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Bianchina hieroglyphica
Bianchina *hieroglyphica, Schiøler, 2015, p.410–411, (p.5–6 in PDF initially published online), pl.1, figs.1–12; text-fig.3.
Holotype: Schiøler, 2015, pl.1, figs.6–7.
Horizon: Loose block of Tikihore Formation collected at Port Awanui.
Paratypes: Sample Z15/f83, SM519, EF coordinates L40/1, Plate 1, figures 1, 2. Sample Z15/f83, SM511, EF coordinates H38/0, Plate 1, figures 8, 9. Sample Z15/f83, SM523, EF coordinates P39/2, Plate 1, figures 11–13.
Stratigraphical range: Mid-Cretaceous, Late Albian to Middle Cenomanian (Urutawan to Ngaterian).
Age: late Albian–middle Cenomanian
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Original description: [Schiøler, 2015]:
Description:
Subspherical to slightly mono- or biconical, dorsoventrally compressed, single-layered peridinioid cyst of intermediate to large size. Characteristically, most views of the cyst are ambital, due to its dorsoventral compression. The epicyst is sub-hemispherical in most specimens, slightly conical in rare cases. The hypocyst is smaller than the epicyst and slightly conical in most specimens, with an acute antapex typically bearing a short antapical boss (length c 2–5 μm, Plate 1, figures 1, 3, 9). Otherwise, the cyst is without protrusions or horns. In most specimens, the epicyst is well-rounded and lacks an apical protrusion. In a few specimens, the epicyst also appears slightly conical (Plate 1, figure 3).
The cyst has a characteristic, low-relief, reticulate surface ornament resembling ancient Egyptian hieroglyphs (Plate 1, figure 4). The ornament is penitabular and reflects a peridinioid tabulation, more clearly so on the dorsal surface than on the ventral surface (compare Plate 1, figures 1 and 2, figures 6 and 7, figures 12 and 13).
The cingulum is clearly visible and has a slight sinistral offset of one cingular width (Plate 1, figure 10); it divides the cyst into a larger epicyst and a smaller hypocyst. In most specimens, the individual plates of the cingulum are visible, indicated by the penitabular ornament (Plate 1, figures 4, 7, 8).
The sulcus is large and indicated by a smoother area with suppressed ornamentation.
The archaeopyle is of combination type, formed by sutures between all three intercalary plates (1–3a) and the three mid-dorsal precingulars (3–5′′). The operculum is compound with adnate opercular pieces. The attachment is adapical for the intercalary plates and adcingular for the precingular plates (Figure 3; Plate 1, figures 2, 7, 8). Specimens with free opercular plates were not observed in any of the material studied. The archaeopyle formula is 3Ia3Pa3–5′′.
The tabulation formula is ?pr, 4', 3a, 7′′, 4c, 5′′', ?p, 2′′′′.
Affinities/Remarks:
Bianchina hieroglyphica has some superficial resemblance to Laciniadinium tenuistriatum in overall shape and in the possession of surface ornament, but differs in its archaeopyle type and in having its tabulation shown by the penitabular ornament. The new species differs from all other species of Laciniadinium as well as species of Luxadinium and Saeptodinium, with which it may also have some superficial resemblance in shape, in its archaeopyle type and in its penitabular hieroglyph-like ornament. The new species further differs from species of Ginginodinium and Diconodinium in having a subcircular ambitus, as opposed to the pentagonal ambitus of Ginginodinium and the biconical shape of Diconodinium.
Holotype: Schiøler, 2015, pl.1, figs.6–7.
Horizon: Loose block of Tikihore Formation collected at Port Awanui.
Paratypes: Sample Z15/f83, SM519, EF coordinates L40/1, Plate 1, figures 1, 2. Sample Z15/f83, SM511, EF coordinates H38/0, Plate 1, figures 8, 9. Sample Z15/f83, SM523, EF coordinates P39/2, Plate 1, figures 11–13.
Stratigraphical range: Mid-Cretaceous, Late Albian to Middle Cenomanian (Urutawan to Ngaterian).
Age: late Albian–middle Cenomanian
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Original description: [Schiøler, 2015]:
Description:
Subspherical to slightly mono- or biconical, dorsoventrally compressed, single-layered peridinioid cyst of intermediate to large size. Characteristically, most views of the cyst are ambital, due to its dorsoventral compression. The epicyst is sub-hemispherical in most specimens, slightly conical in rare cases. The hypocyst is smaller than the epicyst and slightly conical in most specimens, with an acute antapex typically bearing a short antapical boss (length c 2–5 μm, Plate 1, figures 1, 3, 9). Otherwise, the cyst is without protrusions or horns. In most specimens, the epicyst is well-rounded and lacks an apical protrusion. In a few specimens, the epicyst also appears slightly conical (Plate 1, figure 3).
The cyst has a characteristic, low-relief, reticulate surface ornament resembling ancient Egyptian hieroglyphs (Plate 1, figure 4). The ornament is penitabular and reflects a peridinioid tabulation, more clearly so on the dorsal surface than on the ventral surface (compare Plate 1, figures 1 and 2, figures 6 and 7, figures 12 and 13).
The cingulum is clearly visible and has a slight sinistral offset of one cingular width (Plate 1, figure 10); it divides the cyst into a larger epicyst and a smaller hypocyst. In most specimens, the individual plates of the cingulum are visible, indicated by the penitabular ornament (Plate 1, figures 4, 7, 8).
The sulcus is large and indicated by a smoother area with suppressed ornamentation.
The archaeopyle is of combination type, formed by sutures between all three intercalary plates (1–3a) and the three mid-dorsal precingulars (3–5′′). The operculum is compound with adnate opercular pieces. The attachment is adapical for the intercalary plates and adcingular for the precingular plates (Figure 3; Plate 1, figures 2, 7, 8). Specimens with free opercular plates were not observed in any of the material studied. The archaeopyle formula is 3Ia3Pa3–5′′.
The tabulation formula is ?pr, 4', 3a, 7′′, 4c, 5′′', ?p, 2′′′′.
Affinities/Remarks:
Bianchina hieroglyphica has some superficial resemblance to Laciniadinium tenuistriatum in overall shape and in the possession of surface ornament, but differs in its archaeopyle type and in having its tabulation shown by the penitabular ornament. The new species differs from all other species of Laciniadinium as well as species of Luxadinium and Saeptodinium, with which it may also have some superficial resemblance in shape, in its archaeopyle type and in its penitabular hieroglyph-like ornament. The new species further differs from species of Ginginodinium and Diconodinium in having a subcircular ambitus, as opposed to the pentagonal ambitus of Ginginodinium and the biconical shape of Diconodinium.