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Canningia fairfieldensis
From Fensome et al., 2019:
Canningia fairfieldensis Willumsen, 2012, p.59–60, pl.2, figs.1–6.
Holotype: Willumsen, 2012, pl.2, figs.1–2; Fensome et al., 2019a, figs.12K–L. Age: Early Paleocene.
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).
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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.
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Comments Fensome et al., 2019a:
Willumsen (Citation2012, p. 59) indicated that the autophragm (i.e. endophragm in our terminology) in this species ‘is covered by numerous short isolated clavate processes which are partly interconnected distally [by] an irregular perforate periphragm’. The pericoel is typically narrow, bulging to form two antapical prominences, and the ornament and periphragm show no clear indication of paratabulation. This species is very similar to, and possibly a taxonomic junior synonym of, Canningia areolata, although the difference in age of the holotypes of the two species is considerable.
Stratigraphical occurrence. The species was originally described from the Early Palaeocene of New Zealand.
Canningia fairfieldensis Willumsen, 2012, p.59–60, pl.2, figs.1–6.
Holotype: Willumsen, 2012, pl.2, figs.1–2; Fensome et al., 2019a, figs.12K–L. Age: Early Paleocene.
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).
---------------------------------------------------------------------------------------------------
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.
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Comments Fensome et al., 2019a:
Willumsen (Citation2012, p. 59) indicated that the autophragm (i.e. endophragm in our terminology) in this species ‘is covered by numerous short isolated clavate processes which are partly interconnected distally [by] an irregular perforate periphragm’. The pericoel is typically narrow, bulging to form two antapical prominences, and the ornament and periphragm show no clear indication of paratabulation. This species is very similar to, and possibly a taxonomic junior synonym of, Canningia areolata, although the difference in age of the holotypes of the two species is considerable.
Stratigraphical occurrence. The species was originally described from the Early Palaeocene of New Zealand.