Back
Canningia crassimura
Canningia crassimura Vieira and Mahdi, 2021, p. 3-5
Holotype: Plate 1, figure 1, Vieira and Mahdi, 2021
Type locality: Møre Basin (Norway)
Stratigraphic extent: Late Cretaceous, middle-late Campanian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Vieira and Mahdi, 2021, p. 3-5]:
Diagnosis:
Proximate, circular to subspherical dinoflagellate cyst. Tabulation is not represented, with the exception of the cingulum. The antapical end is usually rounded and occasionally bears blunt lobation. The endophragm is very thick, up to 4 µm.
Description:
Proximate, rounded to subcircular dinoflagellate cyst of intermediate size; length and breadth of cyst are almost equal; occasionally the width exceeds the length.
Central body is dorso-ventrally compressed.
The periphragm is thin and hyaline, scabrate/punctate to minutely microreticulate.
The endophragm is relatively thick, up to 4 µm.
Cingulum often presents with two rounded, slightly indented protrusions at the cingulum area.
The archaeopyle is apical Type tA with an angular suture line indicating six precingular plates.
The operculum sometimes remains attached with a small distinct bulge or nipple-like protrusion up to 8 µm in height and 9 µm in width.
Antapex is rounded or occasionally with one faint, left lobe.
Dimensions:
Central body length 47 (59) 68 µm, length with operculum attached 57 (69) 76 µm, width 66 (76) 87 µm.
20 specimens measured
Affinities/Comparison:
Canningia keiemensis, described by Louwye 1997 (latest Cenomanian–Santonian) also exhibits a relatively thick endophragm (approximately 2 µm), although this species differs from Canningia crassimura sp. nov. by the presence of solid pillar-like protrusions covering the endophragm; also the periphragm displays two distinct rounded protrusions at the cingulum and a left antapical protrusion. Canningia bassensis was described by Marshall 1990 (Campanian) from the Pisces-1 well, south-eastern Australia, as holocavate and has an endophragm that covers the cyst completely, and is also characterised by the numerous fine pillars extending between the periphragm and endophragm. Canningia diastatikos, described by McLachlan et al. (2019), is similar to C. bassensis in having a separation of wall layers, but the endophragm does not occur in elevated patches. The distinct thickening of the endophragm is the main feature that differentiates this new species from other species within the genus.
Holotype: Plate 1, figure 1, Vieira and Mahdi, 2021
Type locality: Møre Basin (Norway)
Stratigraphic extent: Late Cretaceous, middle-late Campanian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Vieira and Mahdi, 2021, p. 3-5]:
Diagnosis:
Proximate, circular to subspherical dinoflagellate cyst. Tabulation is not represented, with the exception of the cingulum. The antapical end is usually rounded and occasionally bears blunt lobation. The endophragm is very thick, up to 4 µm.
Description:
Proximate, rounded to subcircular dinoflagellate cyst of intermediate size; length and breadth of cyst are almost equal; occasionally the width exceeds the length.
Central body is dorso-ventrally compressed.
The periphragm is thin and hyaline, scabrate/punctate to minutely microreticulate.
The endophragm is relatively thick, up to 4 µm.
Cingulum often presents with two rounded, slightly indented protrusions at the cingulum area.
The archaeopyle is apical Type tA with an angular suture line indicating six precingular plates.
The operculum sometimes remains attached with a small distinct bulge or nipple-like protrusion up to 8 µm in height and 9 µm in width.
Antapex is rounded or occasionally with one faint, left lobe.
Dimensions:
Central body length 47 (59) 68 µm, length with operculum attached 57 (69) 76 µm, width 66 (76) 87 µm.
20 specimens measured
Affinities/Comparison:
Canningia keiemensis, described by Louwye 1997 (latest Cenomanian–Santonian) also exhibits a relatively thick endophragm (approximately 2 µm), although this species differs from Canningia crassimura sp. nov. by the presence of solid pillar-like protrusions covering the endophragm; also the periphragm displays two distinct rounded protrusions at the cingulum and a left antapical protrusion. Canningia bassensis was described by Marshall 1990 (Campanian) from the Pisces-1 well, south-eastern Australia, as holocavate and has an endophragm that covers the cyst completely, and is also characterised by the numerous fine pillars extending between the periphragm and endophragm. Canningia diastatikos, described by McLachlan et al. (2019), is similar to C. bassensis in having a separation of wall layers, but the endophragm does not occur in elevated patches. The distinct thickening of the endophragm is the main feature that differentiates this new species from other species within the genus.