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Trinovantedinium sterthense
From Fensome et al., 2019:
Trinovantedinium sterthense Head, 1993, p.41,44, fig.25, nos.2–11.
Holotype: Head, 1993, fig.25, nos.10–11.
Locus typicus: St. Erth Beds, Cornwell, SW England
Stratum typicum: Pliocene
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Original diagnosis: Head, 1993, p.43
Cysts light brown in color, moderately compressed dorsoventrally, with rounded pentagonal outline and wall formed of two closely appressed layers, outer being much thinner than inner. Horns rounded; the two antapical horns of approximately equal length. Wall surface smooth or has sparsely scattered granules and bears short unbranched processes with narrow stems that terminate distally as minute platforms. Processes distributed as single row along each margin of paracingulum (which may also be indicated by weak folding) and also concentrated on antapical and apical horns and near lateral ambitus in dorsoventral compression. Elsewhere processes absent or very sparsely distributed. Adjacent processes may show some linear alignment but no clear expression of paratabulation evident except along paracingulum. Archeopyle 2a hexa intercalary with short H3 and H5 sides; operculum free.
Original description: Head, 1993, p.43
Cysts generally dorsoventrally compressed. Cyst wall appears autophragmal in most specimens but in some, including holotype, slight separation (generally less than 1.5 Ám) of very thin periphragm (that bears processes) apparent at ambitus. Processes narrow (<1.0 Ám) for most of length, unbranched in all specimens seen, and terminate distally in small platforms of about 1.0 Ám diameter. Distal platforms centrally thickened and become thin towards (irregular?) margins which may be slightly recurved. Processes generally solid for most of length, but process bases may be expanded and hollow.
Dimensions.--Holotype: central body: length, 54 Ám; width, 53 Ám; average length of processes,6.5 Ám. Range: central body: length, 41(50.0)61 Ám; width, 45(49.6)53 Ám; average length of processes, 4.5(5.5)7.0 Ám. Eleven specimens were measured.
Affinities:
Head, 1993, p.44: This species differs from all others in the genus by having processes that are clustered in five areas, viz apical and antapical horn areas and the mid-lateral sides of the cyst. Quadrina? condita de Verteuil and Norris, 1992, has aculeate processes clustered in four areas of the cyst and lacks processes along the paracingular margins.
Trinovantedinium sterthense Head, 1993, p.41,44, fig.25, nos.2–11.
Holotype: Head, 1993, fig.25, nos.10–11.
Locus typicus: St. Erth Beds, Cornwell, SW England
Stratum typicum: Pliocene
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Original diagnosis: Head, 1993, p.43
Cysts light brown in color, moderately compressed dorsoventrally, with rounded pentagonal outline and wall formed of two closely appressed layers, outer being much thinner than inner. Horns rounded; the two antapical horns of approximately equal length. Wall surface smooth or has sparsely scattered granules and bears short unbranched processes with narrow stems that terminate distally as minute platforms. Processes distributed as single row along each margin of paracingulum (which may also be indicated by weak folding) and also concentrated on antapical and apical horns and near lateral ambitus in dorsoventral compression. Elsewhere processes absent or very sparsely distributed. Adjacent processes may show some linear alignment but no clear expression of paratabulation evident except along paracingulum. Archeopyle 2a hexa intercalary with short H3 and H5 sides; operculum free.
Original description: Head, 1993, p.43
Cysts generally dorsoventrally compressed. Cyst wall appears autophragmal in most specimens but in some, including holotype, slight separation (generally less than 1.5 Ám) of very thin periphragm (that bears processes) apparent at ambitus. Processes narrow (<1.0 Ám) for most of length, unbranched in all specimens seen, and terminate distally in small platforms of about 1.0 Ám diameter. Distal platforms centrally thickened and become thin towards (irregular?) margins which may be slightly recurved. Processes generally solid for most of length, but process bases may be expanded and hollow.
Dimensions.--Holotype: central body: length, 54 Ám; width, 53 Ám; average length of processes,6.5 Ám. Range: central body: length, 41(50.0)61 Ám; width, 45(49.6)53 Ám; average length of processes, 4.5(5.5)7.0 Ám. Eleven specimens were measured.
Affinities:
Head, 1993, p.44: This species differs from all others in the genus by having processes that are clustered in five areas, viz apical and antapical horn areas and the mid-lateral sides of the cyst. Quadrina? condita de Verteuil and Norris, 1992, has aculeate processes clustered in four areas of the cyst and lacks processes along the paracingular margins.