Back
Atlanticodinium
Atlanticodinium, Head and Mantilla-Duran, 2020
Type species: Atlanticodinium striaticonulum, Head and Mantilla-Duran, 2020 (Plate 1, figs. 1–9)
Age: Middle Pleistocene
Location: central North Atlantic Ocean
Stratigraphic range: early Eocene (as A. janduchenei; see Bijl et al., 2018) to the present (A. striaticonulum is extant).
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Head and Mantilla-Duran, 2020]:
Diagnosis:
Small- to medium-sized proximate cysts with spherical to subspherical central body. Wall nonfibrous, surface smooth to finely ornamented, bearing numerous, short, hollow, unbranched, nontabular, nonfibrous processes. An apical protuberance may be present.
Archeopyle precingular, margin with well-defined angles; operculum free.
Affinities:
The holotype of Operculodinium centrocarpum, the type of the genus Operculodinium Wall, 1967 from the Middle Miocene of Australia (Deflandre and Cookson, 1955), has a central body with a fibrous surface (Matsuoka et al., 1997), an archeopyle margin with rounded angles, and a process distribution that is probably intratabular.
A full review of Operculodinium is overdue given that many species presently assigned to this genus lack some or all of these important characteristics. Lingulodinium machaerophorum (Deflandre and Cookson, 1955) Wall, 1967, the holotype of which serves as the type of the genus Lingulodinium Wall, 1967 from the Middle Miocene of Australia, has an archeopyle margin with rounded angles. The type of Cerebrocysta Bujak in Bujak et al., 1980, from the Eocene of southern England, and that of Pyxidinopsis Habib, 1976, from the Berriasian–Hauterivian of the western North Atlantic Ocean, both have precingular archeopyles but lack processes. Reviews of these genera are likewise needed. The type of Pyxidiella Cookson and Eisenack, 1958, from the Upper Jurassic of Western Australia, has an anterior intercalary archeopyle and similarly lacks processes.
Type species: Atlanticodinium striaticonulum, Head and Mantilla-Duran, 2020 (Plate 1, figs. 1–9)
Age: Middle Pleistocene
Location: central North Atlantic Ocean
Stratigraphic range: early Eocene (as A. janduchenei; see Bijl et al., 2018) to the present (A. striaticonulum is extant).
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Head and Mantilla-Duran, 2020]:
Diagnosis:
Small- to medium-sized proximate cysts with spherical to subspherical central body. Wall nonfibrous, surface smooth to finely ornamented, bearing numerous, short, hollow, unbranched, nontabular, nonfibrous processes. An apical protuberance may be present.
Archeopyle precingular, margin with well-defined angles; operculum free.
Affinities:
The holotype of Operculodinium centrocarpum, the type of the genus Operculodinium Wall, 1967 from the Middle Miocene of Australia (Deflandre and Cookson, 1955), has a central body with a fibrous surface (Matsuoka et al., 1997), an archeopyle margin with rounded angles, and a process distribution that is probably intratabular.
A full review of Operculodinium is overdue given that many species presently assigned to this genus lack some or all of these important characteristics. Lingulodinium machaerophorum (Deflandre and Cookson, 1955) Wall, 1967, the holotype of which serves as the type of the genus Lingulodinium Wall, 1967 from the Middle Miocene of Australia, has an archeopyle margin with rounded angles. The type of Cerebrocysta Bujak in Bujak et al., 1980, from the Eocene of southern England, and that of Pyxidinopsis Habib, 1976, from the Berriasian–Hauterivian of the western North Atlantic Ocean, both have precingular archeopyles but lack processes. Reviews of these genera are likewise needed. The type of Pyxidiella Cookson and Eisenack, 1958, from the Upper Jurassic of Western Australia, has an anterior intercalary archeopyle and similarly lacks processes.