Back
Triblastula borussica
Triblastula borussica (Eisenack, 1954) Morgenroth, 1966
NOW Rottnestia. Originally Hystrichosphaera, subsequently (and now) Rottnestia, thirdly Triblastula, fourthly Hystrichosphaeropsis (combination not validly published).
Taxonomic junior synonym: Hystrichosphaeropsis jubata (name not validly published), according to May (1980, p.24).
Holotype: Eisenack, 1954, pl.9, fig.5
Age: Early Oligocene
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP
Rottnestia borussica (Eisenack, 1954b) Cookson and Eisenack, 1961b. Diagnosis according to Eisenack (1954b, p.62), central body ovoidal, same tabulation as in H.speciosa or H.wetzelii. The lower pole displays an extensive system of wing lists which extends up to the equatorial zone; however, in contrast to H.wetzelii such a wing-list system is generally missing here on the upper pole. Size: length 80-108 µm, central body length 55 µm, width 50 µm. Description, according to Cookson and Eisenack (1961b), Shell considerably longer than broad, with a prominent internal body which is in contact with the pericyst except at the poles. Both apical and antapical expansions of the outer membrane are usually strongly developed. The apical expansion narrows distally; its margins are rather deeply embayed and in perfect specimens it bears a well defined median cylindrical horn. The antapical expansion is broader angular in section and is supported by 5 or 6 (usually 6) ledges. The girdle is clearly defined and crossed on the dorsal surface by vertical ledges which mark out transversely elongate-rhombic areas. The longitudinal furrow runs obliquely across the ventral surface from the base of the apical expansion almost to the upper limit of the antapex. Both the epitheca and hypotheca have more or less clearly defined fields which, usually, are longer than broad; their boundaries run to the outer limits of the shell. Furcate appendages arise from gonal positions. A few Rottnestia specimens have no processes.
--------------------------------------------------
REMARK: the specimens depicted in Eisenack, 1954, are oriented upside-down.
Diagnosis: Central body oval, tabulation like in H. speciosa or H. wetzeli, the lower pole bearing an extensive system of wing-ledges, reaching onto the equatorial zone, but, in contrast to H. wetzeli, absent on the upper pole.
Description (annotated): The tabulation of the approximately oval central body is determined by septa, similar to those in H. speciosa and H. wetzeli, viz.
NOW Rottnestia. Originally Hystrichosphaera, subsequently (and now) Rottnestia, thirdly Triblastula, fourthly Hystrichosphaeropsis (combination not validly published).
Taxonomic junior synonym: Hystrichosphaeropsis jubata (name not validly published), according to May (1980, p.24).
Holotype: Eisenack, 1954, pl.9, fig.5
Age: Early Oligocene
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP
Rottnestia borussica (Eisenack, 1954b) Cookson and Eisenack, 1961b. Diagnosis according to Eisenack (1954b, p.62), central body ovoidal, same tabulation as in H.speciosa or H.wetzelii. The lower pole displays an extensive system of wing lists which extends up to the equatorial zone; however, in contrast to H.wetzelii such a wing-list system is generally missing here on the upper pole. Size: length 80-108 µm, central body length 55 µm, width 50 µm. Description, according to Cookson and Eisenack (1961b), Shell considerably longer than broad, with a prominent internal body which is in contact with the pericyst except at the poles. Both apical and antapical expansions of the outer membrane are usually strongly developed. The apical expansion narrows distally; its margins are rather deeply embayed and in perfect specimens it bears a well defined median cylindrical horn. The antapical expansion is broader angular in section and is supported by 5 or 6 (usually 6) ledges. The girdle is clearly defined and crossed on the dorsal surface by vertical ledges which mark out transversely elongate-rhombic areas. The longitudinal furrow runs obliquely across the ventral surface from the base of the apical expansion almost to the upper limit of the antapex. Both the epitheca and hypotheca have more or less clearly defined fields which, usually, are longer than broad; their boundaries run to the outer limits of the shell. Furcate appendages arise from gonal positions. A few Rottnestia specimens have no processes.
--------------------------------------------------
REMARK: the specimens depicted in Eisenack, 1954, are oriented upside-down.
Diagnosis: Central body oval, tabulation like in H. speciosa or H. wetzeli, the lower pole bearing an extensive system of wing-ledges, reaching onto the equatorial zone, but, in contrast to H. wetzeli, absent on the upper pole.
Description (annotated): The tabulation of the approximately oval central body is determined by septa, similar to those in H. speciosa and H. wetzeli, viz.