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Petalodinium rhomboideum
From Fensome et al., 2019:
Petalodinium rhomboideum (Alberti, 1961, p.10, pl.1, figs.1–5; pl.12, fig.9) Williams et al., 2015, p.308. Holotype: Alberti, 1961, pl.1, fig.3; pl.12, fig.9. Originally Wetzeliella subgenus Rhombodinium, subsequently Rhombodinium, thirdly Dracodinium, fourthly (and now) Petalodinium. Age: Late Eocene.
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Original description: [Alberti, 1961] (translated from German):
Wetzeliella (Rhombodinium) rhomboidea n. sp.
Plate 1 Figs. 1-5, Plate 12 Fig. 9
Holotype: The specimen preserved in preparation no. A 5 and shown on Plate 1 Fig. 3.
Type locality: Conow Bore.
Type stratum: Upper Eocene.
Diagnosis: Carapace flat, its outline rhombic-oval. Lateral margins smooth, weakly convex. Apical horn small, usually distinct. Lateral horns completely reduced. Of the antapical horns, usually only one is present as a small lobe. Transverse groove rarely on the outer part of the flanks. Membrane of the carapace clear. Inner body thick-walled, oval, with a wide space between it and the outer margin of the carapace
Additional features: The epitheca is somewhat smaller than the hypothecium. A notch in the two lateral margins at the level of the completely reduced lateral horns is usually present. Rarely, the second anticapical horn is also present, but then much smaller than the first. A rounded-trapezoidal emergence hole lies beneath the apex. The carapace membrane is pale yellowish to almost colorless, that of the inner body thick-walled and rough, and brownish in color.
Relationships: The present species differs from W. (Rh.) draco Gocht by the rhombic-oval outline of the carapace, the complete reduction of the lateral horns, and the smaller, thick-walled inner body; from W. (Rh.) glabra Kookson by the absence of a transverse groove, the complete reduction of the lateral horns, and the weakly convex lateral margins
Holotype dimensions: Length 128 μm, width 102 μm; inner body length 75 μm, width 74 μm. In other specimens, the carapace length varies between 117 μm and 144 μm, the width between 97 μm and 109 μm. The length-to-width ratio is approximately 1.2 to 1.35:1.
Material: Over 40 specimens.
Occurrence: Upper Eocene of the Conow borehole.
Petalodinium rhomboideum (Alberti, 1961, p.10, pl.1, figs.1–5; pl.12, fig.9) Williams et al., 2015, p.308. Holotype: Alberti, 1961, pl.1, fig.3; pl.12, fig.9. Originally Wetzeliella subgenus Rhombodinium, subsequently Rhombodinium, thirdly Dracodinium, fourthly (and now) Petalodinium. Age: Late Eocene.
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Original description: [Alberti, 1961] (translated from German):
Wetzeliella (Rhombodinium) rhomboidea n. sp.
Plate 1 Figs. 1-5, Plate 12 Fig. 9
Holotype: The specimen preserved in preparation no. A 5 and shown on Plate 1 Fig. 3.
Type locality: Conow Bore.
Type stratum: Upper Eocene.
Diagnosis: Carapace flat, its outline rhombic-oval. Lateral margins smooth, weakly convex. Apical horn small, usually distinct. Lateral horns completely reduced. Of the antapical horns, usually only one is present as a small lobe. Transverse groove rarely on the outer part of the flanks. Membrane of the carapace clear. Inner body thick-walled, oval, with a wide space between it and the outer margin of the carapace
Additional features: The epitheca is somewhat smaller than the hypothecium. A notch in the two lateral margins at the level of the completely reduced lateral horns is usually present. Rarely, the second anticapical horn is also present, but then much smaller than the first. A rounded-trapezoidal emergence hole lies beneath the apex. The carapace membrane is pale yellowish to almost colorless, that of the inner body thick-walled and rough, and brownish in color.
Relationships: The present species differs from W. (Rh.) draco Gocht by the rhombic-oval outline of the carapace, the complete reduction of the lateral horns, and the smaller, thick-walled inner body; from W. (Rh.) glabra Kookson by the absence of a transverse groove, the complete reduction of the lateral horns, and the weakly convex lateral margins
Holotype dimensions: Length 128 μm, width 102 μm; inner body length 75 μm, width 74 μm. In other specimens, the carapace length varies between 117 μm and 144 μm, the width between 97 μm and 109 μm. The length-to-width ratio is approximately 1.2 to 1.35:1.
Material: Over 40 specimens.
Occurrence: Upper Eocene of the Conow borehole.