reticulate (Plate 22, Figs 5,7). The processes are of variable size often making it difficult to distinguish the two layers, especially on the horns.
Tabulation. The tabulation is expressed by the pandasutural areas which are devoid of the reticulate ectophragm, and by the archeopyle sutures. The cingular plates are occasionally distinguishable (Plate 22, Fig. 5) but no sulcal area has been observed. Tabulation formula: ?4', ?6", ?6s, ?6''', ?1p, 1''''.
Archeopyle. The archeopyle is apical (type tA).
Affinities:
Nohr-Hansen, 1993, p.108, 110: Pseudoceratium toveae sp. nov. resembles Pseudoceratium weymouthense in size and shape, described from the upper Tithonian to lower Berriasian of Australia by Helby (1987). However, P. weymouthens differs by its weak tabulation, indicated by larger processes in the pandasutural areas which, according to Helby (1987 p. 317), are apparently covered by a conbnuous ectophragm, and by its rather pronounced extension of the cingulum onto the anterior part of the post-cingular horn. Pseudoceratium toveae differs by its larger size and less pronounced reticulate ectophragm from P. aulaeum, described by Harding (1990) from a presumed low salinity assemblage of late Barremian age in the Warlingham borehole, England. Pseudoceratium toveae differs from P. gochtii Neale and Sarjeant (1962) by its lack of spines and by its larger horns. Duxbury (1977, p. 60) questioned the species P. gochtii and regarded Neale and Sarjeant's specimens as belonging in P. pelliferum.
The species Eopseudoceratium sp. cf. E. gochtii recorded from the Barremian of the District of Mackenzie by Brideaux and Myhr (1976), Brideaux (1975, plate 44.2, fig. 2) and Brideaux (1977, p. 14, plate 5, fig. 4), may belong to P. toveae but the available illustrations and description are insufficient for a close comparison.
Holotype: Nohr-Hansen, 1993, pl. fig.2
Locus typicus: Section 1 north of Haystack, East Greenland
Stratum typicum: Upper Barremian to lowermost? Aptian
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Pseudoceratium toveae Nøhr-Hansen, 1993. Diagnosis from Nøhr-Hansen (1983), Large, dorso-ventrally compressed ceratioid, proximate cyst, with three large horns. The cyst is two-layered with a smooth to microgranulate autophragm and an intratabular reticulate ectophragm, the autophragm and ectophragm are closely appressed. Tabulation is indicated by bold pandasutural areas. Archeopyle apical (type [tA]). This species differs from P.weymouthensis, which has weak tabulation, indicated by larger processes in the pandasutural areas, which according to Helby are apparently covered by a continuous ectophragm, and by its rather pronounced extension of the cingulum onto the anterior part of the postcingular horn. Size: loisthocyst length 99-165 µm, overall width 63-74 µm, overall length 193-250 µm, length of lateral horn 54-85 µm, length apical horn 68-119 µm, length antapical horn 54-99 µm.
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Original diagnosis: Nohr-Hansen, 1993, p.108
Large, dorso-ventrally compressed ceratioid, proximate cyst, with three large horns. The cyst is twolayered with a smooth to microgranulate autophragm and an intratabular reticulate ectophragm, the autophragm and ectophragm are closely adpressed. Tabulation is indicated by bold pandasutural areas. Archeopyle apical (type tA).
Original description: Nohr-Hansen, 1993, p.108
Cyst type. The cyst is proximate ceratioid.
Shape. The cyst has three long horns: one apical, one right lateral and one antapical. The angle between the horn is approximately 120¦.
Wall relationship. The cyst wall is two-layered, composed of closely adpressed autophragm and ectophragm.
Wall features. The autophragm, which is only visible on the pandasutural areas, has a smooth to microgranulate outer surface (Plate 22, Fig. 5). The ectophragm forming the ornamentation is restricted to the intratabular areas and is composed of low processes (less than 1 Á). The surface of the ectophragm is reticulate (Plate 22, Figs 5,7). The processes are of variable size often making it difficult to distinguish the two layers, especially on the horns.
Tabulation. The tabulation is expressed by the pandasutural areas which are devoid of the reticulate ectophragm, and by the archeopyle sutures. The cingular plates are occasionally distinguishable (Plate 22, Fig. 5) but no sulcal area has been observed. Tabulation formula: ?4', ?6", ?6s, ?6''', ?1p, 1''''.
Archeopyle. The archeopyle is apical (type tA).
Affinities:
Nohr-Hansen, 1993, p.108, 110: Pseudoceratium toveae sp. nov. resembles Pseudoceratium weymouthense in size and shape, described from the upper Tithonian to lower Berriasian of Australia by Helby (1987). However, P. weymouthens differs by its weak tabulation, indicated by larger processes in the pandasutural areas which, according to Helby (1987 p. 317), are apparently covered by a conbnuous ectophragm, and by its rather pronounced extension of the cingulum onto the anterior part of the post-cingular horn. Pseudoceratium toveae differs by its larger size and less pronounced reticulate ectophragm from P. aulaeum, described by Harding (1990) from a presumed low salinity assemblage of late Barremian age in the Warlingham borehole, England. Pseudoceratium toveae differs from P. gochtii Neale and Sarjeant (1962) by its lack of spines and by its larger horns. Duxbury (1977, p. 60) questioned the species P. gochtii and regarded Neale and Sarjeant's specimens as belonging in P. pelliferum.
The species Eopseudoceratium sp. cf. E. gochtii recorded from the Barremian of the District of Mackenzie by Brideaux and Myhr (1976), Brideaux (1975, plate 44.2, fig. 2) and Brideaux (1977, p. 14, plate 5, fig. 4), may belong to P. toveae but the available illustrations and description are insufficient for a close comparison.