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Australisphaera pannosa
Australisphaera pannosa, (Duxbury, 1980), Duxbury, 1983
Now Nyktericysta?. Originally Muderongia, subsequently Australisphaera, thirdly (and now) Nyktericysta?.
Holotype: Duxbury, 1980, pl.10, fig.3; text-fig.12B
Locus typicus: Speeton Clay, Speeton, England
Stratum typicum: Barremian
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Original description as Muderongia pannosa: [Duxbury, 1980, p. 129]:
Diagnosis:
A species of Muderongia which has a spheroidal to ovoidal, apparently single-layered body produced into five horns. There is a single apical horn, which is the longest of all, two broad, usually equal, short lateral horns, which are usually blunt-ended and distinctly notched distally, and two unequal antapical horns. The region between the antapical horns is distinctly concave.
The body surface has granular to spinose ornament which is locally dense along parasutural boundaries, marking out an apparently gonyaulacacean paratabulation scheme.
The paracingular and central paraplate areas are typically devoid of ornament.
The maximum height of body ornament is observed on the horn tips, where solid projections are present. Each solid projection displays fine, free or anastomising spines along its length. The lateral horns each display two solid projections at their extremes, one on each side of the paracingular notch, with the hypocystal projection the longer of the two.
The archeopyle is apical.
Dimensions:
Holotype (complete): 102 x 90 µm. Operculum detached: 75 (71) 64 x 104 (76) 64 µm.
Affinities:
The body ornament and general morphology of this species distinguish it from all others. Muderongia asymmetrica Brideaux, 1977 appears comparable, but the general inequality of the lateral horns and the smooth to granular body surface contrast with the- usually equal lateral horns and the granular to spinose or anastamosing/spinose ornament (all types seen on individual specimens) of M. pannosa. Also, those specimens of M. asymmetrica depicted by Brideaux (1977, pl. 15, figs. 9, 10) do not display the pronounced notching of the lateral horns seen in M. pannosa, nor do they possess solid projections at the horn tips.
Now Nyktericysta?. Originally Muderongia, subsequently Australisphaera, thirdly (and now) Nyktericysta?.
Holotype: Duxbury, 1980, pl.10, fig.3; text-fig.12B
Locus typicus: Speeton Clay, Speeton, England
Stratum typicum: Barremian
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Original description as Muderongia pannosa: [Duxbury, 1980, p. 129]:
Diagnosis:
A species of Muderongia which has a spheroidal to ovoidal, apparently single-layered body produced into five horns. There is a single apical horn, which is the longest of all, two broad, usually equal, short lateral horns, which are usually blunt-ended and distinctly notched distally, and two unequal antapical horns. The region between the antapical horns is distinctly concave.
The body surface has granular to spinose ornament which is locally dense along parasutural boundaries, marking out an apparently gonyaulacacean paratabulation scheme.
The paracingular and central paraplate areas are typically devoid of ornament.
The maximum height of body ornament is observed on the horn tips, where solid projections are present. Each solid projection displays fine, free or anastomising spines along its length. The lateral horns each display two solid projections at their extremes, one on each side of the paracingular notch, with the hypocystal projection the longer of the two.
The archeopyle is apical.
Dimensions:
Holotype (complete): 102 x 90 µm. Operculum detached: 75 (71) 64 x 104 (76) 64 µm.
Affinities:
The body ornament and general morphology of this species distinguish it from all others. Muderongia asymmetrica Brideaux, 1977 appears comparable, but the general inequality of the lateral horns and the smooth to granular body surface contrast with the- usually equal lateral horns and the granular to spinose or anastamosing/spinose ornament (all types seen on individual specimens) of M. pannosa. Also, those specimens of M. asymmetrica depicted by Brideaux (1977, pl. 15, figs. 9, 10) do not display the pronounced notching of the lateral horns seen in M. pannosa, nor do they possess solid projections at the horn tips.