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Hystrichosphaerina crusta
Hystrichosphaerina crusta Dodekova, 1992
Holotype: Dodekova, 1992, pl.3, figs.1-3
Locus typicus: borehole R-2, Dabovan, Central N Bulgaria
Stratum typicum: Middle?-Late Kimmeridgian
Original diagnosis: Dodekova, 1992, p.43
Phragmochorate cyst with subspherical central body and penitabular processes with beaker-like form and linearly arranged cingular processes. The tabulation is with gonyaulacacean tabulation formula: 4?", 6", 5-6""", 1p, 1pv, 1"""", Xs. Cingulum formed of 6 pairs of slender processes. Archeopyle--apical, type A, operculum free with unknown structure.
Dimensions. Holotype: length of central body, without apex 65 Ám. breadth of central body 68 Ám, height of processes 15 Ám. Range: length 65-68 Ám, breadth 68-78 Ám, processes 8-15 Ám.
Original description: Dodekova, 1992, p.43
The wall is two-layered, the two layers being closely appressed at the central body. The periphragm forms the processes. Between them, it is scabrate to finely reticulate. Processes are beaker-like or tubiform, with strongly widened distal end. Their base is round or in the larger processes--with a flat side towards the cingulum. The wall is irregularly perforated (pl.III, fig.2), lacelike to fenestrate. There is a thickening of the periphragm in the base of the processes. The width of the latter is varying depending on the position of the process, in analogy to the plates in the tabulate proximate cysts. The cingulum is formed of 6 pairs of slender processes, capitate or bifurcate distally. Sulcus structure not distinct. The archeopyle is apical, wide and with zig-zag margin and accessory archeopyle sutures. Operculum is free. All specimens have an archeopyle and the structure of the operculum is not known.
I have at my disposal few specimens and cannot evaluate the intraspecific variability in H. crusta. There are differences in the height of the beaker-like processes.
Affinities:
Dodekova, 1992, p.43: The proportionally lower and not so intensively perforated process in H. crusta distinguish the species from the other species of genus Hystrichosphaerina. The new species reminds of the species of genus Amphorula but the latter show arcuate penitabular processes opened towards the cingulum. H. crusta is similar to Oligosphaeridium sp.1 Davey (1982, pl.2, figs.6,8) but the latter lack cingular processes.
Holotype: Dodekova, 1992, pl.3, figs.1-3
Locus typicus: borehole R-2, Dabovan, Central N Bulgaria
Stratum typicum: Middle?-Late Kimmeridgian
Original diagnosis: Dodekova, 1992, p.43
Phragmochorate cyst with subspherical central body and penitabular processes with beaker-like form and linearly arranged cingular processes. The tabulation is with gonyaulacacean tabulation formula: 4?", 6", 5-6""", 1p, 1pv, 1"""", Xs. Cingulum formed of 6 pairs of slender processes. Archeopyle--apical, type A, operculum free with unknown structure.
Dimensions. Holotype: length of central body, without apex 65 Ám. breadth of central body 68 Ám, height of processes 15 Ám. Range: length 65-68 Ám, breadth 68-78 Ám, processes 8-15 Ám.
Original description: Dodekova, 1992, p.43
The wall is two-layered, the two layers being closely appressed at the central body. The periphragm forms the processes. Between them, it is scabrate to finely reticulate. Processes are beaker-like or tubiform, with strongly widened distal end. Their base is round or in the larger processes--with a flat side towards the cingulum. The wall is irregularly perforated (pl.III, fig.2), lacelike to fenestrate. There is a thickening of the periphragm in the base of the processes. The width of the latter is varying depending on the position of the process, in analogy to the plates in the tabulate proximate cysts. The cingulum is formed of 6 pairs of slender processes, capitate or bifurcate distally. Sulcus structure not distinct. The archeopyle is apical, wide and with zig-zag margin and accessory archeopyle sutures. Operculum is free. All specimens have an archeopyle and the structure of the operculum is not known.
I have at my disposal few specimens and cannot evaluate the intraspecific variability in H. crusta. There are differences in the height of the beaker-like processes.
Affinities:
Dodekova, 1992, p.43: The proportionally lower and not so intensively perforated process in H. crusta distinguish the species from the other species of genus Hystrichosphaerina. The new species reminds of the species of genus Amphorula but the latter show arcuate penitabular processes opened towards the cingulum. H. crusta is similar to Oligosphaeridium sp.1 Davey (1982, pl.2, figs.6,8) but the latter lack cingular processes.