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Pseudoceratium aulaeum
From Fensome et al., 2019:
Pseudoceratium aulaeum Harding, 1990b, p.18, pl.1, figs.1–6 ex Harding in Williams et al., 1998, p.512.
Holotype: Harding, 1990b, pl.1, fig.1; Fensome et al., 2019a, fig.18O.
This name was not validly published in Harding (1990b) since the lodgement of the holotype was not specified (ICN Article 40.7). NIA.
Age: late Barremian.
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Original diagnosis: Harding, 1990, p.18
Shape: Ambitus typically ceratioid, with long apical horn and shorter antapical and postcingular horns. Epicyst longer than hypocyst by virtue of the long apical horn. Greatest width across post-cingular horn. Strong dorso-ventral compression.
Phragma: Autophragm ca. 0.2 µm thick, surface laevigate. Intratabular sculptural elements consist of irregularly distributed processes supporting an ectophragmal trabecular reticulum. Reticulum very variable, may be developed over the whole cyst (rare) or restricted to parts of the intratabular areas. Muri ca. 0.4 µm in diameter.
Paratabulation: Paratabulation corniform gonyaulacoid, expressed by parasutural areas devoid of sculpture: 4", 6", Xc, 7""", 1"""", 1p, Xs.
Archaeopyle: Type (tA), involving apical paraplates as a free, simple, polyplacoid operculum.
Paracingulum: Evidenced by lack of sculpture, individual paraplates not determined.
Parasulcus: Precise paratabulation not known, usually area of reduced sculpture, ai offset to the left.
Dimensions: Length, plus operculum (165) 144.1(130) µm. Width (56) 50.0 (39) µm. Length, less operculum (104) 89.8 (77) µm. Specimens = 29 (21).
Affinities:
Harding, 1990, p.18: This species has only been found in the presumed low-salinity assemblages of late Barremian age in the Warlingham borehole. It is distinguished from the other members of the genus by its surface sculpture. Most other species in the genus (including P. pelliferum) have intratabular processes of variable nature and of variable height but these are never connected distally by ectophragmal trabeculae as in P. auleum. Specimens identified as this new species were recorded by Lister & Batten (1988) as P. pelliferum.
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Comments Fensome et al., 2019a:
This species is difficult to compare with other species of Pseudoceratium because the type material is illustrated by scanning electron micrographs (SEMs). Paratabulation is evident on the SEMs. Harding (1990, p. 18) noted that the “Intratabular sculptural elements consist of irregularly distributed processes supporting an ectophragmal trabecular reticulum.”
Stratigraphical occurrence. Harding (1990, 1998) recorded this species from “presumed low-salinity” upper Barremian assemblages of England.
Pseudoceratium aulaeum Harding, 1990b, p.18, pl.1, figs.1–6 ex Harding in Williams et al., 1998, p.512.
Holotype: Harding, 1990b, pl.1, fig.1; Fensome et al., 2019a, fig.18O.
This name was not validly published in Harding (1990b) since the lodgement of the holotype was not specified (ICN Article 40.7). NIA.
Age: late Barremian.
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Original diagnosis: Harding, 1990, p.18
Shape: Ambitus typically ceratioid, with long apical horn and shorter antapical and postcingular horns. Epicyst longer than hypocyst by virtue of the long apical horn. Greatest width across post-cingular horn. Strong dorso-ventral compression.
Phragma: Autophragm ca. 0.2 µm thick, surface laevigate. Intratabular sculptural elements consist of irregularly distributed processes supporting an ectophragmal trabecular reticulum. Reticulum very variable, may be developed over the whole cyst (rare) or restricted to parts of the intratabular areas. Muri ca. 0.4 µm in diameter.
Paratabulation: Paratabulation corniform gonyaulacoid, expressed by parasutural areas devoid of sculpture: 4", 6", Xc, 7""", 1"""", 1p, Xs.
Archaeopyle: Type (tA), involving apical paraplates as a free, simple, polyplacoid operculum.
Paracingulum: Evidenced by lack of sculpture, individual paraplates not determined.
Parasulcus: Precise paratabulation not known, usually area of reduced sculpture, ai offset to the left.
Dimensions: Length, plus operculum (165) 144.1(130) µm. Width (56) 50.0 (39) µm. Length, less operculum (104) 89.8 (77) µm. Specimens = 29 (21).
Affinities:
Harding, 1990, p.18: This species has only been found in the presumed low-salinity assemblages of late Barremian age in the Warlingham borehole. It is distinguished from the other members of the genus by its surface sculpture. Most other species in the genus (including P. pelliferum) have intratabular processes of variable nature and of variable height but these are never connected distally by ectophragmal trabeculae as in P. auleum. Specimens identified as this new species were recorded by Lister & Batten (1988) as P. pelliferum.
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Comments Fensome et al., 2019a:
This species is difficult to compare with other species of Pseudoceratium because the type material is illustrated by scanning electron micrographs (SEMs). Paratabulation is evident on the SEMs. Harding (1990, p. 18) noted that the “Intratabular sculptural elements consist of irregularly distributed processes supporting an ectophragmal trabecular reticulum.”
Stratigraphical occurrence. Harding (1990, 1998) recorded this species from “presumed low-salinity” upper Barremian assemblages of England.