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Laciniadinium petaloidum
From Fensome et al., 2019:
Laciniadinium petaloidum Vasilyeva in Andreeva-Grigorovich et al., 2011, p.35–36, pl.9, figs.1–7; text-fig.17a–c. Holotype:
Andreeva-Grigorovich et al., 2011, pl.9, fig.5; text-fig.17c. Vasilyeva in Andreeva-Grigorovich et al. (2011, p 36) cited the holotype as "pl.9, figs.1–7 and text-fig.17c". This holotype citation includes multiple specimens. However, in the caption to text-fig.17, the holotype is clearly indicated as the far right of three figures (here cited as text-fig.17c), which is also figured as pl.9, fig.5. Age: Danian–Selandian.
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Original description: [Andreeva-Grigorovich et al., 2011] (translated from Russian):
Laciniadinium petaloidum Vassilyeva sp. nov. Table IX, 1-7; fig. 17
Name. From Latin petale.
Diagnosis. Peridinioid proximate cysts are of intermediate size without apical horn. Antapical horns present, slightly prominent, rounded, equal or left horn more than right one. Lateral horns absent. Cingulum is not expressed or visible as low ridges. Periphragm thin, smooth or slightly granulated. Periarcheopyle of combined type, intercalary-precingular, type tI3Pa (fig. 17). Operculum usually attached at cingulum side.
Description. The pericyst is rounded-oval or oval-pentagonal. The apical horn is absent; the apical part of the cyst is rounded. The antapical horns are slightly marked by smooth symmetrical arcs or the left horn protrudes slightly more. The periphragm is thin, smooth or finely granular, sometimes slightly wrinkled. The endocyst repeats the shape of the pericyst. The endophragm is thin, tightly adjoining the periphragm so that it is visible as a separate layer only in the apical part of the cyst, where a small epicoel is located. Signs of paratabulation are represented only by the periarchaeopile and paracingulum. The paracingulum is expressed by an uneven, slightly sagging groove, sometimes not distinguishable at all. The periarchaeopile is large, hexagonal, type t3IPa (Fig. 17). The operculum is attached along the cingular side or free. The parasulcus is not visible or is visible as a wide arcuate fold on the ventral side of the cyst. Drop-shaped inclusions of organic material (an "eye") are usually noted in the cingulate-sulcate zone.
Holotype. Plate IX, 1-7; Fig. 17, c. Prep. NU-59-1.
Location. Novouzenskaya reference well, Lower Syzran subsuite, sample 59 (Northern Caspian region).
Dimensions (µm). Holotype: Length and width of pericyst 39.6; height of archeopyle - 9.9; width of archeopyle 16.5. Another specimen (Fig. 17, 1): length and width of pericyst 41.3; height of archeopyle 9.4; width of archeopyle 14.2.
Comparison. Differs from Laciniadinium williamsii Ioannides, 1986 in wider proportions and the absence of apical and antapical horns. Close in form to the species L. granulatum He Chengquan, 1991, but the latter has a clearly expressed granular periphragm and a cingulum marked by a double fold. In addition, the stratigraphic distribution of L. granulatum is different: Turonian - Upper Senonian. Morphologically similar to L. minutum He Chengquan, 1984, but the latter has a distinct cingulum, wrinkled periphragm and is distributed in Upper Cretaceous deposits. Differs from the species L. subtile He Chengquan, 1991 in a smoother and more rounded shape of the pericyst.
Notes. The cyst has a characteristic broadly oval, petal-like shape. The hypocyst shape varies: the antapical projections may be slightly asymmetrical or identical, but are not pointed. An arc-shaped fold is often observed between the antapical projections. The morphological features that indicate paracingulum vary and are sometimes not apparent at all.
Distribution. Russia, Northern Caspian region, upper part of the Tsiganovskaya suite, Syzran suite; Trans-Urals, Talitskaya suite. Paleocene, Upper Danian, Zealandian.
Laciniadinium petaloidum Vasilyeva in Andreeva-Grigorovich et al., 2011, p.35–36, pl.9, figs.1–7; text-fig.17a–c. Holotype:
Andreeva-Grigorovich et al., 2011, pl.9, fig.5; text-fig.17c. Vasilyeva in Andreeva-Grigorovich et al. (2011, p 36) cited the holotype as "pl.9, figs.1–7 and text-fig.17c". This holotype citation includes multiple specimens. However, in the caption to text-fig.17, the holotype is clearly indicated as the far right of three figures (here cited as text-fig.17c), which is also figured as pl.9, fig.5. Age: Danian–Selandian.
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Original description: [Andreeva-Grigorovich et al., 2011] (translated from Russian):
Laciniadinium petaloidum Vassilyeva sp. nov. Table IX, 1-7; fig. 17
Name. From Latin petale.
Diagnosis. Peridinioid proximate cysts are of intermediate size without apical horn. Antapical horns present, slightly prominent, rounded, equal or left horn more than right one. Lateral horns absent. Cingulum is not expressed or visible as low ridges. Periphragm thin, smooth or slightly granulated. Periarcheopyle of combined type, intercalary-precingular, type tI3Pa (fig. 17). Operculum usually attached at cingulum side.
Description. The pericyst is rounded-oval or oval-pentagonal. The apical horn is absent; the apical part of the cyst is rounded. The antapical horns are slightly marked by smooth symmetrical arcs or the left horn protrudes slightly more. The periphragm is thin, smooth or finely granular, sometimes slightly wrinkled. The endocyst repeats the shape of the pericyst. The endophragm is thin, tightly adjoining the periphragm so that it is visible as a separate layer only in the apical part of the cyst, where a small epicoel is located. Signs of paratabulation are represented only by the periarchaeopile and paracingulum. The paracingulum is expressed by an uneven, slightly sagging groove, sometimes not distinguishable at all. The periarchaeopile is large, hexagonal, type t3IPa (Fig. 17). The operculum is attached along the cingular side or free. The parasulcus is not visible or is visible as a wide arcuate fold on the ventral side of the cyst. Drop-shaped inclusions of organic material (an "eye") are usually noted in the cingulate-sulcate zone.
Holotype. Plate IX, 1-7; Fig. 17, c. Prep. NU-59-1.
Location. Novouzenskaya reference well, Lower Syzran subsuite, sample 59 (Northern Caspian region).
Dimensions (µm). Holotype: Length and width of pericyst 39.6; height of archeopyle - 9.9; width of archeopyle 16.5. Another specimen (Fig. 17, 1): length and width of pericyst 41.3; height of archeopyle 9.4; width of archeopyle 14.2.
Comparison. Differs from Laciniadinium williamsii Ioannides, 1986 in wider proportions and the absence of apical and antapical horns. Close in form to the species L. granulatum He Chengquan, 1991, but the latter has a clearly expressed granular periphragm and a cingulum marked by a double fold. In addition, the stratigraphic distribution of L. granulatum is different: Turonian - Upper Senonian. Morphologically similar to L. minutum He Chengquan, 1984, but the latter has a distinct cingulum, wrinkled periphragm and is distributed in Upper Cretaceous deposits. Differs from the species L. subtile He Chengquan, 1991 in a smoother and more rounded shape of the pericyst.
Notes. The cyst has a characteristic broadly oval, petal-like shape. The hypocyst shape varies: the antapical projections may be slightly asymmetrical or identical, but are not pointed. An arc-shaped fold is often observed between the antapical projections. The morphological features that indicate paracingulum vary and are sometimes not apparent at all.
Distribution. Russia, Northern Caspian region, upper part of the Tsiganovskaya suite, Syzran suite; Trans-Urals, Talitskaya suite. Paleocene, Upper Danian, Zealandian.