Back
Fromea atlantica
Fromea atlantica (Habib, 1972) Davies, 1983
Now Valvaeodinium. Originally Tenua Eisenack, 1958a, subsequently Sentusidinium?, thirdly Fromea, fourthly Kylindrocysta, fifthly (and now) Valvaeodinium.
Tax. sr. synonym of Fromea complicata Brideaux, 1977, according to Davies, 1983. Jansonius, 1989, retained Fromea complicata as a separate species.
Holotype: Habib, 1972, pl.4, fig.2
Locus typicus: DSDP Leg.11 Site , North Atlantic
Stratum typicum: Callovian-Oxfordian
Original description: Habib, 1972, p. 375: Tenua atlantica
Relatively small untabulated proximate cysts. Outline of hypotract rectangular, epitract triangular. Hypotract same size or slightly larger than epitract. Cyst longer than wide; it is widest in the region of the cingulum, although a distinctive cingulum is not evident. Apical archeopyle small; its margin is zig-zag suggesting six precingular plates and a sulcus below; operculum triangular but well-rounded. Wall is thin and densely granulate. Maximum size of seven measured specimens 24 to 35 Ám.
Affinities:
Habib, 1972, p. 375: Tenua atlantica
This species of Tenua is distinguished by its form and small apical archeopyle. In several specimens, including the holotype, there is evidence of faint sutures reflecting a minimum of six precingular plates and five or six postcingular plates. Further detailed examination of additional specimens is necessary before it can be determined if a tabulation is present.
Now Valvaeodinium. Originally Tenua Eisenack, 1958a, subsequently Sentusidinium?, thirdly Fromea, fourthly Kylindrocysta, fifthly (and now) Valvaeodinium.
Tax. sr. synonym of Fromea complicata Brideaux, 1977, according to Davies, 1983. Jansonius, 1989, retained Fromea complicata as a separate species.
Holotype: Habib, 1972, pl.4, fig.2
Locus typicus: DSDP Leg.11 Site , North Atlantic
Stratum typicum: Callovian-Oxfordian
Original description: Habib, 1972, p. 375: Tenua atlantica
Relatively small untabulated proximate cysts. Outline of hypotract rectangular, epitract triangular. Hypotract same size or slightly larger than epitract. Cyst longer than wide; it is widest in the region of the cingulum, although a distinctive cingulum is not evident. Apical archeopyle small; its margin is zig-zag suggesting six precingular plates and a sulcus below; operculum triangular but well-rounded. Wall is thin and densely granulate. Maximum size of seven measured specimens 24 to 35 Ám.
Affinities:
Habib, 1972, p. 375: Tenua atlantica
This species of Tenua is distinguished by its form and small apical archeopyle. In several specimens, including the holotype, there is evidence of faint sutures reflecting a minimum of six precingular plates and five or six postcingular plates. Further detailed examination of additional specimens is necessary before it can be determined if a tabulation is present.