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Pentadinium favatum
Pentadinium favatum Edwards, 1982
Holotype: Edwards, 1982, pl.1, figs. 4,7,10; Jan du Chene et al., 1986, pl.82, figs.1-5
Locus typicus: Monroe County, Alabama (loc. 4).
Stratum typicum: Tallahatta Formation (middle Eocene)
Occurrences: Tallahatta and lower part of Lisbon Formations (middle Eocene) in western and central Alabama (locs. 2, 3, 7), subsurface Georgia (locs. 9, 10).
Age: Middle Eocene
Original diagnosis: Edwards 1982, p. 113: Pentadinium favatum
A species of Pentadinium with a moderately thick, spongy or honeycombed endophragm and a delicately meshed periphragm, which forms a raised paracingular area and parasutural crests; height of the paracingular area and parasutural crests subequal and extremely variable.
Description: Edwards 1982, p. 113: Pentadinium favatum
Cysts subspherical, endophragm consists of a network of pustules with circular craters or coverings; periphragm delicate, meshlike, with numerous, irregularly spaced holes of varying size; periphragm often incomplete ventrally and in some specimens incomplete and detached from endophragm at plate interiors (see especially, Pl. 2, figs. 8-9); paratabulation gonyaulacacean, 2-3", 5-6", Xc, 5 " ", Ip, I " ", s, indicated by parasutural folds of the periphragm, may be reduced or incompletely expressed; archeopyle precingular, type P (3 " " " " only), operculum free; paracingular region indicated by broad fold in periphragm, strongly helicoid; parasulcal area broad and lacking periphragm.
Dimensions:
Diameter of entire specimen, average 93 µm (range 69-129 µm); diameter of endocyst, average 71 µm (range 58-90 µm); 37 specimens measured;
dimensions of holotype, entire 85 µm, endocyst 64 µm.
Remarks: Specimens in the Alabama material show a tendency for thinning of the endocyst and detachment of the periphragm upsection (Plate 2, figs. 8, 9).
Affinities/Comparisons:
The distinctive surface texture of P. favatum n. sp. separates it from all other species of Pentadinium. It closely resembles and is most probably descended from H. goodmanii n. sp. These two species are separated by the complete crest in the paracingular region of P. favatum and the presence of gonal processes in H. goodmanii.
Holotype: Edwards, 1982, pl.1, figs. 4,7,10; Jan du Chene et al., 1986, pl.82, figs.1-5
Locus typicus: Monroe County, Alabama (loc. 4).
Stratum typicum: Tallahatta Formation (middle Eocene)
Occurrences: Tallahatta and lower part of Lisbon Formations (middle Eocene) in western and central Alabama (locs. 2, 3, 7), subsurface Georgia (locs. 9, 10).
Age: Middle Eocene
Original diagnosis: Edwards 1982, p. 113: Pentadinium favatum
A species of Pentadinium with a moderately thick, spongy or honeycombed endophragm and a delicately meshed periphragm, which forms a raised paracingular area and parasutural crests; height of the paracingular area and parasutural crests subequal and extremely variable.
Description: Edwards 1982, p. 113: Pentadinium favatum
Cysts subspherical, endophragm consists of a network of pustules with circular craters or coverings; periphragm delicate, meshlike, with numerous, irregularly spaced holes of varying size; periphragm often incomplete ventrally and in some specimens incomplete and detached from endophragm at plate interiors (see especially, Pl. 2, figs. 8-9); paratabulation gonyaulacacean, 2-3", 5-6", Xc, 5 " ", Ip, I " ", s, indicated by parasutural folds of the periphragm, may be reduced or incompletely expressed; archeopyle precingular, type P (3 " " " " only), operculum free; paracingular region indicated by broad fold in periphragm, strongly helicoid; parasulcal area broad and lacking periphragm.
Dimensions:
Diameter of entire specimen, average 93 µm (range 69-129 µm); diameter of endocyst, average 71 µm (range 58-90 µm); 37 specimens measured;
dimensions of holotype, entire 85 µm, endocyst 64 µm.
Remarks: Specimens in the Alabama material show a tendency for thinning of the endocyst and detachment of the periphragm upsection (Plate 2, figs. 8, 9).
Affinities/Comparisons:
The distinctive surface texture of P. favatum n. sp. separates it from all other species of Pentadinium. It closely resembles and is most probably descended from H. goodmanii n. sp. These two species are separated by the complete crest in the paracingular region of P. favatum and the presence of gonal processes in H. goodmanii.