Back
Fromea complicata
From Fensome et al., 2019:
Fromea complicata Brideaux, 1977, p.18–19, pl.7, figs.1–6. Holotype: Brideaux, 1977, pl.7, figs.1–2. Taxonomic senior synonym: Tenua (as Fromea) atlantica, according to Davies (1983, p.31) — however, Jansonius (1989, p.65) retained Fromea complicata. Age: Aptian–Albian.
---------------------------------------------------------------------------------------------------
Original diagnosis: Brideaux, 1977, p. 18-19
Shape: Autocyst distinctly longer than broad, maximum width at the mid-line (usually the presum position of the pericingulum), tapering and rounded at both apices; dorso-ventral compression.
Phragma: Autophragm about 1 µm thick; smooth or scabrate; two major fold systems interpreted as related to position of the pericingulum and perisulcus; numerous other minor wrinkles and folds.
Paratabulation: Evidence for determinable paratabulation lacking.
Archeopyle/operculum: A subangular to irregular opening, presumably situated at the apex, is interpreted as an apical archeopyle; operculum free and simple, not observed separately. Formula A.
Pericingulum/perisulcus: A major transverse fold system present on all observed specimens, rarely (holotype) associated with a lateral invagination at the mid-line, interpreted as indicating presence of a pericingulum; a major longitudinal fold system, extending the length of the autocyst, appearing to be ventral to the pericingulum fold system, interpreted as indicating the presence of a perisulcus.
Variation: The pericingular fold system, on some specimens, appears offset and somewhat helicoid; on most specimens, however, it occurs only on one surface.
Dimensions: Autocyst length, 58-80 µm; autocyst width, 43-60 µm. Autocyst length, 41-96 µm; autocyst width, 27-64 µm.
Fromea complicata Brideaux, 1977, p.18–19, pl.7, figs.1–6. Holotype: Brideaux, 1977, pl.7, figs.1–2. Taxonomic senior synonym: Tenua (as Fromea) atlantica, according to Davies (1983, p.31) — however, Jansonius (1989, p.65) retained Fromea complicata. Age: Aptian–Albian.
---------------------------------------------------------------------------------------------------
Original diagnosis: Brideaux, 1977, p. 18-19
Shape: Autocyst distinctly longer than broad, maximum width at the mid-line (usually the presum position of the pericingulum), tapering and rounded at both apices; dorso-ventral compression.
Phragma: Autophragm about 1 µm thick; smooth or scabrate; two major fold systems interpreted as related to position of the pericingulum and perisulcus; numerous other minor wrinkles and folds.
Paratabulation: Evidence for determinable paratabulation lacking.
Archeopyle/operculum: A subangular to irregular opening, presumably situated at the apex, is interpreted as an apical archeopyle; operculum free and simple, not observed separately. Formula A.
Pericingulum/perisulcus: A major transverse fold system present on all observed specimens, rarely (holotype) associated with a lateral invagination at the mid-line, interpreted as indicating presence of a pericingulum; a major longitudinal fold system, extending the length of the autocyst, appearing to be ventral to the pericingulum fold system, interpreted as indicating the presence of a perisulcus.
Variation: The pericingular fold system, on some specimens, appears offset and somewhat helicoid; on most specimens, however, it occurs only on one surface.
Dimensions: Autocyst length, 58-80 µm; autocyst width, 43-60 µm. Autocyst length, 41-96 µm; autocyst width, 27-64 µm.