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Histiocysta variornata
From Fensome et al., 2019:
Histiocysta ?variornata Slimani, 1994, p.18–19, pl.2, figs.19–20,24–33. Holotype: Slimani, 1994, pl.2, figs.19–20,30–33. Questionable assignment: Slimani (1994, p.18). Taxonomic junior synonym: Chlamydophorella inconscripta (name not validly published), according to Slimani (2001a, p.192). Age: late Campanian–early Maastrichtian.
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Original description (translation PKB 2025)
Name derivation: Latin: varius, varied, ornatus, decorated; referring to the variable ornamentation of the cyst.
Holotype: Turnhout -864.60 m, preparation 7, coord. E.F. I41/4
Type locality: Turnhout -864.60 m
Type horizon: Lower Maastrichtian
Synonymy: ?1974: Chlamydophorella inconscripta in Wilson, p. 207, pl. 22, figs. 11-13, text-fig. 34.
Diagnosis: Small, strongly ellipsoidal proximal cyst with an epicyst slightly smaller than the hypocyst. It bears an extremely variable ornamentation which supports a thin and fragile periphragm. The paratabulation is of the gonyaulacoid type indicated by parasutural ridges which are low, irregular and often interrupted in the paracingulate region, and corresponds to the following formula: 1 pr, 4', 4a, 6", 6c, 6:"', 1p, 1"". The archaeopyle is apical and intercalary of type (tAtI)a with a typically adnate operculum vertically.
Dimensions:
Holotype: Length: 38 µm, Width: 26 µm
Variation: Length: 36-42 µm, Width: 24-28 µm
Number of specimens measured: 18
Material: >60 specimens.
Description: The endophragm (1 to 2 µm thick) is smooth to slightly scabrous; the highly variable intratabular ornamentation is formed by solid processes, slightly flared distally, solitary or irregularly connected proximally, and by vermicules and ridges that may combine to form an imperfect reticulum. The shape, distribution, and density of these ornaments vary intraspecifically. The parasutural ridges are low (2 to 3 µm high in the holotype), more or less continuous in the epicystal and hypocystal regions, and distorted by the intratabular ridges and vermicules, while the paracingulate ridges are very discontinuous. The arrangement of the hypocystal paraplates is partiform. The paracingulate follows a circular to slightly aevorotatory course. The posterior sulcal portion is subomegaform. The operculum is small (14 µm in the holotype) and suboval in outline with an angular margin; it is composed of 4 apical paraplates, 4 intercalary, and 1 preapical.
Note:
Histiocysta variornata sp. nov. is characterized by its ellipsoidal shape and variable intratabular ornamentation. It is provisionally assigned to the genus Histiocysta, primarily because it has a periphragm that covers the parasutural ridges and intratabular ornamentation. The type of its archaeopyle is reminiscent of Microdinium, but its morphological characteristics are those of Histiocysta.
Comparison: Chlamydophorella inconscripta (lower Maastrichtian, Denmark), described by Wilson in his unpublished 1974 Ph.D. work, apparently shares the same characteristics as Histiocysta variornata sp. nov., except that its paratabulation is very vague. Cassiculosphaeridia ovalis HARKER, T. SARJEANT, and L. CADWEL (1990: pp. 87-88, pl. 2, figs. 7-8, 11-12, text-fig. 19), found in the Campanian of the Interior Plains of Canada, resembles the studied species in size, shape, and morphological characteristics, but a membrane covering the ornamentation was not reported in its original description, and its archaeopyle is defined as apical. Stratigraphic distribution:
Turnhout: -933 to -836.95 m, Upper Campanian - Lower Maastrichtian
Histiocysta ?variornata Slimani, 1994, p.18–19, pl.2, figs.19–20,24–33. Holotype: Slimani, 1994, pl.2, figs.19–20,30–33. Questionable assignment: Slimani (1994, p.18). Taxonomic junior synonym: Chlamydophorella inconscripta (name not validly published), according to Slimani (2001a, p.192). Age: late Campanian–early Maastrichtian.
---------------------------------------------------------------------------------------------------
Original description (translation PKB 2025)
Name derivation: Latin: varius, varied, ornatus, decorated; referring to the variable ornamentation of the cyst.
Holotype: Turnhout -864.60 m, preparation 7, coord. E.F. I41/4
Type locality: Turnhout -864.60 m
Type horizon: Lower Maastrichtian
Synonymy: ?1974: Chlamydophorella inconscripta in Wilson, p. 207, pl. 22, figs. 11-13, text-fig. 34.
Diagnosis: Small, strongly ellipsoidal proximal cyst with an epicyst slightly smaller than the hypocyst. It bears an extremely variable ornamentation which supports a thin and fragile periphragm. The paratabulation is of the gonyaulacoid type indicated by parasutural ridges which are low, irregular and often interrupted in the paracingulate region, and corresponds to the following formula: 1 pr, 4', 4a, 6", 6c, 6:"', 1p, 1"". The archaeopyle is apical and intercalary of type (tAtI)a with a typically adnate operculum vertically.
Dimensions:
Holotype: Length: 38 µm, Width: 26 µm
Variation: Length: 36-42 µm, Width: 24-28 µm
Number of specimens measured: 18
Material: >60 specimens.
Description: The endophragm (1 to 2 µm thick) is smooth to slightly scabrous; the highly variable intratabular ornamentation is formed by solid processes, slightly flared distally, solitary or irregularly connected proximally, and by vermicules and ridges that may combine to form an imperfect reticulum. The shape, distribution, and density of these ornaments vary intraspecifically. The parasutural ridges are low (2 to 3 µm high in the holotype), more or less continuous in the epicystal and hypocystal regions, and distorted by the intratabular ridges and vermicules, while the paracingulate ridges are very discontinuous. The arrangement of the hypocystal paraplates is partiform. The paracingulate follows a circular to slightly aevorotatory course. The posterior sulcal portion is subomegaform. The operculum is small (14 µm in the holotype) and suboval in outline with an angular margin; it is composed of 4 apical paraplates, 4 intercalary, and 1 preapical.
Note:
Histiocysta variornata sp. nov. is characterized by its ellipsoidal shape and variable intratabular ornamentation. It is provisionally assigned to the genus Histiocysta, primarily because it has a periphragm that covers the parasutural ridges and intratabular ornamentation. The type of its archaeopyle is reminiscent of Microdinium, but its morphological characteristics are those of Histiocysta.
Comparison: Chlamydophorella inconscripta (lower Maastrichtian, Denmark), described by Wilson in his unpublished 1974 Ph.D. work, apparently shares the same characteristics as Histiocysta variornata sp. nov., except that its paratabulation is very vague. Cassiculosphaeridia ovalis HARKER, T. SARJEANT, and L. CADWEL (1990: pp. 87-88, pl. 2, figs. 7-8, 11-12, text-fig. 19), found in the Campanian of the Interior Plains of Canada, resembles the studied species in size, shape, and morphological characteristics, but a membrane covering the ornamentation was not reported in its original description, and its archaeopyle is defined as apical. Stratigraphic distribution:
Turnhout: -933 to -836.95 m, Upper Campanian - Lower Maastrichtian