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Phthanoperidinium rothmaniae
Phthanoperidinium rothmaniae Stotland in Andreeva-Grigorovich et al., 2011, p.36–38, pl.53, figs.1–9; pl.54, figs.1–3. Holotype: Andreeva-Grigorovich et al., 2011, pl.53, figs.1–9. Age: Rupelian.
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Original description: [Andreeva-Grigorovich et al., 2011] (translated from Russian):
Phthanoperidinium rothmaniae Stotland sp. nov. - Tabl. LIII, 1-9; LIV, 1-3
Name. In honor of Raisa Nazarovna Rotman, a famous paleopalynologist of Ukraine.
Diagnosis. Peridiniacean, rounded, acavate-cornucavate cyst with distinct tabulation expressed by low ridges, dorsoventrally compressed. Small apical horn is triangular in shape, the left antapical horn is well developed and distally shar-pened, a right antapical horn close by pressed to left one and very much redu-ced. Peri- and endophragm closely appressed except for the horns top, where very small pericels is developed.
Description: Peridinioid acavacate-cornucavate cyst of discoid shape with distinct paratabulation. Outline in dorsoventral projection is rounded, in the lateral it is elongated-elliptical. The "compression" coefficient (the ratio of the length of the dorsoventral axis to the lateral one) is 0.3-0.4. The epicyst is equal in length to the hypocyst or slightly longer. The apical horn is small (up to 5 µm), triangular (Table LIII) or trapezoidal (Table LIV, 2a) in shape. The left antapical horn is pointed distally, its length is usually equal to the length of the apical horn (Tables LIII, 6; LIV, 16, 26, 36). The right antapical horn is close to the left, significantly reduced (Table LIV, 16, 26, 2g) or not expressed at all (Table LIV, 3a-3g).
The periphragm and endophragm are tightly pressed against each other, excluding the pandasural areas and the upper parts of the apical and antapical horns, where a small pericoel is formed. The periphragm is thin, transparent, and the sculpture of its surface is fine-grained. In plan, the granular sculpture of the surface of the presingular plates of the paratabulation (1-7", 1-5) is a pattern of polygons (or forms close to them) nested within each other with a common wide base turned toward the singulum. This pattern smoothly passes into a distinct vertical shading of the suture ridges (Pl. LIV, 16). The endophragm is significantly thicker than the periphragm. Both phragms participate in the formation of the structure of the horns and parasutural ridges.
The paratabulation formula and the outline of individual plates are normal for representatives of the genus: 4', 3a, 7", 6c, 5''', 2"". The ventral paratabulation has a distinct orthostyle (according to Goodman et al., 1983) — plate 1' contacts two presingular 1" and 7" (Pl. LIII, 2, 4, 3a; LIV, 3a). The parasingulum is relatively wide (up to 7 µm; Pl. LIV, 2c), always narrowing toward the parasulcus, helicoid, twisted to the left by no more than half its width. The parasulcus is very narrow at the ends of the singularum, roundly widening toward the antapex. The archaeopile is intercalary combined, type 31, the operculum is free.
Holotype. Plate LIII, 1–9. Preparation 79022-82-05 (coordinates relative to the lower left corner of the coverslip: 28.3 × 6.8). Paratypes: Plate LIV, preparation 79022-82-08: first, figs. 1a–1g (19.7 × 6.2); second, figs. 2a–2g (16.2 × 19.8); third, figs. 3a–3g (9.7 × 15.6).
Location. Outcrop near the village of Novi Petrovtsy, Mezhyhirya suite (amber-bearing layers) (Kiev region, right bank of the Dnieper River).
Dimensions (µm). Holotype: pericyst length 56; pericyst width 46; horn height: apical 5, left antapical - 5; paracingulum width up to 6. Other specimens (22 specimens): pericyst length - 54-56; pericyst width 45-48; horn height: apical 4-6, left antapical - 5.0-7.5; paracingulum width up to 7.5.
Comparison. The most morphologically similar to the described new species are Ph. amiculum Liengjarern et al., 1980 and Ph. amoenum Drugg et Loeblich Јг., 1967. Unlike Ph. amiculum, the small sculptural elements of the periphragm of which (according to Liengjarern et al., 1980) are organized into distinct penitabular ring structures, the described species does not have such a form of surface relief. This species also differs from Ph. amoenum and Ph. amiculum in its rounded outline, significant dorsoventral "compression", and the presence of a pointed antapical horn equal in size to the apical one. According to the roundness of the outline of the cyst in the lateral plane, the described species may be to some extent compared with the species Ph. brooksii Edwards et Bebout, 1981. However, the latter differs in its general rounded-angular shape, smaller size and special metastyle of the ventral paratabulation with contact of plate 1 with three presingular plates 1", 6" and 7" (according to Goodman et al., 1983).
Distribution. Ukraine, Zhitomir region, Yemilchansky district, Barashivska amber-bearing zone, Viktorovskaya area; Kiev region, outcrop near the village of Novi Petrovtsy, Mezhyhirya suite (amber-bearing layers). Lower Oligocene (Rupelian).
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Original description: [Andreeva-Grigorovich et al., 2011] (translated from Russian):
Phthanoperidinium rothmaniae Stotland sp. nov. - Tabl. LIII, 1-9; LIV, 1-3
Name. In honor of Raisa Nazarovna Rotman, a famous paleopalynologist of Ukraine.
Diagnosis. Peridiniacean, rounded, acavate-cornucavate cyst with distinct tabulation expressed by low ridges, dorsoventrally compressed. Small apical horn is triangular in shape, the left antapical horn is well developed and distally shar-pened, a right antapical horn close by pressed to left one and very much redu-ced. Peri- and endophragm closely appressed except for the horns top, where very small pericels is developed.
Description: Peridinioid acavacate-cornucavate cyst of discoid shape with distinct paratabulation. Outline in dorsoventral projection is rounded, in the lateral it is elongated-elliptical. The "compression" coefficient (the ratio of the length of the dorsoventral axis to the lateral one) is 0.3-0.4. The epicyst is equal in length to the hypocyst or slightly longer. The apical horn is small (up to 5 µm), triangular (Table LIII) or trapezoidal (Table LIV, 2a) in shape. The left antapical horn is pointed distally, its length is usually equal to the length of the apical horn (Tables LIII, 6; LIV, 16, 26, 36). The right antapical horn is close to the left, significantly reduced (Table LIV, 16, 26, 2g) or not expressed at all (Table LIV, 3a-3g).
The periphragm and endophragm are tightly pressed against each other, excluding the pandasural areas and the upper parts of the apical and antapical horns, where a small pericoel is formed. The periphragm is thin, transparent, and the sculpture of its surface is fine-grained. In plan, the granular sculpture of the surface of the presingular plates of the paratabulation (1-7", 1-5) is a pattern of polygons (or forms close to them) nested within each other with a common wide base turned toward the singulum. This pattern smoothly passes into a distinct vertical shading of the suture ridges (Pl. LIV, 16). The endophragm is significantly thicker than the periphragm. Both phragms participate in the formation of the structure of the horns and parasutural ridges.
The paratabulation formula and the outline of individual plates are normal for representatives of the genus: 4', 3a, 7", 6c, 5''', 2"". The ventral paratabulation has a distinct orthostyle (according to Goodman et al., 1983) — plate 1' contacts two presingular 1" and 7" (Pl. LIII, 2, 4, 3a; LIV, 3a). The parasingulum is relatively wide (up to 7 µm; Pl. LIV, 2c), always narrowing toward the parasulcus, helicoid, twisted to the left by no more than half its width. The parasulcus is very narrow at the ends of the singularum, roundly widening toward the antapex. The archaeopile is intercalary combined, type 31, the operculum is free.
Holotype. Plate LIII, 1–9. Preparation 79022-82-05 (coordinates relative to the lower left corner of the coverslip: 28.3 × 6.8). Paratypes: Plate LIV, preparation 79022-82-08: first, figs. 1a–1g (19.7 × 6.2); second, figs. 2a–2g (16.2 × 19.8); third, figs. 3a–3g (9.7 × 15.6).
Location. Outcrop near the village of Novi Petrovtsy, Mezhyhirya suite (amber-bearing layers) (Kiev region, right bank of the Dnieper River).
Dimensions (µm). Holotype: pericyst length 56; pericyst width 46; horn height: apical 5, left antapical - 5; paracingulum width up to 6. Other specimens (22 specimens): pericyst length - 54-56; pericyst width 45-48; horn height: apical 4-6, left antapical - 5.0-7.5; paracingulum width up to 7.5.
Comparison. The most morphologically similar to the described new species are Ph. amiculum Liengjarern et al., 1980 and Ph. amoenum Drugg et Loeblich Јг., 1967. Unlike Ph. amiculum, the small sculptural elements of the periphragm of which (according to Liengjarern et al., 1980) are organized into distinct penitabular ring structures, the described species does not have such a form of surface relief. This species also differs from Ph. amoenum and Ph. amiculum in its rounded outline, significant dorsoventral "compression", and the presence of a pointed antapical horn equal in size to the apical one. According to the roundness of the outline of the cyst in the lateral plane, the described species may be to some extent compared with the species Ph. brooksii Edwards et Bebout, 1981. However, the latter differs in its general rounded-angular shape, smaller size and special metastyle of the ventral paratabulation with contact of plate 1 with three presingular plates 1", 6" and 7" (according to Goodman et al., 1983).
Distribution. Ukraine, Zhitomir region, Yemilchansky district, Barashivska amber-bearing zone, Viktorovskaya area; Kiev region, outcrop near the village of Novi Petrovtsy, Mezhyhirya suite (amber-bearing layers). Lower Oligocene (Rupelian).