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Sarjeantia
From Williams et al., 2017:
[Sarjeantia, Horowitz, 1975, p. 25. Emendation: Fensome and Sarjeant, 1982, p. 51-53.
Spore genus.
Tax. sr. syn.: Aratrisporites Leschik, 1956, a monolete spore, according to Conway and Cousminer (1983, p.35) and Fensome et al. (1993b, p.191). Sarjeant (1988, p.177–180) maintained that this genus represents dinoflagellates.
Type species: Sarjeantia triassica, Horowitz, 1975 (pl.1, fig.7)]
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Original description: [Horowitz, 1975]: (Translation: Stover and Evitt, 1978, p. 238):
Description:
Proximate dinoflagellate cyst. Cyst biconical, asymmetric. Hypotract hemispherical, epitract conical with a slight indication of an apical horn Epitract a little smaller than hypotract. Equatorial cingulum present; tabulation not visible, probably concealed by a dense sculpture. Miniscule spines cover the entire surface of the cyst. Spines 2-3 µm long, numerous, regularly distributed, pointed.
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Emended description:
Fensome and Sarjeant, 1982:
Diagnosis:
Proximate, circumcavate to holocavate dinoflagellate cysts. Periblast spheroidal to ovoidal or rounded-subpolygonal in shape, with or without an apical horn or mamelon; endoblast similarly variable in shape and again with or without an apical horn or mamelon. The periphragm is densely covered with short spines, less that 1/10 of the shortest cyst cross-measurement in length and of variable form.
Cingulum indicated with variable clarity: Other features of paratabulation indicated faintly or not at all.
Archaeopyle single-plate precingular (type P).
Affinities:
Sarjeantia differs from Scriniodinium in its dense cover of periphragmal spines and from many species of that genus in its lack of parasutural crests. It differs from Scriniocassis in its lack of a reticulum between the wall layers and in its spine cover; and from Thalassiphora in its shape and spine cover.
[Sarjeantia, Horowitz, 1975, p. 25. Emendation: Fensome and Sarjeant, 1982, p. 51-53.
Spore genus.
Tax. sr. syn.: Aratrisporites Leschik, 1956, a monolete spore, according to Conway and Cousminer (1983, p.35) and Fensome et al. (1993b, p.191). Sarjeant (1988, p.177–180) maintained that this genus represents dinoflagellates.
Type species: Sarjeantia triassica, Horowitz, 1975 (pl.1, fig.7)]
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Original description: [Horowitz, 1975]: (Translation: Stover and Evitt, 1978, p. 238):
Description:
Proximate dinoflagellate cyst. Cyst biconical, asymmetric. Hypotract hemispherical, epitract conical with a slight indication of an apical horn Epitract a little smaller than hypotract. Equatorial cingulum present; tabulation not visible, probably concealed by a dense sculpture. Miniscule spines cover the entire surface of the cyst. Spines 2-3 µm long, numerous, regularly distributed, pointed.
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Emended description:
Fensome and Sarjeant, 1982:
Diagnosis:
Proximate, circumcavate to holocavate dinoflagellate cysts. Periblast spheroidal to ovoidal or rounded-subpolygonal in shape, with or without an apical horn or mamelon; endoblast similarly variable in shape and again with or without an apical horn or mamelon. The periphragm is densely covered with short spines, less that 1/10 of the shortest cyst cross-measurement in length and of variable form.
Cingulum indicated with variable clarity: Other features of paratabulation indicated faintly or not at all.
Archaeopyle single-plate precingular (type P).
Affinities:
Sarjeantia differs from Scriniodinium in its dense cover of periphragmal spines and from many species of that genus in its lack of parasutural crests. It differs from Scriniocassis in its lack of a reticulum between the wall layers and in its spine cover; and from Thalassiphora in its shape and spine cover.