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Gonyaulacysta jurassica ssp. brevis
Gonyaulacysta jurassica subsp. brevis" (Johnson and Hills, 1973, p.206, pl.1, figs.11,14) Lentin and Williams, 1975, p.2151.
Originally Gonyaulacysta jurassica var. brevis, subsequently Gonyaulacysta jurassica subsp. brevis.
Taxonomic senior synonym: Gonyaulax (now Gonyaulacysta) jurassica subsp. adecta var. longicornis, according to Sarjeant (1982b, p.31).
Holotype: Johnson and Hills, 1973, pl.1, fig.14.
Age: ?Late Callovian-Early Oxfordian
Original description (Johnson and Hills, 1973)
Description: Cysts of G. jurassica which have cingulums displaced toward the antapex, thus reducing the length of the hypotract to less than 1/4 the over-all length of the cyst. The epitract is uniformly conical whereas the hypotract has the form of a broad, shallow concavity ; sutures are marked by low ridges.
Dimensions : (20 specimens) Over-all length 64-74 µm,, width 38-69 µm.
Holotype : 71P-1-2-3 2/5 114/40 . 2
Distribution: ? Upper Callovian - Lower Oxfordian, Axel Heiberg and Ellesmere islands.
Remarks : Cysts of this type occur in association with those of G. jurassica in the lower part of the range of the species. Near the top of their range these cysts, like those of G. jurassica, show a tendency to develop an elongate apical horn . The rule followed here (after Sarjeant, 1961) has been to refer all cysts of G. jurassica that have apical horns exceeding 1/3 of the cyst length to G.jurassica var. longicorn is.
Originally Gonyaulacysta jurassica var. brevis, subsequently Gonyaulacysta jurassica subsp. brevis.
Taxonomic senior synonym: Gonyaulax (now Gonyaulacysta) jurassica subsp. adecta var. longicornis, according to Sarjeant (1982b, p.31).
Holotype: Johnson and Hills, 1973, pl.1, fig.14.
Age: ?Late Callovian-Early Oxfordian
Original description (Johnson and Hills, 1973)
Description: Cysts of G. jurassica which have cingulums displaced toward the antapex, thus reducing the length of the hypotract to less than 1/4 the over-all length of the cyst. The epitract is uniformly conical whereas the hypotract has the form of a broad, shallow concavity ; sutures are marked by low ridges.
Dimensions : (20 specimens) Over-all length 64-74 µm,, width 38-69 µm.
Holotype : 71P-1-2-3 2/5 114/40 . 2
Distribution: ? Upper Callovian - Lower Oxfordian, Axel Heiberg and Ellesmere islands.
Remarks : Cysts of this type occur in association with those of G. jurassica in the lower part of the range of the species. Near the top of their range these cysts, like those of G. jurassica, show a tendency to develop an elongate apical horn . The rule followed here (after Sarjeant, 1961) has been to refer all cysts of G. jurassica that have apical horns exceeding 1/3 of the cyst length to G.jurassica var. longicorn is.