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Canningia diastatikos
From Fensome et al., 2019:
Canningia diastatikos McLachlan et al., 2018, p.675–679, pl.2, figs.1–9; pl.3, figs.1–9; text-figs.4A–B,5A–B.
Holotype: McLachlan et al., 2018, pl.2, figs.1–5.
Age: Campanian.
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Original description McLachlan et al., 2018:
Canningia diastatikos sp. nov. Plate 2, figures 1–9; Plate 3, figures 1–9; Figures 4A, B and 5A, B
Holotype. The holotype (Plate 2, figures 1–5, sample 14-273, slide A, England Finder reference V38/3) is housed in the Paleoenvironmental and Marine Palynology Laboratory, School of Earth and Ocean Sciences, University of Victoria.
Paratypes. The cyst body (Plate 2, figures 7–9, sample 16- 368, slide E, England Finder reference W33/3; Plate 3, figures 1–3, sample 14-273, slide A, England Finder reference T44/1; Plate 3, figures 4–6, sample 14-273, slide B, England Finder reference M44/1; Plate 3, figures 7–9, sample 14-273, slide A, England Finder reference G41/1) and operculum (Plate 2, figure 6, sample 16-368, slide A, England Finder reference
S38/2) paratype specimens are housed in the Paleoenvironmental and Marine Palynology Laboratory, School of Earth and Ocean Sciences, University of Victoria.
Type locality. Collishaw Point, Hornby Island, British Columbia.
Diagnosis. A species of Canningia that is proximochorate, with subpentagonal to pentagonal autophragm ambitus. Holocavate. Wall layers closely appressed in mid-dorsal and mid-ventral areas. Ectophragm perforate, fenestrate, supported by membranous processes largely constrained to the ambital regions. Archaeopyle apical, with formula A(1–4’).
Description. Cyst proximochorate, with subpentagonal to pentagonal ambitus. Holocavate along ambital margins with closely appressed wall layers in mid-dorsal and mid-ventral areas. Archaeopyle apical, with formula A(1–4’); operculum detached leaving zigzag archaeopyle margin. Inferred reflected tabulation formula 4’, 6",? 6c, 6’’’, 1p, 1’’’’. Ectophragm comprising a perforate, fenestrate membrane (Plate 2, figure 4) supported by membranous columnar to taeniate, ribbon-like processes largely constrained to the ambital regions. Autophragm and ectophragm (both typically 0.5 lm thick) appressed on mid-dorsal and mid- ventral surfaces where processes are sparse or absent. Dorsal and ventral surfaces marked by fine granulation. Apical, lateral and antapical horns well-developed. Antapex asymmetrical with the left antapical horn longer than the right, the former often attaining twice the length of the latter. Tabulation sporadically indicated by processes alignment and ectophragm folding in ambital regions.
Dimensions.
Outer body width: 75.3 (105) 133 lm; holotype: 94.7 lm; number of specimens: 53.
Inner body width: 61.6 (90.1) 116.9 lm; holotype: 77.2 lm; number of specimens: 55.
Outer body length: 58.2 (79.8) 103.5 lm; holotype: 80 lm; number of specimens: 59
Inner body length: 51 (71.4) 93.1 lm; holotype: 71.2 lm; number of specimens: 62.
Left antapical horn length: 6.6 (15.6) 25.6 lm; holotype: 15.11 lm; number of specimens: 61.
Right antapical horn length: 2.3 (5.8) 16 lm; holotype: 7.17 lm; number of specimens: 61.
Opercular outer wall length: 43.3 (50.4) 57.5 lm; number of specimens: 2.
Opercular inner wall length: 42.2 (44.6) 47 lm; number of specimens: 2.
Comparison. Typical forms of Canningia diastatikos most resemble Canningia grandis which has a similar ectophragmal reticulum. However, Canningia diastatikos differs in that extensive ectophragm relief and separation are restricted to the ambital margins; in addition, there is typically greater separation between the autophragm and ectophragm in Canningia diastatikos. Canningia bassensis also has separation of wall layers restricted to the ambital margins, but has an ectophragm that occurs in elevated patches resulting in a clearly discernable cingulum indicated by transverse sutural folds. Rare specimens of Canningia diastatikos with closely appressed wall layers (Plate 3, figures 4–6) bear low-relief ornamentation similar to that of Canningia reticulata. Canningia diastatikos exhib- its greater development and projection of the lateral and antapical horns than any other species belonging to the genus.
Derivation of name. From the Latin diastatikos, meaning disjunct or separate, in reference to the disparity in ornamentation and ectocoel separation between lateral and medial regions.
Occurrence. Canningia diastatikos is present in the assemblages from 107 to 372 m in the Northumberland Formation section exposed from Phipps Point northward to Collishaw Point. Canningia diastatikos is most abundant in the uppermost 20–30 m of the Northumberland Formation section at Collishaw Point. The only other occurrence is from a single specimen some 250 m down-section. This isolated specimen also exhibits the smallest overall dimensions recorded for the species.
Canningia diastatikos McLachlan et al., 2018, p.675–679, pl.2, figs.1–9; pl.3, figs.1–9; text-figs.4A–B,5A–B.
Holotype: McLachlan et al., 2018, pl.2, figs.1–5.
Age: Campanian.
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Original description McLachlan et al., 2018:
Canningia diastatikos sp. nov. Plate 2, figures 1–9; Plate 3, figures 1–9; Figures 4A, B and 5A, B
Holotype. The holotype (Plate 2, figures 1–5, sample 14-273, slide A, England Finder reference V38/3) is housed in the Paleoenvironmental and Marine Palynology Laboratory, School of Earth and Ocean Sciences, University of Victoria.
Paratypes. The cyst body (Plate 2, figures 7–9, sample 16- 368, slide E, England Finder reference W33/3; Plate 3, figures 1–3, sample 14-273, slide A, England Finder reference T44/1; Plate 3, figures 4–6, sample 14-273, slide B, England Finder reference M44/1; Plate 3, figures 7–9, sample 14-273, slide A, England Finder reference G41/1) and operculum (Plate 2, figure 6, sample 16-368, slide A, England Finder reference
S38/2) paratype specimens are housed in the Paleoenvironmental and Marine Palynology Laboratory, School of Earth and Ocean Sciences, University of Victoria.
Type locality. Collishaw Point, Hornby Island, British Columbia.
Diagnosis. A species of Canningia that is proximochorate, with subpentagonal to pentagonal autophragm ambitus. Holocavate. Wall layers closely appressed in mid-dorsal and mid-ventral areas. Ectophragm perforate, fenestrate, supported by membranous processes largely constrained to the ambital regions. Archaeopyle apical, with formula A(1–4’).
Description. Cyst proximochorate, with subpentagonal to pentagonal ambitus. Holocavate along ambital margins with closely appressed wall layers in mid-dorsal and mid-ventral areas. Archaeopyle apical, with formula A(1–4’); operculum detached leaving zigzag archaeopyle margin. Inferred reflected tabulation formula 4’, 6",? 6c, 6’’’, 1p, 1’’’’. Ectophragm comprising a perforate, fenestrate membrane (Plate 2, figure 4) supported by membranous columnar to taeniate, ribbon-like processes largely constrained to the ambital regions. Autophragm and ectophragm (both typically 0.5 lm thick) appressed on mid-dorsal and mid- ventral surfaces where processes are sparse or absent. Dorsal and ventral surfaces marked by fine granulation. Apical, lateral and antapical horns well-developed. Antapex asymmetrical with the left antapical horn longer than the right, the former often attaining twice the length of the latter. Tabulation sporadically indicated by processes alignment and ectophragm folding in ambital regions.
Dimensions.
Outer body width: 75.3 (105) 133 lm; holotype: 94.7 lm; number of specimens: 53.
Inner body width: 61.6 (90.1) 116.9 lm; holotype: 77.2 lm; number of specimens: 55.
Outer body length: 58.2 (79.8) 103.5 lm; holotype: 80 lm; number of specimens: 59
Inner body length: 51 (71.4) 93.1 lm; holotype: 71.2 lm; number of specimens: 62.
Left antapical horn length: 6.6 (15.6) 25.6 lm; holotype: 15.11 lm; number of specimens: 61.
Right antapical horn length: 2.3 (5.8) 16 lm; holotype: 7.17 lm; number of specimens: 61.
Opercular outer wall length: 43.3 (50.4) 57.5 lm; number of specimens: 2.
Opercular inner wall length: 42.2 (44.6) 47 lm; number of specimens: 2.
Comparison. Typical forms of Canningia diastatikos most resemble Canningia grandis which has a similar ectophragmal reticulum. However, Canningia diastatikos differs in that extensive ectophragm relief and separation are restricted to the ambital margins; in addition, there is typically greater separation between the autophragm and ectophragm in Canningia diastatikos. Canningia bassensis also has separation of wall layers restricted to the ambital margins, but has an ectophragm that occurs in elevated patches resulting in a clearly discernable cingulum indicated by transverse sutural folds. Rare specimens of Canningia diastatikos with closely appressed wall layers (Plate 3, figures 4–6) bear low-relief ornamentation similar to that of Canningia reticulata. Canningia diastatikos exhib- its greater development and projection of the lateral and antapical horns than any other species belonging to the genus.
Derivation of name. From the Latin diastatikos, meaning disjunct or separate, in reference to the disparity in ornamentation and ectocoel separation between lateral and medial regions.
Occurrence. Canningia diastatikos is present in the assemblages from 107 to 372 m in the Northumberland Formation section exposed from Phipps Point northward to Collishaw Point. Canningia diastatikos is most abundant in the uppermost 20–30 m of the Northumberland Formation section at Collishaw Point. The only other occurrence is from a single specimen some 250 m down-section. This isolated specimen also exhibits the smallest overall dimensions recorded for the species.