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Heteraulacacysta reticulata
Original description Iakovleva, 2025:
Heteraulacacysta reticulata sp. nov.
Plate VI, 1–12, 16; Plate VII, 1–8, 10–11.
Etymology: Named in reference to the distinct reticulate periphragm.
Type locality and horizon: Sample A10069, level 100,69 m, Alano di Piave section, Italy.
Holotype: Plate VI, figs. 1, 4, 7, 10; Sample A10069, slide 2, EF: O31–4.
Paratype 1: Plate VII, figs. 1, 4, 7, 10–11; Sample A7801, slide 2, EF: C20–3.
Paratype 2: Plate VI, figs. 2–3, 5–6, 8–9, 11; Sample A8761, slide 2, EF: S17–3.
Studied material: Alano di Piave section, Italy.
Stratigraphic horizon: Early Priabonian.
Diagnosis: A species of Heteraulacacysta characterized by very thin wall layers, typically with a distinctly mircoreticulate periphragm between the parasutural ridges or septae. Archeopyle epicystal, Type tAtP. The reflected paratabulation (‘quinqueform’, ‘exsert’, sensu Evitt, 1985) clearly supports assignment to the Goniodomidae.
Description:
Shape: (sub)sphaerical; outline circular to oval in apical/antapical view; combination epicystal archeopyle, Type (tAtP).
Wall relationships: Two wall layers are apparent; a thin endophragm and a periphragm are closely appressed over large parts of the cysts (in Bujak's 1980 terms ‘autophragm’). The periphragm displays distinct microreticulation.
Wall features: The endophragm appears completely smooth to psilate, while the periphragm is (micro) reticulated.
Processes: Absent.
Paratabulation: Indicated by distinct parasutural ridges or septae, and the tAtP archaeopyle.
Archeopyle: Formed by the release of all the apical and precingular paraplates (tAtP, compound).
Paracingulum: Clearly featured by septa formed by the periphragm.
Parasulcus: Indicated by septae only.
Dimensions: Holotype. 61 × 77 μm; Paratype 1. 62 × 75 μm. Total length/width 58 × 85 μm (10 specimens).
Comparison: Wall morphologies, ultrastructure, and wall relationships in Heteraulacacysta and in the very similar genus Dinopterygium (Deflandre 1935) Stover and Evitt, 1978 are quite unclear for most species of this group of Goniodomidae. SEM/TEM analyses will be required to fully resolve such issues. For now, the (micro) reticulation separates H. reticulata from all other species of this genus.
Heteraulacacysta reticulata sp. nov.
Plate VI, 1–12, 16; Plate VII, 1–8, 10–11.
Etymology: Named in reference to the distinct reticulate periphragm.
Type locality and horizon: Sample A10069, level 100,69 m, Alano di Piave section, Italy.
Holotype: Plate VI, figs. 1, 4, 7, 10; Sample A10069, slide 2, EF: O31–4.
Paratype 1: Plate VII, figs. 1, 4, 7, 10–11; Sample A7801, slide 2, EF: C20–3.
Paratype 2: Plate VI, figs. 2–3, 5–6, 8–9, 11; Sample A8761, slide 2, EF: S17–3.
Studied material: Alano di Piave section, Italy.
Stratigraphic horizon: Early Priabonian.
Diagnosis: A species of Heteraulacacysta characterized by very thin wall layers, typically with a distinctly mircoreticulate periphragm between the parasutural ridges or septae. Archeopyle epicystal, Type tAtP. The reflected paratabulation (‘quinqueform’, ‘exsert’, sensu Evitt, 1985) clearly supports assignment to the Goniodomidae.
Description:
Shape: (sub)sphaerical; outline circular to oval in apical/antapical view; combination epicystal archeopyle, Type (tAtP).
Wall relationships: Two wall layers are apparent; a thin endophragm and a periphragm are closely appressed over large parts of the cysts (in Bujak's 1980 terms ‘autophragm’). The periphragm displays distinct microreticulation.
Wall features: The endophragm appears completely smooth to psilate, while the periphragm is (micro) reticulated.
Processes: Absent.
Paratabulation: Indicated by distinct parasutural ridges or septae, and the tAtP archaeopyle.
Archeopyle: Formed by the release of all the apical and precingular paraplates (tAtP, compound).
Paracingulum: Clearly featured by septa formed by the periphragm.
Parasulcus: Indicated by septae only.
Dimensions: Holotype. 61 × 77 μm; Paratype 1. 62 × 75 μm. Total length/width 58 × 85 μm (10 specimens).
Comparison: Wall morphologies, ultrastructure, and wall relationships in Heteraulacacysta and in the very similar genus Dinopterygium (Deflandre 1935) Stover and Evitt, 1978 are quite unclear for most species of this group of Goniodomidae. SEM/TEM analyses will be required to fully resolve such issues. For now, the (micro) reticulation separates H. reticulata from all other species of this genus.