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Sentusidinium hexagonale
Sentusidinium hexagonale Kumar, 1986
Taxonomic senior synonym: Sentusidinium sparsibarbatum, according to Courtinat in Fauconnier and Masure (2004, p.486). Courtinat in Fauconnier and Masure (2004, p.487) simultaneously considered this to be a problematic species of Sentusidinium.
Holotype: Kumar, 1986, pl.1, fig.5
Locus typicus: Kachchh, India
Stratum typicum: Kimmeridgian-Tithonian
Original diagnosis: Kumar, 1986, p.400
Proximate to proximochorate, sphaerical or subsphaerical cyst with an apical archaeopyle. Archaeopyle opening typically hexagonal, operculum free. Autophragm thick and densely covered by nontabular, hairlike processes.
Original description: Kumar, 1986, p.401
These are proximate to proximochorate cysts, sphaerical to subsphaerical in shape. They show a circular to oval or ovoidal outline if viewed from the apical or antapical ends. Paratabulation features are essentially lacking except for the presence of an apical archaeopyle. The archaeopyle opening is typically hexagonal and only sometimes it might show accessory archaeopyle parasutures indicating the presence of six precingular paraplates and thus showing its affinity to the gonyaulacacean group. The operculum is free. Wall single layered. The autophragm is thick and densely covered by uniformly distributed, nontabular, hairlike processes, which are sometimes bifid. The autophragm surface is scabrate.
Dimension: Based on ten specimens. Diameter of cyst = 24-36µm. Length of processes = 1.5-2.5µm.
Affinities:
Kumar, 1986, p.401: S. hexagonalis differs from all other species of the genus Sentusidinium in having a characteristic hexagonal archaeopyle.
Taxonomic senior synonym: Sentusidinium sparsibarbatum, according to Courtinat in Fauconnier and Masure (2004, p.486). Courtinat in Fauconnier and Masure (2004, p.487) simultaneously considered this to be a problematic species of Sentusidinium.
Holotype: Kumar, 1986, pl.1, fig.5
Locus typicus: Kachchh, India
Stratum typicum: Kimmeridgian-Tithonian
Original diagnosis: Kumar, 1986, p.400
Proximate to proximochorate, sphaerical or subsphaerical cyst with an apical archaeopyle. Archaeopyle opening typically hexagonal, operculum free. Autophragm thick and densely covered by nontabular, hairlike processes.
Original description: Kumar, 1986, p.401
These are proximate to proximochorate cysts, sphaerical to subsphaerical in shape. They show a circular to oval or ovoidal outline if viewed from the apical or antapical ends. Paratabulation features are essentially lacking except for the presence of an apical archaeopyle. The archaeopyle opening is typically hexagonal and only sometimes it might show accessory archaeopyle parasutures indicating the presence of six precingular paraplates and thus showing its affinity to the gonyaulacacean group. The operculum is free. Wall single layered. The autophragm is thick and densely covered by uniformly distributed, nontabular, hairlike processes, which are sometimes bifid. The autophragm surface is scabrate.
Dimension: Based on ten specimens. Diameter of cyst = 24-36µm. Length of processes = 1.5-2.5µm.
Affinities:
Kumar, 1986, p.401: S. hexagonalis differs from all other species of the genus Sentusidinium in having a characteristic hexagonal archaeopyle.