Back
Sangiorgia
Sangiorgia, Sluijs and Brinkhuis, 2024, p. 455-456.
----------------------------------------------------------------------------------------------
Original description: [Sluijs and Brinkhuis, 2024, p. 455-456]:
Sangiorgia gen. nov.
Type species. Sangiorgia pospelovae gen. et sp. nov.
(Plates 9, 10, S30, S31, S32, 33)
Derivation of name. Named for Francesca Sangiorgi in recognition of her achievements in marine palynology, at the Laboratory of Palaeobotany and Palynology, Department of Earth Sciences, Utrecht University, the Netherlands.
Diagnosis. Cysts proximochorate to skolochorate; intermediate to large in size, body subspherical, bearing isolated gonal, relatively large, solid processes, of which many, but typically not all, distally interconnect. Such processes are distally interconnected with ribbon-like features, sometimes evolved into “tramlines” typical for Nematosphaeropsis and sometime single connections such as in Cannosphaeropsis, and these connections may be locally clustered on larger portions of the cyst. Distally, the essentially “gonal” locations may be marked by trifurcate projections. Proximal markings between process bases absent or limited to faint parasutural lines; paratabulation standard sexiform gonyaulacacean; archeopyle precingular, Type P, operculum free.
Description.
Shape: body subspherical.
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 trifurcate (gonal) or bifurcate (intergonal). A variable portion of the processes distally link to form trabeculae that connect several processes, sometimes leading to a partial and incomplete parasutural network. Connections between processes may comprise one (as in Cannosphaeropsis) or two (as in Nematosphaeropsis) trabeculae.
Paratabulation: 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.
Size: medium.
Type species.
Sangiorgia pospelovae sp. nov. (this paper)
Other species.
Sangiorgia marretiae sp. nov. (this paper)
Remarks. Sangiorgia is a genus with the basic building plan of Spiniferites and allied genera. Systematically, it resembles Achomosphaera because of the sparse parasutural ornamentation but differs in having distal connections of only a portion of the gonal processes. In Nematosphaeropsis and Cannosphaeropsis, all processes are distally connected (simple, or by “tramlines”) to form a complete network around the central body, whereas only part of the processes are interconnected in Sangiorgia.
----------------------------------------------------------------------------------------------
Original description: [Sluijs and Brinkhuis, 2024, p. 455-456]:
Sangiorgia gen. nov.
Type species. Sangiorgia pospelovae gen. et sp. nov.
(Plates 9, 10, S30, S31, S32, 33)
Derivation of name. Named for Francesca Sangiorgi in recognition of her achievements in marine palynology, at the Laboratory of Palaeobotany and Palynology, Department of Earth Sciences, Utrecht University, the Netherlands.
Diagnosis. Cysts proximochorate to skolochorate; intermediate to large in size, body subspherical, bearing isolated gonal, relatively large, solid processes, of which many, but typically not all, distally interconnect. Such processes are distally interconnected with ribbon-like features, sometimes evolved into “tramlines” typical for Nematosphaeropsis and sometime single connections such as in Cannosphaeropsis, and these connections may be locally clustered on larger portions of the cyst. Distally, the essentially “gonal” locations may be marked by trifurcate projections. Proximal markings between process bases absent or limited to faint parasutural lines; paratabulation standard sexiform gonyaulacacean; archeopyle precingular, Type P, operculum free.
Description.
Shape: body subspherical.
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 trifurcate (gonal) or bifurcate (intergonal). A variable portion of the processes distally link to form trabeculae that connect several processes, sometimes leading to a partial and incomplete parasutural network. Connections between processes may comprise one (as in Cannosphaeropsis) or two (as in Nematosphaeropsis) trabeculae.
Paratabulation: 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.
Size: medium.
Type species.
Sangiorgia pospelovae sp. nov. (this paper)
Other species.
Sangiorgia marretiae sp. nov. (this paper)
Remarks. Sangiorgia is a genus with the basic building plan of Spiniferites and allied genera. Systematically, it resembles Achomosphaera because of the sparse parasutural ornamentation but differs in having distal connections of only a portion of the gonal processes. In Nematosphaeropsis and Cannosphaeropsis, all processes are distally connected (simple, or by “tramlines”) to form a complete network around the central body, whereas only part of the processes are interconnected in Sangiorgia.