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Apectodinium augustum
From Fensome et al., 2019:
Apectodinium augustum, (Harland, 1979c, p.63, pl.2, figs.13–15) Lentin and Williams, 1981, p.14.
Holotype: Harland, 1979c, pl.2, fig.13.
NOW Axiodinium.
Originally Wetzeliella subgenus Apectodinium, subsequently Apectodinium, thirdly (and now) Axiodinium.
Age: latest Paleocene.
Locus typicus: Northwest Europe
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Original description as Wetzeliella (Apectodinium) augusta: [Harland, 1979, p. 63]:
Diagnosis:
Large, pentagonal cavate cysts, with pericoel mainly developed beneath the horns. With or without an apical horn but characterised by long, up to three-quarters the diameter of the cyst, lateral horns and well developed asymmetrical antapical horns. Processes hollow, long, flexuous, simple, evexate or aculeate, randomly developed.
No tabulation discernible.
Archaeopyle I2a/I3a, ?reduced.
Description:
Wall layers thin, the endophragm often shows crumpling, closely adpressed but not actually adjoining; wall surfaces smooth to rough, possibly microgranulate. The endophragm separates from the periphragm at the horns but may also swell slightly into the horn pericoels. Cyst shape markedly pentagonal although some specimens exhibit a more rounded ambitus. Horn characteristic, although the development the apical horn is variable from being prominent to absent. The horns often show some branching and the antapical horns are asymmetrically developed, the left one being the better developed. All the horns bear processes. Press development shows a differentiation between shorter peripheral types and those towards the median-line of the cyst; processes are long between 1/15 and 1/4 cyst diameter, tubular, made up of periphragm, slender, tapering, sinuous, closed distally and bear, sometimes long, spines. The processes are apparently randomly distributed apart from sutural ones in the cingular area, where some branched complex processes my occur.
Variation: Intraspecific variation appears restricted to one of size and shape and to the development of the apical horn.
Dimensions:
Length: 60.0-75.0 µm; Breadth: 63.75-85.0 µm.
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Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Apectodinium augustum (Harland, 1979c) Lentin and Williams, 1981, is a large pentagonal cavate cyst, with pericoels mainly developed beneath the horns. With or without apical horn but characterised by long, up to three-quarters of the diameter of the cyst, lateral horns and well developed, asymmetrical antapical horns. Processes hollow, long, flexuous, simple, evexate or aculeate, randomly developed.
Size: pericyst length 60-75 µm, width 64-85 µm.
Apectodinium augustum, (Harland, 1979c, p.63, pl.2, figs.13–15) Lentin and Williams, 1981, p.14.
Holotype: Harland, 1979c, pl.2, fig.13.
NOW Axiodinium.
Originally Wetzeliella subgenus Apectodinium, subsequently Apectodinium, thirdly (and now) Axiodinium.
Age: latest Paleocene.
Locus typicus: Northwest Europe
---------------------------------------------------------------------------------------------------
Original description as Wetzeliella (Apectodinium) augusta: [Harland, 1979, p. 63]:
Diagnosis:
Large, pentagonal cavate cysts, with pericoel mainly developed beneath the horns. With or without an apical horn but characterised by long, up to three-quarters the diameter of the cyst, lateral horns and well developed asymmetrical antapical horns. Processes hollow, long, flexuous, simple, evexate or aculeate, randomly developed.
No tabulation discernible.
Archaeopyle I2a/I3a, ?reduced.
Description:
Wall layers thin, the endophragm often shows crumpling, closely adpressed but not actually adjoining; wall surfaces smooth to rough, possibly microgranulate. The endophragm separates from the periphragm at the horns but may also swell slightly into the horn pericoels. Cyst shape markedly pentagonal although some specimens exhibit a more rounded ambitus. Horn characteristic, although the development the apical horn is variable from being prominent to absent. The horns often show some branching and the antapical horns are asymmetrically developed, the left one being the better developed. All the horns bear processes. Press development shows a differentiation between shorter peripheral types and those towards the median-line of the cyst; processes are long between 1/15 and 1/4 cyst diameter, tubular, made up of periphragm, slender, tapering, sinuous, closed distally and bear, sometimes long, spines. The processes are apparently randomly distributed apart from sutural ones in the cingular area, where some branched complex processes my occur.
Variation: Intraspecific variation appears restricted to one of size and shape and to the development of the apical horn.
Dimensions:
Length: 60.0-75.0 µm; Breadth: 63.75-85.0 µm.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Apectodinium augustum (Harland, 1979c) Lentin and Williams, 1981, is a large pentagonal cavate cyst, with pericoels mainly developed beneath the horns. With or without apical horn but characterised by long, up to three-quarters of the diameter of the cyst, lateral horns and well developed, asymmetrical antapical horns. Processes hollow, long, flexuous, simple, evexate or aculeate, randomly developed.
Size: pericyst length 60-75 µm, width 64-85 µm.