Back
Adeliesphaera
From Fensome et al., 2019:
Adeliesphaera, Bijl and Brinkhuis, 2015, p.92.
Type: Bijl and Brinkhuis, 2015 pl.2A–B, as Adeliesphaera ohanlonii.
---------------------------------------------------------------------------------------------------
Original description: [Bijl and Brinkhuis, 2015]:
Diagnosis: Spherical, proximate cysts of intermediate size. The cyst is bi-layered, with the two layers closely appressed. Outer wall is characterized by non-tabular ornamentation. While the globular geometry of the cyst and equidimensional outline of the operculum suggests no dorsal-ventral compression, Adeliesphaera gen. nov. does feature one or two antapical horns, typical for Areoligeraceae.
Tabulation is only indicated by the archeopyle. The shape of the archeopyle reflects a strongly asymmetrical 1′ apical plate (Plate III, A–D; Fig. 3) and the position of the sulcal notch shows a strong left-side offset, both suggestive of strong sinistral torsion of the epicyst.
The archeopyle is single polyplacoid, and involves the total loss of the apical series.
Description:
Proximate cysts with two closely appressed wall layers. The geometry of the cyst is quasi-spherical, with two marked antapical horns, of which the left antapical horn is always the largest. Because the wall ornamentation is non-tabular, the reflected sulcal, cingular and hyposomal tabulation of the cyst is unknown.
Tabulation 4′, 6″, Xc, Xs, X‴, X″″.
The archeopyle is single polyplacoid, involves the loss of the apical series, and the operculum is usually free.
Operculum shape is equidimensional, with slight angular edges.
Affinities:
Adeliesphaera gen. nov. differs from morphologically similar proximate genera such as Batiacasphaera Drugg, 1970 in the presence of one or two antapical horns, and the left-side offset sulcal notch. Areoligeraceae genera such as Areoligera (Lejeune- Carpentier, 1938) Williams and Downie, 1966 and Glaphyrocysta Stover and Evitt, 1978 have a lenticular geometry (Fig. 3) while Adeliesphaera is globular. Moreover, Areoligera and Glaphyrocysta feature distinct processes (Lejeune-Carpentier, 1938; Williams and Downie, 1966; Stover and Evitt., 1978), while Adeliesphaera gen. nov. is proximate. Schematophora Deflandre and Cookson, 1955 lacks processes but has penitabular ornamentation and is ‘subsphaerical’ (Deflandre and Cookson, 1955), both features that are absent on Adeliesphaera. Hemiplacophora Cookson and Eisenack, 1965 and Stoveracysta Clowes, 1985 are not dorso-ventrally flattened, but lack an offset sulcal notch, have a rather symmetric 1′ plate and generally lack prominent antapical horns. Moreover, these genera feature either penitabular or parasutural ornamentation, which Adeliesphaera gen. nov. lacks.
Adeliesphaera, Bijl and Brinkhuis, 2015, p.92.
Type: Bijl and Brinkhuis, 2015 pl.2A–B, as Adeliesphaera ohanlonii.
---------------------------------------------------------------------------------------------------
Original description: [Bijl and Brinkhuis, 2015]:
Diagnosis: Spherical, proximate cysts of intermediate size. The cyst is bi-layered, with the two layers closely appressed. Outer wall is characterized by non-tabular ornamentation. While the globular geometry of the cyst and equidimensional outline of the operculum suggests no dorsal-ventral compression, Adeliesphaera gen. nov. does feature one or two antapical horns, typical for Areoligeraceae.
Tabulation is only indicated by the archeopyle. The shape of the archeopyle reflects a strongly asymmetrical 1′ apical plate (Plate III, A–D; Fig. 3) and the position of the sulcal notch shows a strong left-side offset, both suggestive of strong sinistral torsion of the epicyst.
The archeopyle is single polyplacoid, and involves the total loss of the apical series.
Description:
Proximate cysts with two closely appressed wall layers. The geometry of the cyst is quasi-spherical, with two marked antapical horns, of which the left antapical horn is always the largest. Because the wall ornamentation is non-tabular, the reflected sulcal, cingular and hyposomal tabulation of the cyst is unknown.
Tabulation 4′, 6″, Xc, Xs, X‴, X″″.
The archeopyle is single polyplacoid, involves the loss of the apical series, and the operculum is usually free.
Operculum shape is equidimensional, with slight angular edges.
Affinities:
Adeliesphaera gen. nov. differs from morphologically similar proximate genera such as Batiacasphaera Drugg, 1970 in the presence of one or two antapical horns, and the left-side offset sulcal notch. Areoligeraceae genera such as Areoligera (Lejeune- Carpentier, 1938) Williams and Downie, 1966 and Glaphyrocysta Stover and Evitt, 1978 have a lenticular geometry (Fig. 3) while Adeliesphaera is globular. Moreover, Areoligera and Glaphyrocysta feature distinct processes (Lejeune-Carpentier, 1938; Williams and Downie, 1966; Stover and Evitt., 1978), while Adeliesphaera gen. nov. is proximate. Schematophora Deflandre and Cookson, 1955 lacks processes but has penitabular ornamentation and is ‘subsphaerical’ (Deflandre and Cookson, 1955), both features that are absent on Adeliesphaera. Hemiplacophora Cookson and Eisenack, 1965 and Stoveracysta Clowes, 1985 are not dorso-ventrally flattened, but lack an offset sulcal notch, have a rather symmetric 1′ plate and generally lack prominent antapical horns. Moreover, these genera feature either penitabular or parasutural ornamentation, which Adeliesphaera gen. nov. lacks.