Back
Hafniasphaera australis
Hafniasphaera australis Guler et al., 2005, p.425,427, figs.5M–T,6A–E.
Holotype: Guler et al., 2005, figs.5S–T.
Age: Maastrichtian.
Original description (Guler et al., 2005):
Hafniasphaera australis sp. nov. Figures 5.M-T, 6.A-E
Holotype. Slide UNSLP 3427-1 37.1/95, EF: W37; Figs. 5.M-N.
Paratype. Slide UNSLP 3427-1 48/103.5, EF: N48/4; Figs. 5.S-T.
Type locality. Estancia 25 de Mayo, Cerro Calafate, south of Lago Argentino, Austral Basin.
Type horizon. Sample VG6, 165 m above the base of the section.
Etymology. Named after the Austral Basin, in reference to the provenance of the type material.
Diagnosis. A species of Hafniasphaera with spherical to subspherical, thick-walled central body, containing densely distributed vesicles about 0.5 µm in diameter. Gonal processes trifurcate, bifid with a prominent anterior ventral process emerging from the junction of the 1', 4' and as paraplates.
Description. Proximo-chorate to chorate cyst with a spherical to subspherical central body. Endophragm and periphragm appressed except at the base of the processes. Cyst wall with numerous, evenly distributed vesicles about 0.5 µm in diameter. Vesicles are interconnected, forming a fine internal reticulum. Processes contain a variable number of vesicles which are generally larger than the vesicles in the central body. Simple gonal processes only, trifurcate, bifid. Cingular processes are frequently connected by membranes, ramified in more complex ways (figure 5, Q-R). Central body with a paratabulation typical for the genus: 4´, 6´´, 6c, 5´´´, 1p, ps, 1´´´´. Paraplates 1' and 4' separated by a suture that is hardly observable. A distinctive process characterizes the ventral anterior area, rising from the junction of the 1', 4' and as paraplates. Archeopyle precingular (3''), operculum free, sometimes in situ .
Dimensions. Central body: length 42 (47.2) 55 µm; width 40 (42.9) 50 µm. Length of processes 8 to 20 µm (25 specimens measured).
Remarks. The specimens described above are similar to Hafniasphaera fluens Hansen, 1977 but differ by the presence of the distinctive process emerging from the anterior ventral area. Assemblages from an equivalent section to the studied area contain specimens of Hafniasphaera australis sp. nov. associated with Chattangiella tripartita (Cookson and Eisenack, 1960) Lentin and Williams, 1985 emend . Cookson and Manum, 1964.
Stratigraphic occurrence. Common to abundant in samples VG2, VG5, VG6 and VG7.
Holotype: Guler et al., 2005, figs.5S–T.
Age: Maastrichtian.
Original description (Guler et al., 2005):
Hafniasphaera australis sp. nov. Figures 5.M-T, 6.A-E
Holotype. Slide UNSLP 3427-1 37.1/95, EF: W37; Figs. 5.M-N.
Paratype. Slide UNSLP 3427-1 48/103.5, EF: N48/4; Figs. 5.S-T.
Type locality. Estancia 25 de Mayo, Cerro Calafate, south of Lago Argentino, Austral Basin.
Type horizon. Sample VG6, 165 m above the base of the section.
Etymology. Named after the Austral Basin, in reference to the provenance of the type material.
Diagnosis. A species of Hafniasphaera with spherical to subspherical, thick-walled central body, containing densely distributed vesicles about 0.5 µm in diameter. Gonal processes trifurcate, bifid with a prominent anterior ventral process emerging from the junction of the 1', 4' and as paraplates.
Description. Proximo-chorate to chorate cyst with a spherical to subspherical central body. Endophragm and periphragm appressed except at the base of the processes. Cyst wall with numerous, evenly distributed vesicles about 0.5 µm in diameter. Vesicles are interconnected, forming a fine internal reticulum. Processes contain a variable number of vesicles which are generally larger than the vesicles in the central body. Simple gonal processes only, trifurcate, bifid. Cingular processes are frequently connected by membranes, ramified in more complex ways (figure 5, Q-R). Central body with a paratabulation typical for the genus: 4´, 6´´, 6c, 5´´´, 1p, ps, 1´´´´. Paraplates 1' and 4' separated by a suture that is hardly observable. A distinctive process characterizes the ventral anterior area, rising from the junction of the 1', 4' and as paraplates. Archeopyle precingular (3''), operculum free, sometimes in situ .
Dimensions. Central body: length 42 (47.2) 55 µm; width 40 (42.9) 50 µm. Length of processes 8 to 20 µm (25 specimens measured).
Remarks. The specimens described above are similar to Hafniasphaera fluens Hansen, 1977 but differ by the presence of the distinctive process emerging from the anterior ventral area. Assemblages from an equivalent section to the studied area contain specimens of Hafniasphaera australis sp. nov. associated with Chattangiella tripartita (Cookson and Eisenack, 1960) Lentin and Williams, 1985 emend . Cookson and Manum, 1964.
Stratigraphic occurrence. Common to abundant in samples VG2, VG5, VG6 and VG7.