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Chytroeisphaeridia mantellii
Chytroeisphaeridia? mantelli, Gitmez and Sarjeant, 1972
Now Escharisphaeridia. Originally Chytroeisphaeridia, subsequently Chytroeisphaeridia?, thirdly (and now) Escharisphaeridia.
Stover and Evitt, 1978, considered this to be a provisionally accepted species of Chytroeisphaeridia.
Holotype: Gitmez and Sarjeant, 1972, pl.1, fig.3
Locus typicus: Kimmeridge Clay, H.M. Geological Survey Borehole, Warlingham, Surrey, England
Stratum typicum: Autissiodorensis Zone, Early Kimmeridgian
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Original description: [Gitmez and Sarjeant, 1972, p. 186-187]:
Diagnosis:
Shell subspherical to elongate. The periphragm is coarsely granular and bears an irregular scatter of tubercles and of low knobs, giving it a somewhat warty appearance.
An apical archaeopyle is present, with slits extending posteriorly along presumed reflected sutures, producing a ragged appearance. The operculum most often remains attached to the ventral side of the shell.
Description:
The thick shell wall is apparently composed of two layers: the inner layer thin, the outer layer making up almost the entire wall thickness. The ornamentation of the periphragm is of three types: coarse granules, small irregularly formed lumbs (verrucae) and rounded tubercles, irregularly scattered.
A tabulation is indicated only by the slits; there is no suggestion of a cingulum.
The sulcal notch was seen only in specimens in which the operculum was completely lost, it was not perceptible in specimens with the operculum still attached. This is considered to indicate that when the operculum is present, it is attached to the ventral side of the cyst.
Dimensions:
Holotype: overall length 65 µm, breadth 60 µm.
Paratype A: overall length (apex lacking) 60 µm, breadth 65 µm. Paratype B: overall length (apex lacking) 65 µm, breadth 70 µm.
Range of Lower Kimmeridgian specimens: length (apex lacking) 25-75 µm, breadth 30-65 µm, measured specimens 12 in number.
Range of Middle Kimmeridgian specimens: length (apex lacking) 40-80 µm, breadth 50-75 µm, measured specimens 16 in number.
Range of Upper Kimmeridgian specimens: length (apex lacking) 23-70 µm, breadth 28-75 µm, measured specimens 12 in number.
According to these measurements, the species attained its largest size in the Middle Kimmeridgian.
Now Escharisphaeridia. Originally Chytroeisphaeridia, subsequently Chytroeisphaeridia?, thirdly (and now) Escharisphaeridia.
Stover and Evitt, 1978, considered this to be a provisionally accepted species of Chytroeisphaeridia.
Holotype: Gitmez and Sarjeant, 1972, pl.1, fig.3
Locus typicus: Kimmeridge Clay, H.M. Geological Survey Borehole, Warlingham, Surrey, England
Stratum typicum: Autissiodorensis Zone, Early Kimmeridgian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Gitmez and Sarjeant, 1972, p. 186-187]:
Diagnosis:
Shell subspherical to elongate. The periphragm is coarsely granular and bears an irregular scatter of tubercles and of low knobs, giving it a somewhat warty appearance.
An apical archaeopyle is present, with slits extending posteriorly along presumed reflected sutures, producing a ragged appearance. The operculum most often remains attached to the ventral side of the shell.
Description:
The thick shell wall is apparently composed of two layers: the inner layer thin, the outer layer making up almost the entire wall thickness. The ornamentation of the periphragm is of three types: coarse granules, small irregularly formed lumbs (verrucae) and rounded tubercles, irregularly scattered.
A tabulation is indicated only by the slits; there is no suggestion of a cingulum.
The sulcal notch was seen only in specimens in which the operculum was completely lost, it was not perceptible in specimens with the operculum still attached. This is considered to indicate that when the operculum is present, it is attached to the ventral side of the cyst.
Dimensions:
Holotype: overall length 65 µm, breadth 60 µm.
Paratype A: overall length (apex lacking) 60 µm, breadth 65 µm. Paratype B: overall length (apex lacking) 65 µm, breadth 70 µm.
Range of Lower Kimmeridgian specimens: length (apex lacking) 25-75 µm, breadth 30-65 µm, measured specimens 12 in number.
Range of Middle Kimmeridgian specimens: length (apex lacking) 40-80 µm, breadth 50-75 µm, measured specimens 16 in number.
Range of Upper Kimmeridgian specimens: length (apex lacking) 23-70 µm, breadth 28-75 µm, measured specimens 12 in number.
According to these measurements, the species attained its largest size in the Middle Kimmeridgian.