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Canninginopsis ordospinosa
Canninginopsis ordospinosa, Smith, 1992
Holotype: Smith, 1992, fig.51
Locus typicus: Cape Lamb, Vega Island, James Ross Island Area, Antarctica
Stratum typicum: Late Campanian-Early Maastrichtian
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Original description: [Smith, 1992, p. 342]:
Diagnosis:
A species of Canninginopsis which has two antapical, one postcingular, and one apical horn. The cyst surface bears variably developed granulate surface sculpture and pandasutural rows of spines.
Description:
Acavate cyst, often showing development of two antapical, one postcingular, and one apical horn.
The autophragm is thin (<0.5 µm) and bears an ornament of intratabular grana and two to three pandasutural rows of spines and/or grana. These spines are up to 6 µm in length and may furcate at their distal extremities. The spines present at the tips of the horns are always the largest and most elaborate in form.
The reflected paratabulation is variably developed and is rarely fully present on any specimen, when present it is always best developed on the dorsal surface. The paratabulation formula is 4", 6"", 5""", 1p, 1"""", Xs, Xc.
The archaeopyle is apical, type (tA), and the operculum is free.
The horns are between 5-15 µm in length. The left antapical horn is always larger than the right, and the right postcingular horn is variably developed from a small bulge to a prominent horn. The length of the apical horn is also variable.
Dimensions (µm): Min Mean Max
Overall length: 97101108
Overall breadth: 6684100
Length without operculum: 557285
Specimens measured: 12
Affinities:
Canninginopsis ordospinosa differs from all others of the genus in having a postcingular horn and a distinctive spinose pandasutural ornament. The spines, when well developed, are similar to the spines found on Pseudoceratium securigerum. Canninginopsis ordospinosa can be distinguished from C. bretonica by the development of a postcingular horn, a positive surface relief of grana, and pandasutural rows of spines which are often furcate at their distal extremities. Canninginopsis bretonica has a finely foveolate negative surface sculpture, more readily discernible perforate parasutural septa or denticulate ridges (due to damaged distal margin of septa) with only the occasional occurrence of two rows of penitabular septa. Canninginopsis ordospinosa has been recorded in sediments from James Ross and Vega islands (Askin 1988) and Cockburn Island (Askin et all. 1991).
Holotype: Smith, 1992, fig.51
Locus typicus: Cape Lamb, Vega Island, James Ross Island Area, Antarctica
Stratum typicum: Late Campanian-Early Maastrichtian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Smith, 1992, p. 342]:
Diagnosis:
A species of Canninginopsis which has two antapical, one postcingular, and one apical horn. The cyst surface bears variably developed granulate surface sculpture and pandasutural rows of spines.
Description:
Acavate cyst, often showing development of two antapical, one postcingular, and one apical horn.
The autophragm is thin (<0.5 µm) and bears an ornament of intratabular grana and two to three pandasutural rows of spines and/or grana. These spines are up to 6 µm in length and may furcate at their distal extremities. The spines present at the tips of the horns are always the largest and most elaborate in form.
The reflected paratabulation is variably developed and is rarely fully present on any specimen, when present it is always best developed on the dorsal surface. The paratabulation formula is 4", 6"", 5""", 1p, 1"""", Xs, Xc.
The archaeopyle is apical, type (tA), and the operculum is free.
The horns are between 5-15 µm in length. The left antapical horn is always larger than the right, and the right postcingular horn is variably developed from a small bulge to a prominent horn. The length of the apical horn is also variable.
Dimensions (µm): Min Mean Max
Overall length: 97101108
Overall breadth: 6684100
Length without operculum: 557285
Specimens measured: 12
Affinities:
Canninginopsis ordospinosa differs from all others of the genus in having a postcingular horn and a distinctive spinose pandasutural ornament. The spines, when well developed, are similar to the spines found on Pseudoceratium securigerum. Canninginopsis ordospinosa can be distinguished from C. bretonica by the development of a postcingular horn, a positive surface relief of grana, and pandasutural rows of spines which are often furcate at their distal extremities. Canninginopsis bretonica has a finely foveolate negative surface sculpture, more readily discernible perforate parasutural septa or denticulate ridges (due to damaged distal margin of septa) with only the occasional occurrence of two rows of penitabular septa. Canninginopsis ordospinosa has been recorded in sediments from James Ross and Vega islands (Askin 1988) and Cockburn Island (Askin et all. 1991).