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Hystrichokolpoma gamospinum
From Fensome et al., 2019:
Hystrichokolpoma gamospinum Slimani, 1994, p.74–75, pl.11, figs.7–12. Holotype: Slimani, 1994, pl.11, figs.10–12; Fauconnier and Masure, 2004, pl.42, figs.10–11. Questionable assignment: Foucher in Fauconnier and Masure (2004, p.285). Age: late Campanian.
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Original description (not yet translated from French), Slimani, 1994
Name derivation: Greek: gamo, marriage, to fuse; Latin: spina, thorn; reference to the fused processes.
Holotype: Turnhout -933 m, preparation 2, coordinate Y34/2
Paratype: Turnhout -933 m, preparation 1, coordinate E.F. Z32-Z33.
Type locality: Turnhout -933 m.
Type horizon: Upper Campanian.
Diagnosis: Skolochorate, gonyaulacoid, and intermediate-sized cyst. The central body is subspheroidal to ellipsoidal, smooth, and bears one process per plate. The processes are smooth, hollow, and approximately two-thirds the length of the cyst diameter. The precingulate and postcingulate processes are broad, closed distally, subcuboidal to subcylindrical, occupying almost the entire surface of the paraplates, and typically fused laterally by their walls. The apical, paracingulate, and parasulcal processes are thin and buccinate. The gonyaulacoid-type paratabulation corresponds to the formula: 4', 6", 6c, 6"', 5s, 1"". The archaeopyle is apical with a hexagonal outline and a ventral sulcal notch. The operculum is free or very rarely in place.
Dimensions: Holotype: central body diameter: 32 µm, entire cyst diameter: 70 µm.
Variations: central body diameter: 30-42 µm.
Broad processes, length: 16-20 µm, width: 18-24 µm.
Thin processes, length: 18-24 µm, width: 2-8 µm.
Antapical process, length: 10-20 µm, width: 8-10 µm.
Number of specimens measured: 10.
Material: 15 specimens.
Description:
The thick endophragm (approximately 2 µm) and the thinner periphragm are smooth and joined between the processes; that is, the processes are formed by the periphragm. The paratabulation is of the gonyaulacoid type, indicated by the presence of a single process per plate. The precingulate processes and the postcingulate processes 1", 2", 3", 4", and 5" appear as compartments separated by septa; they are quadrangular to subquadrangular or slightly rounded at their base. They are closed distally by a membrane often convex outwards and bear numerous small spines of 1 to 2 µm on the margin of their distal end. The postcingulate processes 1" and 5" are a little less wide but a little longer than the others and often prominent. The apical, paracingulate, parasulcal processes, the postcingulate process, 6" and the posterior intercalary process 1P are constantly separate, thin, tubular, serrate to aculeate, closed or open distally and located in the center of the paraplates. The antapical process is bulbous or cylindrical and serrate to aculeate distally. The parasulcus is indicated by 5 processes.
Comparison:
Hystrichokolpoma gamospina sp. nov. is distinguished from all other species of the genus Hystrichokolpoma by the presence of a single process per plate and especially by its precingulate and postcingulate processes, which are broad and laterally fused. H. unispinum Williams and Downie (1966a) also has a single process per plate, but these processes all have the same shape and are all separate from each other. H. bullatum Wilson (1988) has postcingulate and precingulate processes that are almost the same shape as those of the species studied, but they are not fused together. Its paracingulate and parasulcal processes are pointed and apparently number two per plate.
Stratigraphic distribution:
Halembaye: scale 12, Upper Campanian (B. mucronata Zone). Turnhout -933 m, Upper Campanian.
Hystrichokolpoma gamospinum Slimani, 1994, p.74–75, pl.11, figs.7–12. Holotype: Slimani, 1994, pl.11, figs.10–12; Fauconnier and Masure, 2004, pl.42, figs.10–11. Questionable assignment: Foucher in Fauconnier and Masure (2004, p.285). Age: late Campanian.
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Original description (not yet translated from French), Slimani, 1994
Name derivation: Greek: gamo, marriage, to fuse; Latin: spina, thorn; reference to the fused processes.
Holotype: Turnhout -933 m, preparation 2, coordinate Y34/2
Paratype: Turnhout -933 m, preparation 1, coordinate E.F. Z32-Z33.
Type locality: Turnhout -933 m.
Type horizon: Upper Campanian.
Diagnosis: Skolochorate, gonyaulacoid, and intermediate-sized cyst. The central body is subspheroidal to ellipsoidal, smooth, and bears one process per plate. The processes are smooth, hollow, and approximately two-thirds the length of the cyst diameter. The precingulate and postcingulate processes are broad, closed distally, subcuboidal to subcylindrical, occupying almost the entire surface of the paraplates, and typically fused laterally by their walls. The apical, paracingulate, and parasulcal processes are thin and buccinate. The gonyaulacoid-type paratabulation corresponds to the formula: 4', 6", 6c, 6"', 5s, 1"". The archaeopyle is apical with a hexagonal outline and a ventral sulcal notch. The operculum is free or very rarely in place.
Dimensions: Holotype: central body diameter: 32 µm, entire cyst diameter: 70 µm.
Variations: central body diameter: 30-42 µm.
Broad processes, length: 16-20 µm, width: 18-24 µm.
Thin processes, length: 18-24 µm, width: 2-8 µm.
Antapical process, length: 10-20 µm, width: 8-10 µm.
Number of specimens measured: 10.
Material: 15 specimens.
Description:
The thick endophragm (approximately 2 µm) and the thinner periphragm are smooth and joined between the processes; that is, the processes are formed by the periphragm. The paratabulation is of the gonyaulacoid type, indicated by the presence of a single process per plate. The precingulate processes and the postcingulate processes 1", 2", 3", 4", and 5" appear as compartments separated by septa; they are quadrangular to subquadrangular or slightly rounded at their base. They are closed distally by a membrane often convex outwards and bear numerous small spines of 1 to 2 µm on the margin of their distal end. The postcingulate processes 1" and 5" are a little less wide but a little longer than the others and often prominent. The apical, paracingulate, parasulcal processes, the postcingulate process, 6" and the posterior intercalary process 1P are constantly separate, thin, tubular, serrate to aculeate, closed or open distally and located in the center of the paraplates. The antapical process is bulbous or cylindrical and serrate to aculeate distally. The parasulcus is indicated by 5 processes.
Comparison:
Hystrichokolpoma gamospina sp. nov. is distinguished from all other species of the genus Hystrichokolpoma by the presence of a single process per plate and especially by its precingulate and postcingulate processes, which are broad and laterally fused. H. unispinum Williams and Downie (1966a) also has a single process per plate, but these processes all have the same shape and are all separate from each other. H. bullatum Wilson (1988) has postcingulate and precingulate processes that are almost the same shape as those of the species studied, but they are not fused together. Its paracingulate and parasulcal processes are pointed and apparently number two per plate.
Stratigraphic distribution:
Halembaye: scale 12, Upper Campanian (B. mucronata Zone). Turnhout -933 m, Upper Campanian.