Back
Xenascus sarjeantii
Xenascus sarjeantii (Corradini, 1973) Stover and Evitt, 1978
Originally Phoberocysta, subsequently (and now) Xenascus.
Holotype: Corradini, 1973, pl.29, figs.2a-b
Locus typicus: Mt. Aldone, Piacenza, Italy
Stratum typicum: Senonian
Original diagnosis: Corradini, 1973, p. 181: Phoberocysta sarjeantii
Dinoflagellate cyst with elongate central body composed of smooth to lightly granular endophragm and periphragm. The two lavers, the outer of which is thinner than the inner one, are always almost completely appressed. Pericoel restricted normally to a lateral and to a well developed antapical horn.
Apical archeopyle with quadrangular margin.
Dimensions--Holotype: width of the capsule 44 µm, length (without operculum) 50 µm, width of the periphragm 85 µm, length 100 µm. Range: width of the capsule 40-(47)-52 µm, length (without operculum) 46-(53)-60 µm, width of the periphragm 65-(84)-100 µm, length 90-(103)-110 µm.
Original description: Corradini, 1973, p. 181: Phoberocysta sarjeantii
One of the two lateral horns is absent; the second being well developed and forming a wide palmate wing, normally more expanded distally than proximally.
Postcingular area fairly reduced and bearing processes with large membranous bases. Often they are connected with the antapical horn by the more or less well developed outbulge of the periphragm.
The antapical horn is always well developed in the form of a main stem bearing heterogeneous appendages, and possesses ribs and wrinkles along its entire length.
A hypothetical, reflected tabulation is pointed out by wide quadrangular, precingular plates--probably 4--and by a system of elongated cingular plates. These are delimited by thin ribs or low crests and by ?gonal processes. These processes have heterogenous shape, but normally present wide flattened bases. Archeopyle always present, being apical region unknown.
Originally Phoberocysta, subsequently (and now) Xenascus.
Holotype: Corradini, 1973, pl.29, figs.2a-b
Locus typicus: Mt. Aldone, Piacenza, Italy
Stratum typicum: Senonian
Original diagnosis: Corradini, 1973, p. 181: Phoberocysta sarjeantii
Dinoflagellate cyst with elongate central body composed of smooth to lightly granular endophragm and periphragm. The two lavers, the outer of which is thinner than the inner one, are always almost completely appressed. Pericoel restricted normally to a lateral and to a well developed antapical horn.
Apical archeopyle with quadrangular margin.
Dimensions--Holotype: width of the capsule 44 µm, length (without operculum) 50 µm, width of the periphragm 85 µm, length 100 µm. Range: width of the capsule 40-(47)-52 µm, length (without operculum) 46-(53)-60 µm, width of the periphragm 65-(84)-100 µm, length 90-(103)-110 µm.
Original description: Corradini, 1973, p. 181: Phoberocysta sarjeantii
One of the two lateral horns is absent; the second being well developed and forming a wide palmate wing, normally more expanded distally than proximally.
Postcingular area fairly reduced and bearing processes with large membranous bases. Often they are connected with the antapical horn by the more or less well developed outbulge of the periphragm.
The antapical horn is always well developed in the form of a main stem bearing heterogeneous appendages, and possesses ribs and wrinkles along its entire length.
A hypothetical, reflected tabulation is pointed out by wide quadrangular, precingular plates--probably 4--and by a system of elongated cingular plates. These are delimited by thin ribs or low crests and by ?gonal processes. These processes have heterogenous shape, but normally present wide flattened bases. Archeopyle always present, being apical region unknown.