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Impagidinium scabrosum
From Fensome et al., 2019:
Impagidinium scabrosum Slimani, 1994, p.105–107, pl.17, figs.10–15; text-fig.13B. Holotype: Slimani, 1994, pl.17, figs.10–11. Age: late Campanian–earliest Maastrichtian.
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Original description (Slimani, 1994)
Diagnosis: Murochorate, aeavate cyst, generally polygonal in outline. The central body is ovoid to subspheroidal and densely covered with scabers. The paratabulation is of the impagidinium type, indicated by high parasutural septa (30 to 40% of the diameter of the central body) whose distal margins are constantly split into low, entirely crenulated to denticulate ridges arranged in a V-shape; its formula is as follows: 4', 6". 6c, 6'", 1 p, 1 pv, 5s. Between 6" and the parasulcus, the " and lc,5"' and 6c, 1"' and the parasulcus, lp and 1 pv and between the sulcal paraplates, the parasutural septa are constantly absent and replaced by very fine lines.
Dimensions:
Holotype: Total diameter: 60 µm; central body, length: 44 µm, width: 38 µm.
Variation: Total diameter: 60-80 µm; central body, length: 40-60 µm, width: 38-54 µm.
Paracingulum width: 4-8 µm.
Septa height: 16-20 µm.
Number of specimens measured: 15.
Material: > 20 specimens.
Description:The 1.5 to 2 pm thick autophragm is densely scabrated. The parasutural septa are straight, slightly scabrated and supported by strong, thin axes located at the points of their gonal junctions. The ridges resulting from the distal splitting of the parasutural septa are often more developed on the gonal regions where they are well separated in superior view; this extremely distal bifurcation of the septa consists in fact only of a splitting of the distal ornaments (crenulures and denticles). The paracingulum is segmented and strongly laevogyrous. The archaeopyle is precingulate of type P (3" only) with a pentagonal outline; the operculum is free.
Comparison:
lmpagidinium scabrosum sp. nov. is characterized by its septa bifurcating distally into low crenate to denticulate ridges, by the particular arrangement of the sulcal paraplates and by the absence of septa between some paraplates (see description above). It has the same appearance as Pterodinium aliferum Eisenack (1958a) understands SARJEANT (1985a) especially by the distal ornamentation of the septa, but the latter differs by its undivided septa, by the different arrangement of the sulcal paraplates and also by the presence of most of the septa which are missing in the present species. Pterodinium agadirense Below (1981 a), from the Gargasian (Morocco) also has tall septa, split distally in the same way as in the species studied here, but it is distinguished by its smooth double-membrane cyst, by the presence of an apical horn formed by the septa and also by its paratabulation which, according to Below (1981a: p. 112), corresponds to that of Pterodinium premnon Duxbury (1980). Pterodinium mamounia Below (1981 a), from the Gargasian (Morocco) has an oval, elongated, double-walled central body and bears an apical horn; its parasutural septa are not split distally and its ventral paratabulation is very different from that of impagidinium scabrosum sp. nov.
Impagidinium scabrosum Slimani, 1994, p.105–107, pl.17, figs.10–15; text-fig.13B. Holotype: Slimani, 1994, pl.17, figs.10–11. Age: late Campanian–earliest Maastrichtian.
---------------------------------------------------------------------------------------------------
Original description (Slimani, 1994)
Diagnosis: Murochorate, aeavate cyst, generally polygonal in outline. The central body is ovoid to subspheroidal and densely covered with scabers. The paratabulation is of the impagidinium type, indicated by high parasutural septa (30 to 40% of the diameter of the central body) whose distal margins are constantly split into low, entirely crenulated to denticulate ridges arranged in a V-shape; its formula is as follows: 4', 6". 6c, 6'", 1 p, 1 pv, 5s. Between 6" and the parasulcus, the " and lc,5"' and 6c, 1"' and the parasulcus, lp and 1 pv and between the sulcal paraplates, the parasutural septa are constantly absent and replaced by very fine lines.
Dimensions:
Holotype: Total diameter: 60 µm; central body, length: 44 µm, width: 38 µm.
Variation: Total diameter: 60-80 µm; central body, length: 40-60 µm, width: 38-54 µm.
Paracingulum width: 4-8 µm.
Septa height: 16-20 µm.
Number of specimens measured: 15.
Material: > 20 specimens.
Description:The 1.5 to 2 pm thick autophragm is densely scabrated. The parasutural septa are straight, slightly scabrated and supported by strong, thin axes located at the points of their gonal junctions. The ridges resulting from the distal splitting of the parasutural septa are often more developed on the gonal regions where they are well separated in superior view; this extremely distal bifurcation of the septa consists in fact only of a splitting of the distal ornaments (crenulures and denticles). The paracingulum is segmented and strongly laevogyrous. The archaeopyle is precingulate of type P (3" only) with a pentagonal outline; the operculum is free.
Comparison:
lmpagidinium scabrosum sp. nov. is characterized by its septa bifurcating distally into low crenate to denticulate ridges, by the particular arrangement of the sulcal paraplates and by the absence of septa between some paraplates (see description above). It has the same appearance as Pterodinium aliferum Eisenack (1958a) understands SARJEANT (1985a) especially by the distal ornamentation of the septa, but the latter differs by its undivided septa, by the different arrangement of the sulcal paraplates and also by the presence of most of the septa which are missing in the present species. Pterodinium agadirense Below (1981 a), from the Gargasian (Morocco) also has tall septa, split distally in the same way as in the species studied here, but it is distinguished by its smooth double-membrane cyst, by the presence of an apical horn formed by the septa and also by its paratabulation which, according to Below (1981a: p. 112), corresponds to that of Pterodinium premnon Duxbury (1980). Pterodinium mamounia Below (1981 a), from the Gargasian (Morocco) has an oval, elongated, double-walled central body and bears an apical horn; its parasutural septa are not split distally and its ventral paratabulation is very different from that of impagidinium scabrosum sp. nov.