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Filisphaera filifera
Filisphaera filifera Bujak, 1984; Emendation: Head, 1994b, p.235.
Holotype: Bujak, 1984, pl.1, figs.7-8; Head, 1994b, pl.3, figs.1-3; Fensome et al., 1993a, figs.1-2 - p.1193.
Paratypes: Bujak, 1984
Locus typicus: Bering Sea
Stratum typicum: Late Miocene-Early Pleistocene
Original description: Bujak, 1984, p. 185
Diagnosis: Spherical to ovoidal dinoflagellate cysts, sometimes with small apical lobe. Cyst with thin inner wall and thicker outer wall composed of radiating fibers. Surface or outer wall granulate. Spines and other projections absent. Cingulum and sulcus absent. Archeopyle precingular, formed by loss of one (3'') or sometimes two (3'' and ?4'') precingular plates.
Dimensions: Cyst length 45 to 60 Ám, breadth 45 to 56 Ám; 20 specimens measured.
Emended Diagnosis. Head (ed.) 1993, p.235-236
Cysts spherical to ovoidal, sometimes with small apical lobe. Cyst wall formed of two closely appressed layers, a thin solid endophragm and thicker periphragm of narrow, radiating, nontabular septa that form a microreticulum. Lumina generally about 1.5 or less in diameter, but size is variable within an individual specimen; larger lumina (up to about 2.011m diameter) have irregularpolygonal shape. Archeopyle precingular, formed by loss or displacement of one (3") or sometimes two (3" and ?4") precingular plates. Operculum free. Archeopyle angles well defined. There are no other indications of paratabulation.
Remarks. Head (ed.) 1993, p. 235-236
New observations on the nature of the periphragm in F. filifera (see Davies, Head, and White in Head and Wrenn, 1992a, p. 8; and herein) warrant the emendation of this species. The periphragm is here regarded as septate and microreticulate, not consisting of radiating fibres with granulate outer wall as originally described (Bujak, 1984). Subdivision of Filisphaera filifera. Two subspecies of Filisphaera filifera are here recognized: Filisphaera filifera subsp. filifera emend. nov. (autonym), holotype described from the Upper Pliocene of the Bering Sea (Bujak, 1984); and Filisphaera filifera subsp. pilosa stat. nov., emend. nov. (basionym = Filisphaera pilosa Bujak & Matsuoka), holotype described from the Lower or Upper Pliocene of the St. George Basin, Bering Sea (Matsuoka and Bujak, 1988). These two subspecies are provisionally distinguished principally by height of periphragmal septa: about 1.7-2.2 Ám for F. filifera filifera versus about 0.8 ,um for the holotype of F. filifera pilosa. Because in modern cysts today thickness of periphragm can be influenced by developmental and environmental conditions, minor differences in periphragm thickness alone are not considered significant at specific level for the genus Filisphaera. Despite the widespread occurrence of Filisphaera filifera in upper Cenozoic deposits of high northern latitudes, few details of morphology have been published and the full range of variability has yet to be elucidated. Such studies, while beyond the scope of the present paper, are very necessary to refine the present treatment of F. filifera and its subspecies, which is here based on six type specimens of Filisphaera filifera subsp. filifera andone(the holotype) of Filisphaera filifera subsp. pilosa. Stratigraphic Range. Filisphaera filifera is known only from higher northern latitudes. It has been recorded from the Upper Oligocene of the North Sea (Zevenboom, this paper; Plate 3, figs. 8, 9; Plate 4, figs. 1-3) and Middle Miocene of the Norwegian Sea (Manum et al., 1989) and DSDP Site 192, northern North Pacific (Bujak,1984, table 1). It has a persistent highest occurrence in the Lower Pleistocene of northern high-latitude sites (de Vernal et al., 1992).
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Filisphaera filifera Bujak, 1984, emend. Head, 1994b. Emended diagnosis from Head (1994b, p. 235). Cysts spherical to ovoidal, sometimes with small apical lobe. Cyst wall formed of two closely appressed layers, a thin solid endophragm and thicker periphragm of narrow, radiating, nontabular septa that form a microreticulum. Lumina generally about 1.5 µm or less in diameter, but size is variable within an individual specimen: larger lumina up to about 2µm in diameter have irregular polygonal shape. Archeopyle precingular formed by loss or displacement of one (3') or sometimes two (3' and ?4') precingular plates. Operculum free. Archeopyle angles well defined. No other indications of paratabulation. The periphragm in Filisphaera is characterized by a more or less continuous microreticulum of high, narrow septa. In Cerebrocysta, there are low, discontinuous sinuous ridges. Tectatodinium has a typically cancellous to fibrous periphragm. Bitectatodinium has a periphragm that lacks a complete reticulate or micoreticulate structure and Habibacysta has a combined tectate/columellate wall structure. Size: length 45-60 µm, width 45-56 µm.
Holotype: Bujak, 1984, pl.1, figs.7-8; Head, 1994b, pl.3, figs.1-3; Fensome et al., 1993a, figs.1-2 - p.1193.
Paratypes: Bujak, 1984
Locus typicus: Bering Sea
Stratum typicum: Late Miocene-Early Pleistocene
Original description: Bujak, 1984, p. 185
Diagnosis: Spherical to ovoidal dinoflagellate cysts, sometimes with small apical lobe. Cyst with thin inner wall and thicker outer wall composed of radiating fibers. Surface or outer wall granulate. Spines and other projections absent. Cingulum and sulcus absent. Archeopyle precingular, formed by loss of one (3'') or sometimes two (3'' and ?4'') precingular plates.
Dimensions: Cyst length 45 to 60 Ám, breadth 45 to 56 Ám; 20 specimens measured.
Emended Diagnosis. Head (ed.) 1993, p.235-236
Cysts spherical to ovoidal, sometimes with small apical lobe. Cyst wall formed of two closely appressed layers, a thin solid endophragm and thicker periphragm of narrow, radiating, nontabular septa that form a microreticulum. Lumina generally about 1.5 or less in diameter, but size is variable within an individual specimen; larger lumina (up to about 2.011m diameter) have irregularpolygonal shape. Archeopyle precingular, formed by loss or displacement of one (3") or sometimes two (3" and ?4") precingular plates. Operculum free. Archeopyle angles well defined. There are no other indications of paratabulation.
Remarks. Head (ed.) 1993, p. 235-236
New observations on the nature of the periphragm in F. filifera (see Davies, Head, and White in Head and Wrenn, 1992a, p. 8; and herein) warrant the emendation of this species. The periphragm is here regarded as septate and microreticulate, not consisting of radiating fibres with granulate outer wall as originally described (Bujak, 1984). Subdivision of Filisphaera filifera. Two subspecies of Filisphaera filifera are here recognized: Filisphaera filifera subsp. filifera emend. nov. (autonym), holotype described from the Upper Pliocene of the Bering Sea (Bujak, 1984); and Filisphaera filifera subsp. pilosa stat. nov., emend. nov. (basionym = Filisphaera pilosa Bujak & Matsuoka), holotype described from the Lower or Upper Pliocene of the St. George Basin, Bering Sea (Matsuoka and Bujak, 1988). These two subspecies are provisionally distinguished principally by height of periphragmal septa: about 1.7-2.2 Ám for F. filifera filifera versus about 0.8 ,um for the holotype of F. filifera pilosa. Because in modern cysts today thickness of periphragm can be influenced by developmental and environmental conditions, minor differences in periphragm thickness alone are not considered significant at specific level for the genus Filisphaera. Despite the widespread occurrence of Filisphaera filifera in upper Cenozoic deposits of high northern latitudes, few details of morphology have been published and the full range of variability has yet to be elucidated. Such studies, while beyond the scope of the present paper, are very necessary to refine the present treatment of F. filifera and its subspecies, which is here based on six type specimens of Filisphaera filifera subsp. filifera andone(the holotype) of Filisphaera filifera subsp. pilosa. Stratigraphic Range. Filisphaera filifera is known only from higher northern latitudes. It has been recorded from the Upper Oligocene of the North Sea (Zevenboom, this paper; Plate 3, figs. 8, 9; Plate 4, figs. 1-3) and Middle Miocene of the Norwegian Sea (Manum et al., 1989) and DSDP Site 192, northern North Pacific (Bujak,1984, table 1). It has a persistent highest occurrence in the Lower Pleistocene of northern high-latitude sites (de Vernal et al., 1992).
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Filisphaera filifera Bujak, 1984, emend. Head, 1994b. Emended diagnosis from Head (1994b, p. 235). Cysts spherical to ovoidal, sometimes with small apical lobe. Cyst wall formed of two closely appressed layers, a thin solid endophragm and thicker periphragm of narrow, radiating, nontabular septa that form a microreticulum. Lumina generally about 1.5 µm or less in diameter, but size is variable within an individual specimen: larger lumina up to about 2µm in diameter have irregular polygonal shape. Archeopyle precingular formed by loss or displacement of one (3') or sometimes two (3' and ?4') precingular plates. Operculum free. Archeopyle angles well defined. No other indications of paratabulation. The periphragm in Filisphaera is characterized by a more or less continuous microreticulum of high, narrow septa. In Cerebrocysta, there are low, discontinuous sinuous ridges. Tectatodinium has a typically cancellous to fibrous periphragm. Bitectatodinium has a periphragm that lacks a complete reticulate or micoreticulate structure and Habibacysta has a combined tectate/columellate wall structure. Size: length 45-60 µm, width 45-56 µm.