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Cristadinium lucyae
Cristadinium lucyae sp. nov., Cárdenas et al., 2021
Holotype: Cárdenas et al. 2021, Plate I, 1–4
Type locality: Cocinetas Basin, La Guajira, Colombia; Stratigraphic horizon: Uitpa Formation
Age: Aquitanian, early Miocene
Original description: Cárdenas et al., 2021:
Diagnosis:
Peridinioid cyst weakly dorsoventrally compressed, proximate, acavate. Outline pentagonal in dorsoventral view, straight to slightly convex epicyst with reduced apical horn, straight to slightly concave hypocyst with two small antapical horns. Autophragm smooth with scattered solid ornamentation forming interrupted low sutural crests. Spinules tapered to truncated. Cingulum planar to slightly helicoidal bearing continuous crests along the anterior margin. Archeopyle intercalary hexa 2a, presumably isodeltalinteloid. Operculum free to adherent.
Description:
Peridinioid cyst proximate, acavate and weakly dorsoventrally compressed with pentagonal outline in dorsoventral view: sides of the epicyst are straight to slightly convex, whereas sides of the hypocyst are straight to slightly concave; length of the epicyst and the hypocyst are approximately equal.
Wall: single-layered (autophragm), ~ 0.4 μm thick and light brown. The autophragm is smooth and sparsely ornamented with isolated sutural spinules usually forming interrupted low crests. Spinules are solid, generally ~ 2.0 μm long (few up to ~ 3.5 μm), and with broad bases and tapered to truncated tips. Linear crests with distinctively thickened bases incompletely reflect tabulation. Crests are well-developed on the apex, antapical horns, cingulum and sometimes along most of both lateral margins. The apex often bears ornamentation. The apical horn is faintly developed by a thickening of the apex. Antapical horns are similar in length, slightly divergent and up to ~6.5 μm long. The antapical depression is shallow and wide. The cingulum is planar to slightly helicoidal, indicated by two folds and interrupted ventrally by an unornamented sulcal region. The cingular area, which is sometimes inflated, bears ornamentation from single spinules to continuous crests. The cingular ornamentation is evenly distributed along the anterior margin but unevenly distributed along the posterior margin, presumably reflecting tabulation. Cysts are weakly dorsoventrally compressed and 21 of the 57 specimens found are in polar orientation presumably due to post-depositional compression (Plate I, 10–16).
Archeopyle: hexagonal, formed by the release of the anterior intercalary plate 2a, and presumably isodeltalinteloid (Plate I, 7–9)
Operculum: free and sometimes adherent on adcingular margin.
Dimensions:
Holotype: length, 52 μm; width, 56 μm.
Range: length, 42–63 μm; width, 44–68 μm
Fifteen specimens measured.
Affinities/Comparison:
Cristadinium lucyae sp. nov. is distinguished from previously described Cristadinium species in having solid sutural spinules unevenly distributed over the entire cyst, which may be distally tapered to truncated, forming linear low crests with thickened bases and distally indented to serrated (Fig. 4). C. cristatoserratum has a continuous sutural crests converging towards the apex and lacking scattered
spines on the epicyst. C. diminutivum is smaller (~ 41 μm) and has angular outline. C. headii has distally acicular to bifid processes, and C. striatiserratum has nontabular striations. Single specimens reported as C. aff. cristatoserratum from the late Miocene of the Labrador Sea (pl. VII, 12, Head et al., 1989), Cristadinium sp. 1 (pl. VII, 9, Head et al., 1989) and Cristadinium sp. 2 (pl. VII, 10, Head et al., 1989) may belong to C. lucyae sp. nov. Mertens et al. (2017) interpreted as Trinovantedinium pallidifulvum the specimen depicted in de Verteuil and Norris (1992; pl. II, 9–12) as
an undefined protoperidiniacean. However, we consider that this specimen belongs to Cristadinium lucyae sp. nov. While T. pallidifulvum is characterized by acuminate penitabular and intratabular ornamentation (Matsuoka, 1987; de Verteuil and Norris, 1992; Mertens et al., 2017), de Verteuil and Norris (1992) reported sutural spinules, which are a key trait of C. lucyae sp. nov. Furthermore, the photomicrographs in de Verteuil and Norris (1992) and Edwards et al. (2018) show distally tapered and truncated (rarely branched) ornamentation, which are connected proximally, forming low crests especially along the lateral margins and the cingulum (see de Verteuil and Norris, 1992, p. 404–405; Edwards et al., 2018, p. 188–189).
Holotype: Cárdenas et al. 2021, Plate I, 1–4
Type locality: Cocinetas Basin, La Guajira, Colombia; Stratigraphic horizon: Uitpa Formation
Age: Aquitanian, early Miocene
Original description: Cárdenas et al., 2021:
Diagnosis:
Peridinioid cyst weakly dorsoventrally compressed, proximate, acavate. Outline pentagonal in dorsoventral view, straight to slightly convex epicyst with reduced apical horn, straight to slightly concave hypocyst with two small antapical horns. Autophragm smooth with scattered solid ornamentation forming interrupted low sutural crests. Spinules tapered to truncated. Cingulum planar to slightly helicoidal bearing continuous crests along the anterior margin. Archeopyle intercalary hexa 2a, presumably isodeltalinteloid. Operculum free to adherent.
Description:
Peridinioid cyst proximate, acavate and weakly dorsoventrally compressed with pentagonal outline in dorsoventral view: sides of the epicyst are straight to slightly convex, whereas sides of the hypocyst are straight to slightly concave; length of the epicyst and the hypocyst are approximately equal.
Wall: single-layered (autophragm), ~ 0.4 μm thick and light brown. The autophragm is smooth and sparsely ornamented with isolated sutural spinules usually forming interrupted low crests. Spinules are solid, generally ~ 2.0 μm long (few up to ~ 3.5 μm), and with broad bases and tapered to truncated tips. Linear crests with distinctively thickened bases incompletely reflect tabulation. Crests are well-developed on the apex, antapical horns, cingulum and sometimes along most of both lateral margins. The apex often bears ornamentation. The apical horn is faintly developed by a thickening of the apex. Antapical horns are similar in length, slightly divergent and up to ~6.5 μm long. The antapical depression is shallow and wide. The cingulum is planar to slightly helicoidal, indicated by two folds and interrupted ventrally by an unornamented sulcal region. The cingular area, which is sometimes inflated, bears ornamentation from single spinules to continuous crests. The cingular ornamentation is evenly distributed along the anterior margin but unevenly distributed along the posterior margin, presumably reflecting tabulation. Cysts are weakly dorsoventrally compressed and 21 of the 57 specimens found are in polar orientation presumably due to post-depositional compression (Plate I, 10–16).
Archeopyle: hexagonal, formed by the release of the anterior intercalary plate 2a, and presumably isodeltalinteloid (Plate I, 7–9)
Operculum: free and sometimes adherent on adcingular margin.
Dimensions:
Holotype: length, 52 μm; width, 56 μm.
Range: length, 42–63 μm; width, 44–68 μm
Fifteen specimens measured.
Affinities/Comparison:
Cristadinium lucyae sp. nov. is distinguished from previously described Cristadinium species in having solid sutural spinules unevenly distributed over the entire cyst, which may be distally tapered to truncated, forming linear low crests with thickened bases and distally indented to serrated (Fig. 4). C. cristatoserratum has a continuous sutural crests converging towards the apex and lacking scattered
spines on the epicyst. C. diminutivum is smaller (~ 41 μm) and has angular outline. C. headii has distally acicular to bifid processes, and C. striatiserratum has nontabular striations. Single specimens reported as C. aff. cristatoserratum from the late Miocene of the Labrador Sea (pl. VII, 12, Head et al., 1989), Cristadinium sp. 1 (pl. VII, 9, Head et al., 1989) and Cristadinium sp. 2 (pl. VII, 10, Head et al., 1989) may belong to C. lucyae sp. nov. Mertens et al. (2017) interpreted as Trinovantedinium pallidifulvum the specimen depicted in de Verteuil and Norris (1992; pl. II, 9–12) as
an undefined protoperidiniacean. However, we consider that this specimen belongs to Cristadinium lucyae sp. nov. While T. pallidifulvum is characterized by acuminate penitabular and intratabular ornamentation (Matsuoka, 1987; de Verteuil and Norris, 1992; Mertens et al., 2017), de Verteuil and Norris (1992) reported sutural spinules, which are a key trait of C. lucyae sp. nov. Furthermore, the photomicrographs in de Verteuil and Norris (1992) and Edwards et al. (2018) show distally tapered and truncated (rarely branched) ornamentation, which are connected proximally, forming low crests especially along the lateral margins and the cingulum (see de Verteuil and Norris, 1992, p. 404–405; Edwards et al., 2018, p. 188–189).