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Pontiadinium inequicornutum
Pontadinium inequicornutum Baltes, 1971 ex Stover and Evitt, 1978
Now Komewuia. Originally Diconodinium (name not validly published), subsequently Pontiadinium, thirdly (and now) Komewuia. Baltes, 1971, included this species in the genus Diconodinium but failed to designate a holotype; therefore, according to I.C.B.N. Article 37, the name was not validly published. Stover and Evitt, 1978 designated as lectotype the specimen illustrated in Baltes, 1971. Since this taxon was validated by Stover and Evitt, 1978, Lentin and Williams, 1989 accepted the specimen illustrated in Baltes, 1971 as the holotype.
Holotype: Baltes, 1971, pl.2, fig.2 designated by Stover and Evitt, 1978, p.180 as Lectotype
Locus typicus: Romania
Stratum typicum: Early Pliocene
Original description: Baltes 1971, p. 5: Diconodinium inequicornutum
Test fusiform with straight or slightly concave edges, without tabulation. Epitract, larger than hypotract, is terminated by a single, cone-shaped, prominent horn, 10 to 15 µm long. Antapical part is likewise provided with a horn which is, however, shorter, cylindrical, with a rounded tip. Median part of the test, in the cingulum zone, shows a circular thickening of the outer membrane. In the epitract, having a precingular position, an archeopyle-like opening is visible. External membrane is smooth or finely stippled, and shows some longitudinal thickenings.
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Emended description Baranyi et al., 2022:
Holotype. Balteş (Citation1971, p. 13, pl. 2, fig. 2). Specimen L. C. 6220, microscope coordinates 48/110. Laboratory of Cretaceous and Tertiary Palaeontology Oil Geology Research Institute (Geological Institute of Romania), Bucharest, Romania. Present location unknown and effectively lost.
Neotype.
Plate 1, figures 13–16, sample B1, slide no. 4 (catalogue number: HGI-VB-1P-NAC-V-B4/4), England Finder coordinate Z38, embedded in silicone oil. Housed at the Department of Geology, Croatian Geological Survey.
Neotype locality. Našice Quarry, Vranović section, 45°27′10.69′′N, 18°2′4.12′′E, Našice, northern Croatia.
Emended diagnosis. Proximate dinoflagellate cyst with biconical outline, hornlike apical protuberance and smaller antapical horn. Gonyaulacacean tabulation is indicated by low sutural features. Triangular precingular 6″ having no contact with the apical plates. Wall surface granulate.
Emended description. Proximate dinoflagellate cyst with biconical outline and well-developed horn-like apical protuberance and much smaller antapical horn. The tips of the protuberances are hollow and rounded. The epi- and hypocyst are of similar size or the epicyst is larger. The apical horn is usually longer than the antapical structure. A standard gonyaulacacean S-type tabulation pattern is indicated by low solid ridges and sutural septa, most clearly seen in SEM images (Plate 1, figures 11–12) but also faintly discernible in well-preserved LM images (Plate 1, figures 5–10, 13–16). The sulcus is broad and the cingular margins are strongly offset, with the right side several cingulum widths below the left (, figure 11). The sutural septa are sometimes faintly developed and ridges might be discontinuous, indicated by rows of granules (Plate 1, figures 5–6). The precingular 6″ plate is triangular with the tip not in contact with the apical plates (Plate 1, figures 9–11, 13–15). The apical plate 4′ is longer than the 1′ plate (Plate 1, figures 9–11, 13–15). Expression of the apical tabulation may be strongly suppressed due to elongation of the hollow apical horn. The archeopyle is precingular, formed by loss of the 3″ plate (Plate 1, figures 1–3, 5, 7–8, 12, 16). The wall is single-layered, granulate on the outer surface and ∼1.1–1.3 µm thick.
Dimensions. The maximum length of the cyst body including the polar protuberances is 80 (93) 118 µm; the maximum equatorial width is 46 (52) 67 µm. The length of the apical horn ranges between 13 (18) 23 µm; the antapical horn is smaller, 4 (7) 9 µm. The neotype measurements are: length 87 µm, width 55 µm, length of apical horn 17 µm, antapical horn 7 µm. Twenty-three specimens were measured from the Našice, PAET 34P and PAET 27 materials. Dimensions of the Balteş (Citation1971) holotype material are length 45–70 µm, width 32–40 µm.
Comments and comparisions. The name Diconodinium inequicornutum was invalidly published by Balteş (Citation1971), and when Stover and Evitt (Citation1978) erected the species Pontiadinium inequicornutum, they designated the specimen illustrated in Balteş (Citation1971, p. 13, pl. 2, fig. 2) as the lectotype (in effect, the holotype). The holotype appears to be lost (S. Lőrincz pers. comm. 2021); therefore, we propose a neotype (, figures 13–16) in accordance with Art. 9.3 and Art. 9.11 of the Shenzen Code (Turland et al. Citation2018). The specimens illustrated in Balteş (Citation1971) are smaller (< 60 μm length) than the Lake Pannon specimens from Našice and the PAET cores (range 80–118 um). The median thickening reported by Balteş (Citation1971) and thickenings around the cingular area interpreted by Chen (Citation1982) are seen to be the flattened cingulum in LM images of the Lake Pannon specimens (, figures 1–8) and they clearly delimit the cingulum in SEM images (, figures 11–12). Low longitudinal thickenings reported by Balteş (Citation1971) most likely correspond to sutural ridges. However, the unclear photo images of Balteş do not allow definite resolution, leading Chen (Citation1982, p. 36) to conclude that the thickenings were subject to individual interpretation, and hence assignment to Komewuia. In contrast, the longitudinal thickenings in some Lake Pannon specimens (, figures 8–16) are clearly sutural ridges, a characteristic not present in Komewuia according to Chen (Citation1982, p. 36).
Now Komewuia. Originally Diconodinium (name not validly published), subsequently Pontiadinium, thirdly (and now) Komewuia. Baltes, 1971, included this species in the genus Diconodinium but failed to designate a holotype; therefore, according to I.C.B.N. Article 37, the name was not validly published. Stover and Evitt, 1978 designated as lectotype the specimen illustrated in Baltes, 1971. Since this taxon was validated by Stover and Evitt, 1978, Lentin and Williams, 1989 accepted the specimen illustrated in Baltes, 1971 as the holotype.
Holotype: Baltes, 1971, pl.2, fig.2 designated by Stover and Evitt, 1978, p.180 as Lectotype
Locus typicus: Romania
Stratum typicum: Early Pliocene
Original description: Baltes 1971, p. 5: Diconodinium inequicornutum
Test fusiform with straight or slightly concave edges, without tabulation. Epitract, larger than hypotract, is terminated by a single, cone-shaped, prominent horn, 10 to 15 µm long. Antapical part is likewise provided with a horn which is, however, shorter, cylindrical, with a rounded tip. Median part of the test, in the cingulum zone, shows a circular thickening of the outer membrane. In the epitract, having a precingular position, an archeopyle-like opening is visible. External membrane is smooth or finely stippled, and shows some longitudinal thickenings.
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Emended description Baranyi et al., 2022:
Holotype. Balteş (Citation1971, p. 13, pl. 2, fig. 2). Specimen L. C. 6220, microscope coordinates 48/110. Laboratory of Cretaceous and Tertiary Palaeontology Oil Geology Research Institute (Geological Institute of Romania), Bucharest, Romania. Present location unknown and effectively lost.
Neotype.
Plate 1, figures 13–16, sample B1, slide no. 4 (catalogue number: HGI-VB-1P-NAC-V-B4/4), England Finder coordinate Z38, embedded in silicone oil. Housed at the Department of Geology, Croatian Geological Survey.
Neotype locality. Našice Quarry, Vranović section, 45°27′10.69′′N, 18°2′4.12′′E, Našice, northern Croatia.
Emended diagnosis. Proximate dinoflagellate cyst with biconical outline, hornlike apical protuberance and smaller antapical horn. Gonyaulacacean tabulation is indicated by low sutural features. Triangular precingular 6″ having no contact with the apical plates. Wall surface granulate.
Emended description. Proximate dinoflagellate cyst with biconical outline and well-developed horn-like apical protuberance and much smaller antapical horn. The tips of the protuberances are hollow and rounded. The epi- and hypocyst are of similar size or the epicyst is larger. The apical horn is usually longer than the antapical structure. A standard gonyaulacacean S-type tabulation pattern is indicated by low solid ridges and sutural septa, most clearly seen in SEM images (Plate 1, figures 11–12) but also faintly discernible in well-preserved LM images (Plate 1, figures 5–10, 13–16). The sulcus is broad and the cingular margins are strongly offset, with the right side several cingulum widths below the left (, figure 11). The sutural septa are sometimes faintly developed and ridges might be discontinuous, indicated by rows of granules (Plate 1, figures 5–6). The precingular 6″ plate is triangular with the tip not in contact with the apical plates (Plate 1, figures 9–11, 13–15). The apical plate 4′ is longer than the 1′ plate (Plate 1, figures 9–11, 13–15). Expression of the apical tabulation may be strongly suppressed due to elongation of the hollow apical horn. The archeopyle is precingular, formed by loss of the 3″ plate (Plate 1, figures 1–3, 5, 7–8, 12, 16). The wall is single-layered, granulate on the outer surface and ∼1.1–1.3 µm thick.
Dimensions. The maximum length of the cyst body including the polar protuberances is 80 (93) 118 µm; the maximum equatorial width is 46 (52) 67 µm. The length of the apical horn ranges between 13 (18) 23 µm; the antapical horn is smaller, 4 (7) 9 µm. The neotype measurements are: length 87 µm, width 55 µm, length of apical horn 17 µm, antapical horn 7 µm. Twenty-three specimens were measured from the Našice, PAET 34P and PAET 27 materials. Dimensions of the Balteş (Citation1971) holotype material are length 45–70 µm, width 32–40 µm.
Comments and comparisions. The name Diconodinium inequicornutum was invalidly published by Balteş (Citation1971), and when Stover and Evitt (Citation1978) erected the species Pontiadinium inequicornutum, they designated the specimen illustrated in Balteş (Citation1971, p. 13, pl. 2, fig. 2) as the lectotype (in effect, the holotype). The holotype appears to be lost (S. Lőrincz pers. comm. 2021); therefore, we propose a neotype (, figures 13–16) in accordance with Art. 9.3 and Art. 9.11 of the Shenzen Code (Turland et al. Citation2018). The specimens illustrated in Balteş (Citation1971) are smaller (< 60 μm length) than the Lake Pannon specimens from Našice and the PAET cores (range 80–118 um). The median thickening reported by Balteş (Citation1971) and thickenings around the cingular area interpreted by Chen (Citation1982) are seen to be the flattened cingulum in LM images of the Lake Pannon specimens (, figures 1–8) and they clearly delimit the cingulum in SEM images (, figures 11–12). Low longitudinal thickenings reported by Balteş (Citation1971) most likely correspond to sutural ridges. However, the unclear photo images of Balteş do not allow definite resolution, leading Chen (Citation1982, p. 36) to conclude that the thickenings were subject to individual interpretation, and hence assignment to Komewuia. In contrast, the longitudinal thickenings in some Lake Pannon specimens (, figures 8–16) are clearly sutural ridges, a characteristic not present in Komewuia according to Chen (Citation1982, p. 36).