Back
Cassiculosphaeridia tunicata
Cassiculosphaeridia tunicata, Harding, 1990 ex Harding in Williams et al. 1998, p.97.
Name not validly published since lodgement of holotype not specified
Holotype: Harding, 1990, pl. 27, figs.9,11
Locus typicus: O. Gott, Lower Saxony, Germany
Stratum typicum: Late Hauterivian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Harding, 1990, p. 49-50]:
Diagnosis:
Shape: Ambitus subcircular to slightly oblate. Greatest width posterior to archaeopyle margin (paracingulum). Epicyst and hypocyst difficult to distinguish. Moderate to strong dorso-ventral compression.
Phragma: The autophragm is up to 1 µm thick with a laevigate surface texture. The distal surface of the autophragm bears an uneven reticulum of solid muri/septa (up to 2.5 µm wide and 1-2 µm high) which are nontabular in arrangement. The reticulation is variable, the lumina range from 3-18 µm in diameter. The ectophragm (0.1 µm thick) forms a continuous, highly perforate layer over the whole cyst surface. This layer is supported on the reticulum but subsides into the lumina and appears draped over the cyst surface. Perforations in the ectophragm are random, densely distributed and usually less than 1 µm in diameter. The ectophragm is often seen to "blister" over the lumina, this may be due to distortion caused by authigenic pyrite growing to the ectocoels.
Paratabulation: Hypocystal paratabulation unknown, but rare specimens show an angular archaeopyle margin giving the following epicystal paratabulation formula: 4", 6", + ai.
Archaeopyle: Type (tA), involving the loss of the apical paraplate series as a simple, polyplacoid operculum.
Paracingulum: Only distinguished on a few specimens which show alignment of the muri in the equatorial region.
Parasulcus: May show as an area of reduced reticulation, or may be evidenced by the parasulcal notch.
Dimensions:
Diameter (55) 48.9 (42) µm. Specimens = 10 (10).
Affinities:
A distinctive species of Cassiculosphaeridia due to the more coherent nature of the ectophragm. In most of the species of this genus that have been studied the ectophragm is a much more diaphanous layer formed of aggregations of granular material, rather than a solid lamellum. C. tazadensis Below, has an ectophragm which is either imperforate or perforated on a very small scale (Below 1981: Plate 12, Fig. 16).
Name not validly published since lodgement of holotype not specified
Holotype: Harding, 1990, pl. 27, figs.9,11
Locus typicus: O. Gott, Lower Saxony, Germany
Stratum typicum: Late Hauterivian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Harding, 1990, p. 49-50]:
Diagnosis:
Shape: Ambitus subcircular to slightly oblate. Greatest width posterior to archaeopyle margin (paracingulum). Epicyst and hypocyst difficult to distinguish. Moderate to strong dorso-ventral compression.
Phragma: The autophragm is up to 1 µm thick with a laevigate surface texture. The distal surface of the autophragm bears an uneven reticulum of solid muri/septa (up to 2.5 µm wide and 1-2 µm high) which are nontabular in arrangement. The reticulation is variable, the lumina range from 3-18 µm in diameter. The ectophragm (0.1 µm thick) forms a continuous, highly perforate layer over the whole cyst surface. This layer is supported on the reticulum but subsides into the lumina and appears draped over the cyst surface. Perforations in the ectophragm are random, densely distributed and usually less than 1 µm in diameter. The ectophragm is often seen to "blister" over the lumina, this may be due to distortion caused by authigenic pyrite growing to the ectocoels.
Paratabulation: Hypocystal paratabulation unknown, but rare specimens show an angular archaeopyle margin giving the following epicystal paratabulation formula: 4", 6", + ai.
Archaeopyle: Type (tA), involving the loss of the apical paraplate series as a simple, polyplacoid operculum.
Paracingulum: Only distinguished on a few specimens which show alignment of the muri in the equatorial region.
Parasulcus: May show as an area of reduced reticulation, or may be evidenced by the parasulcal notch.
Dimensions:
Diameter (55) 48.9 (42) µm. Specimens = 10 (10).
Affinities:
A distinctive species of Cassiculosphaeridia due to the more coherent nature of the ectophragm. In most of the species of this genus that have been studied the ectophragm is a much more diaphanous layer formed of aggregations of granular material, rather than a solid lamellum. C. tazadensis Below, has an ectophragm which is either imperforate or perforated on a very small scale (Below 1981: Plate 12, Fig. 16).