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Canningia wilsonii
Canningia wilsonii, Slimani, H. et al., 2021
Holotype: Sample KBL13, slide 1, England Finder (EF) coordinates S44/4 (Fig. 3, Plate IA–E); Slimani, H. et al. 2021
Stratigraphic range: Morocco - upper Campanian - Sekada, Tattofte and Bou Lila section; as Senoniasphaera reticulata: Santonian, lower and upper Campanian, lowermost Maastrichtian
Age: upper Campanian
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Original description: [Slimani, H. et al. 2021]:
Diagnosis:
Lenticular cyst of Canningia characterized by a finely to coarsely reticulate ectophragm supported by numerous fine, solid pillars.
The ectophragm is finely reticulate and very close to the endophragm on the mid-dorsal surface, becoming coarsely reticulate and more distant around the periphery, but always absent from the ventral surface.
Archeopyle apical of type (tA) and operculum usually free.
Tabulation indicated on the dorsal surface mostly by low sutural crests and by principal and accessory archeopyle sutures.
Description:
The cyst is generally large, proximate, bi-layered, pentagonal to subpentagonal in dorsoventral view, with an apical lobation and 2 antapical horns, whose the right one is reduced to absent and the left one is the largest (5–10 μm length). The lateral margins of the cyst are convex and generally without pronounced protrusions at the cingulum. The cyst is often preserved in the dorsoventral position.
Cyst wall: consists of a smooth to slightly granulate endophragm (~ 1 μm thick), giving rise to equidistantly spaced numerous fine and solid pillars. The latter are densely packed, but short (1.5–3 μm length) in the mid-dorsal and mid-ventral surfaces, becoming longer and longer (up to 20 μm high) towards the margins and support a reticulate ectophragm (Plate IA–D).
Ectophragm: finely reticulate (0.5–2 μm diameter) and very close to the endoocyst on the mid-dorsal surface, becoming more coarsely reticulate (up to 5 μm diameter) and more distant around the periphery, but is always absent in the ventral surface. The pillars and the reticulated ectophragm together show at first glance a fibro-reticulate appearance of the cyst and it is not always easy to observe clearly the pillars since they may be partially obscured by the reticulate ectophragm.
The ventrodorsal outline of the endocyst is similar to that of the ectocyst. The width of the ectocoel is always very narrow in the area between the antapical horns, where the ectophragm is very close to the endophragm and may be largest at the apical and antapical horns, but with regular wide elsewhere in the margin area.
Tabulation: indicated by low and fine sutural crests associated with penitabular coarser reticulum of the ectophragm on the dorsal surface and also by principal and accessory archeopyle sutures (Fig. 3, Plate IA–D). The ventral area is untabulated. We recognized 4 apical, 6 precingular, 4 cingular, 3 postcingular interpreted as 3′′′, 4′′′ and 5′′′ and 1 antapical plates.
Archeopyle: apical, type (tA), having principal archeopyle suture zigzag with offset sulcal notch and usually free operculum (Fig. 3, Plate IA).
Dimensions:
Range for 10 specimens measured: overall length without operculum 72(79)90 μm, overall width 73(88)100 μm, central body length 60(65)78 μm, central body width 65(73)85 μm
Holotype: overall length without operculum 80 μm, overall width 95 μm, central body length 65 μm, central body width 75 μm.
Remarks:
Canningia wilsonii sp. nov. is conspecific with Senoniasphaera reticulata described informally by Wilson (1974) and with species recognized (as Senoniasphaera reticulata in Wilson (1974) by Masure (1983, 1985), Foucher (1985), Louwye (1991), Slimani (1995, 2000, 2001a), and (as Canningia sp. 1) by Aleksandrova and Zaporozhets (2008). The new species is here assigned to the genus Canningia, following the emendation of this genus and its type species Canningia reticulata by Helby (1987, p. 321–323). According to the latter author, Canningia is holocavate and differs from Senoniasphaera Clarke and Verdier, 1967 by the circumcavate cyst with a distinctive pericoel of the latter, although some periphragm supports have been reported.
Affinities:
Canningia wilsonii sp. nov. differs from the other species of the genus Canningia, mainly by its densely packed pillars between the wall layers, its ectophragm finely reticulate, on the mid-dorsal surface, to coarsely reticulate elsewhere. Canningia reticulata (Cookson and Eisenack, 1960b), emend. Helby, 1987 resembles Canningia wilsonii sp. nov. by its densely packed ectophragm supports and its reticulate ectophragm, but differs from the latter in having a more delicate and very finely reticulate to rugoreticulate rather than finely (on mid-dorsal surface) to coarsely (elsewhere) reticulate ectophragm and a much more narrower ectocoel. The ectophragm in C. reticulata is generally more closely appressed to the endophragm over most of the cyst, having indication of tabulation on dorsal and also ventral surfaces, while in Canningia wilsonii sp. nov. the ectophragm is absent from the ventral surface and the indication of tabulation is present only on the dorsal surface.
Canningia grandis Helby, 1987 is distinguished from Canningia wilsonii sp. nov. in being larger and in having thicker and spaced processes supporting a robust reticulum over most of the cyst.
Canningia bassensis Marshall, 1990a resembles Canningia wilsonii in being holocavate, but differs from the latter by its larger size and its fenestrate ectophragm, covering the endocyst on the dorsal and also the ventral surfaces.
Canninginopsis bretonica Marshall, 1990b differs from the new species in having a single layer. Senoniasphaera macroreticulata Prince et al., 2008 has a reticulate periphragm, but differs from the new species in being circumcavate.
Holotype: Sample KBL13, slide 1, England Finder (EF) coordinates S44/4 (Fig. 3, Plate IA–E); Slimani, H. et al. 2021
Stratigraphic range: Morocco - upper Campanian - Sekada, Tattofte and Bou Lila section; as Senoniasphaera reticulata: Santonian, lower and upper Campanian, lowermost Maastrichtian
Age: upper Campanian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Slimani, H. et al. 2021]:
Diagnosis:
Lenticular cyst of Canningia characterized by a finely to coarsely reticulate ectophragm supported by numerous fine, solid pillars.
The ectophragm is finely reticulate and very close to the endophragm on the mid-dorsal surface, becoming coarsely reticulate and more distant around the periphery, but always absent from the ventral surface.
Archeopyle apical of type (tA) and operculum usually free.
Tabulation indicated on the dorsal surface mostly by low sutural crests and by principal and accessory archeopyle sutures.
Description:
The cyst is generally large, proximate, bi-layered, pentagonal to subpentagonal in dorsoventral view, with an apical lobation and 2 antapical horns, whose the right one is reduced to absent and the left one is the largest (5–10 μm length). The lateral margins of the cyst are convex and generally without pronounced protrusions at the cingulum. The cyst is often preserved in the dorsoventral position.
Cyst wall: consists of a smooth to slightly granulate endophragm (~ 1 μm thick), giving rise to equidistantly spaced numerous fine and solid pillars. The latter are densely packed, but short (1.5–3 μm length) in the mid-dorsal and mid-ventral surfaces, becoming longer and longer (up to 20 μm high) towards the margins and support a reticulate ectophragm (Plate IA–D).
Ectophragm: finely reticulate (0.5–2 μm diameter) and very close to the endoocyst on the mid-dorsal surface, becoming more coarsely reticulate (up to 5 μm diameter) and more distant around the periphery, but is always absent in the ventral surface. The pillars and the reticulated ectophragm together show at first glance a fibro-reticulate appearance of the cyst and it is not always easy to observe clearly the pillars since they may be partially obscured by the reticulate ectophragm.
The ventrodorsal outline of the endocyst is similar to that of the ectocyst. The width of the ectocoel is always very narrow in the area between the antapical horns, where the ectophragm is very close to the endophragm and may be largest at the apical and antapical horns, but with regular wide elsewhere in the margin area.
Tabulation: indicated by low and fine sutural crests associated with penitabular coarser reticulum of the ectophragm on the dorsal surface and also by principal and accessory archeopyle sutures (Fig. 3, Plate IA–D). The ventral area is untabulated. We recognized 4 apical, 6 precingular, 4 cingular, 3 postcingular interpreted as 3′′′, 4′′′ and 5′′′ and 1 antapical plates.
Archeopyle: apical, type (tA), having principal archeopyle suture zigzag with offset sulcal notch and usually free operculum (Fig. 3, Plate IA).
Dimensions:
Range for 10 specimens measured: overall length without operculum 72(79)90 μm, overall width 73(88)100 μm, central body length 60(65)78 μm, central body width 65(73)85 μm
Holotype: overall length without operculum 80 μm, overall width 95 μm, central body length 65 μm, central body width 75 μm.
Remarks:
Canningia wilsonii sp. nov. is conspecific with Senoniasphaera reticulata described informally by Wilson (1974) and with species recognized (as Senoniasphaera reticulata in Wilson (1974) by Masure (1983, 1985), Foucher (1985), Louwye (1991), Slimani (1995, 2000, 2001a), and (as Canningia sp. 1) by Aleksandrova and Zaporozhets (2008). The new species is here assigned to the genus Canningia, following the emendation of this genus and its type species Canningia reticulata by Helby (1987, p. 321–323). According to the latter author, Canningia is holocavate and differs from Senoniasphaera Clarke and Verdier, 1967 by the circumcavate cyst with a distinctive pericoel of the latter, although some periphragm supports have been reported.
Affinities:
Canningia wilsonii sp. nov. differs from the other species of the genus Canningia, mainly by its densely packed pillars between the wall layers, its ectophragm finely reticulate, on the mid-dorsal surface, to coarsely reticulate elsewhere. Canningia reticulata (Cookson and Eisenack, 1960b), emend. Helby, 1987 resembles Canningia wilsonii sp. nov. by its densely packed ectophragm supports and its reticulate ectophragm, but differs from the latter in having a more delicate and very finely reticulate to rugoreticulate rather than finely (on mid-dorsal surface) to coarsely (elsewhere) reticulate ectophragm and a much more narrower ectocoel. The ectophragm in C. reticulata is generally more closely appressed to the endophragm over most of the cyst, having indication of tabulation on dorsal and also ventral surfaces, while in Canningia wilsonii sp. nov. the ectophragm is absent from the ventral surface and the indication of tabulation is present only on the dorsal surface.
Canningia grandis Helby, 1987 is distinguished from Canningia wilsonii sp. nov. in being larger and in having thicker and spaced processes supporting a robust reticulum over most of the cyst.
Canningia bassensis Marshall, 1990a resembles Canningia wilsonii in being holocavate, but differs from the latter by its larger size and its fenestrate ectophragm, covering the endocyst on the dorsal and also the ventral surfaces.
Canninginopsis bretonica Marshall, 1990b differs from the new species in having a single layer. Senoniasphaera macroreticulata Prince et al., 2008 has a reticulate periphragm, but differs from the new species in being circumcavate.