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Canningia fairfieldensis
Canningia fairfieldensis, Willumsen, 2012, p.59–60, pl.2, figs.1–6.
Holotype: Willumsen, 2012, pl.2, figs.1–2
Paratype 1: Plate 2, figures 3, 6.; Paratype 2: Plate 2, figures 4, 5.
Type locality: Fairfield Quarry section, Dunedin, South Island, New Zealand.
Type stratum: Lower Paleocene strata of the Abbotsford Formation; Above horizon D in Fairfield Quarry, Dunedin, South Island, New Zealand
Stratigraphic occurrence: In Fairfield Quarry occurs consistently between 0.02 m to c. 0.995 m above the K-Pg boundary (Figure 4); in the mid-Waipara River section, the range is calibrated to the early Paleocene radiolarian zones RP1?–2 and foraminferal zones P0 to P1a–c (Figure 3).
Age: early Paleocene.
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Original description: [Willumsen, 2012]:
Diagnosis:
Medium-sized, subspherical cyst that is covered by numerous short isolated clavate processes which are partly interconnected distally forming an irregular perforate periphargm.
Paratabulation is only indicated by an apical, tA archeopyle and angular zig-zag suturs.
Description:
Proximochorate cyst of medium size with a subspherical shape.
Autophragm is smooth and covered by numerous short, solid, irregular dispersed clavate processes which are partly interconnected distally forming a foveolate periphragm.
Processes are 0.5–1.0 μm thick, up to 5–8 μm in height and they form a thin partly continuous perforate periphragm (Plate 2, figures 3–5).
The endo- and periphragm are most often closely appressed except from the apical and antapical area where the periphragm forms lobes (Plate 2, figures 3–5).
Paratabulation only indicated by an apical, type tA archeopyle. Suture is angular. Operculum is most often free.
Dimensions:
Specimens measured 10; length 67(75)85 μm; width 54(69)82 μm; length of processes 5(8)12 μm.
Affinities/Discussion:
Canningia fairfieldensis sp. nov. differs from the other species in this genus such as C. reticulata (Cookson and Eisenack 1960) by having a very closely appressed partly continuous perforate periphragm covering the mid-ventral and dorsal area of the cyst and the paratabulation is only indicated by the archeopyle margin. Moshkovitz and Habib (1993) illustrate a similar cyst as Riculacysta sp. A from the K-Pg boundary transition in Alabama and Georgia, USA. They placed this species in the genus Riculacysta based on the presence of mid-ventral and mid-dorsal processes that are interconnected by a thin foveolate periphragm.
Holotype: Willumsen, 2012, pl.2, figs.1–2
Paratype 1: Plate 2, figures 3, 6.; Paratype 2: Plate 2, figures 4, 5.
Type locality: Fairfield Quarry section, Dunedin, South Island, New Zealand.
Type stratum: Lower Paleocene strata of the Abbotsford Formation; Above horizon D in Fairfield Quarry, Dunedin, South Island, New Zealand
Stratigraphic occurrence: In Fairfield Quarry occurs consistently between 0.02 m to c. 0.995 m above the K-Pg boundary (Figure 4); in the mid-Waipara River section, the range is calibrated to the early Paleocene radiolarian zones RP1?–2 and foraminferal zones P0 to P1a–c (Figure 3).
Age: early Paleocene.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Willumsen, 2012]:
Diagnosis:
Medium-sized, subspherical cyst that is covered by numerous short isolated clavate processes which are partly interconnected distally forming an irregular perforate periphargm.
Paratabulation is only indicated by an apical, tA archeopyle and angular zig-zag suturs.
Description:
Proximochorate cyst of medium size with a subspherical shape.
Autophragm is smooth and covered by numerous short, solid, irregular dispersed clavate processes which are partly interconnected distally forming a foveolate periphragm.
Processes are 0.5–1.0 μm thick, up to 5–8 μm in height and they form a thin partly continuous perforate periphragm (Plate 2, figures 3–5).
The endo- and periphragm are most often closely appressed except from the apical and antapical area where the periphragm forms lobes (Plate 2, figures 3–5).
Paratabulation only indicated by an apical, type tA archeopyle. Suture is angular. Operculum is most often free.
Dimensions:
Specimens measured 10; length 67(75)85 μm; width 54(69)82 μm; length of processes 5(8)12 μm.
Affinities/Discussion:
Canningia fairfieldensis sp. nov. differs from the other species in this genus such as C. reticulata (Cookson and Eisenack 1960) by having a very closely appressed partly continuous perforate periphragm covering the mid-ventral and dorsal area of the cyst and the paratabulation is only indicated by the archeopyle margin. Moshkovitz and Habib (1993) illustrate a similar cyst as Riculacysta sp. A from the K-Pg boundary transition in Alabama and Georgia, USA. They placed this species in the genus Riculacysta based on the presence of mid-ventral and mid-dorsal processes that are interconnected by a thin foveolate periphragm.