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Sangiorgia pospelovae
Original description: [Sluijs and Brinkhuis, 2024, p. 456]:
Sangiorgia pospelovae gen. et sp. nov.
Plates 9, 10, S30, S31, S32, 33
Derivation of name. Named for Vera Pospelova in recognition of her achievements in marine palynology, at the Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, USA.
Diagnosis. Cysts skolochorate; intermediate to large; body subspherical; bearing isolated essentially gonal; relatively large, solid, processes, of which many, but typically not all, distally interconnect. The distal connections are formed by ribbon-like features, typical for Cannosphaeropsis, sometimes evolved into “tramlines” typical for Nematosphaeropsis. The distally interconnected processes typically form clusters, giving the cysts an irregular outline. Proximal markings between process bases are absent or limited to faint parasutural lines; paratabulation standard sexiform gonyaulacacean; archeopyle precingular, Type P, operculum free.
Holotype. Plate 9, A–D
Paratypes. Plate 9, E–H, I–L; Plate 10, E–H
Material. IODP 302 Hole M0004A, Lomonosov Ridge, Arctic Ocean
Type locality and horizon. IODP 302 Hole M0004A, Lomonosov Ridge, Arctic Ocean, lower Eocene, cores 302-0004A-28X-2-130/132
Age. Early Eocene
Description.
Shape: central body subspherical, outline skolochorate, but irregular in consequence of sets of groups of clustered, distally partially connected processes, combined with occasional single, distally not connected gonal processes.
Wall relationships: autophragm only, or endophragm and periphragm “appressed” between processes.
Wall features: autophragm smooth or faintly ornamented. Parasutural features between process bases faint (e.g., traces of low ridges) or absent altogether; features may be present over entire cyst or only locally.
Processes: gonal only, or gonal and intergonal; tips of unconnected processes may distally be broadly trifurcate (gonal) or bifurcate (intergonal). A variable portion (“sets”) of processes distally link to form rather thick trabeculae that connect several processes, sometimes leading to a partial and incomplete distal parasutural network. Connections between (sets of) processes may comprise one (as in Cannosphaeropsis) or two (as in Nematosphaeropsis) trabeculae.
Paratabulation: positions of gonal processes and faint sutural ornamentation indicate standard sexiform gonyaulacacean tabulation.
Archeopyle: precingular, Type P (3” only); operculum free.
Paracingulum: indicated, if at all, by parasutural lines and position of gonal processes.
Parasulcus: indicated, if at all, by parasutural lines.
Dimensions. central body 35(40)42 (L) ×30(38)40 (W) (n = 10); total dimensions 60(70)77 (L) ×63(68)75 (W)
Holotype. Central body/total: 40/70 µm (L) ×38/68 µm (W).
Paratypes. Central body/total: 35/77 (L) ×30/63 (W) µm, central body/total: 40/70 (L) µm ×40/70 (W) µm, central body/total: 42/68 (L) µm ×36/70 (W) µm
Stratigraphic range/occurrence. Early Eocene
Remarks. Sangiorgia pospelovae somewhat resembles Achomosphaera alcicornu in overall character but has distinctly distally connected (sets of) processes. It differs from S. marretiae in being more robust and larger, having rather thick trabeculae, but foremost in the distinct lack of tri- or bifurcated processes positioned distally on top of the connecting trabeculae, “barbed wire style”.
Sangiorgia pospelovae gen. et sp. nov.
Plates 9, 10, S30, S31, S32, 33
Derivation of name. Named for Vera Pospelova in recognition of her achievements in marine palynology, at the Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, USA.
Diagnosis. Cysts skolochorate; intermediate to large; body subspherical; bearing isolated essentially gonal; relatively large, solid, processes, of which many, but typically not all, distally interconnect. The distal connections are formed by ribbon-like features, typical for Cannosphaeropsis, sometimes evolved into “tramlines” typical for Nematosphaeropsis. The distally interconnected processes typically form clusters, giving the cysts an irregular outline. Proximal markings between process bases are absent or limited to faint parasutural lines; paratabulation standard sexiform gonyaulacacean; archeopyle precingular, Type P, operculum free.
Holotype. Plate 9, A–D
Paratypes. Plate 9, E–H, I–L; Plate 10, E–H
Material. IODP 302 Hole M0004A, Lomonosov Ridge, Arctic Ocean
Type locality and horizon. IODP 302 Hole M0004A, Lomonosov Ridge, Arctic Ocean, lower Eocene, cores 302-0004A-28X-2-130/132
Age. Early Eocene
Description.
Shape: central body subspherical, outline skolochorate, but irregular in consequence of sets of groups of clustered, distally partially connected processes, combined with occasional single, distally not connected gonal processes.
Wall relationships: autophragm only, or endophragm and periphragm “appressed” between processes.
Wall features: autophragm smooth or faintly ornamented. Parasutural features between process bases faint (e.g., traces of low ridges) or absent altogether; features may be present over entire cyst or only locally.
Processes: gonal only, or gonal and intergonal; tips of unconnected processes may distally be broadly trifurcate (gonal) or bifurcate (intergonal). A variable portion (“sets”) of processes distally link to form rather thick trabeculae that connect several processes, sometimes leading to a partial and incomplete distal parasutural network. Connections between (sets of) processes may comprise one (as in Cannosphaeropsis) or two (as in Nematosphaeropsis) trabeculae.
Paratabulation: positions of gonal processes and faint sutural ornamentation indicate standard sexiform gonyaulacacean tabulation.
Archeopyle: precingular, Type P (3” only); operculum free.
Paracingulum: indicated, if at all, by parasutural lines and position of gonal processes.
Parasulcus: indicated, if at all, by parasutural lines.
Dimensions. central body 35(40)42 (L) ×30(38)40 (W) (n = 10); total dimensions 60(70)77 (L) ×63(68)75 (W)
Holotype. Central body/total: 40/70 µm (L) ×38/68 µm (W).
Paratypes. Central body/total: 35/77 (L) ×30/63 (W) µm, central body/total: 40/70 (L) µm ×40/70 (W) µm, central body/total: 42/68 (L) µm ×36/70 (W) µm
Stratigraphic range/occurrence. Early Eocene
Remarks. Sangiorgia pospelovae somewhat resembles Achomosphaera alcicornu in overall character but has distinctly distally connected (sets of) processes. It differs from S. marretiae in being more robust and larger, having rather thick trabeculae, but foremost in the distinct lack of tri- or bifurcated processes positioned distally on top of the connecting trabeculae, “barbed wire style”.