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Operculodinium wallii
Operculodinium wallii Matsuoka, 1983
Head in Head and Wrenn (1992, p.24) considered this species to be a possible taxonomic junior synonym of Operculodinium centrocarpum.
Holotype: Matsuoka, 1983, pl.9, figs.1a-b
Locus typicus: Haizume, Nishiyama-cho, Niigata Prefecture, Central Japan.
Stratum typicum: Nishiyama Formation - Pliocene or younger.
Age: Pliocene or younger
Original diagnosis: Matsuoka 1983, p. 127: Operculodinium wallii
Cyst intermediate and subspherical to ovoidal. Surface of cyst minutely reticulate. Processes nontabular and flexible. Their extremities recurved and bifid. Archeopyle simple precingular. Operculum completely free.
Description: Matsuoka 1983, p. 127: Operculodinium wallii
The intermediate chorate cyst is subspherical to ovoidal in shape, and consists of two layers, periphragm and endophragm adpressed between processes. The surface of the periphragm shows minute reticulation. The processes are apparently nontabular, very slender, hollow, flexible and are sparsely distributed. The length of processes is uniform within a single specimen. At the proximal base of the processes, arched openings are often observed. Their distal parts are bifid, and the final branches recurve outwards. The archeopyle is a simple precingular type formed by loss of the 3" paraplate.
Dimensions: Holotype; Cyst diameter 74 Ám x 74 Ám, length of processes 15.5-19Ám. Other specimens: Cyst diameter 50-76Ám x 50-76 Ám, length of processes 12.0-20.7 Ám. Number of specimens measured: 10.
Occurrence: Rare to few in the Teradomari Formation, Nishiyama Formation and its equivalent formations, and Haizume Formation and its equivalent formation (Late Miocene to Early Pleistocene).
Remarks: Matsuoka 1983, p. 127
This new species differs from Operculodinium centrocarpum (DEFLANDRE & COOKSON) in having a larger cyst body and longer processes with recurved bifid distal extremities and in possessing sparsely distributed processes. This species is also different from O. crassum and O. israelianum (ROSSIGNOL) in having slender and flexible processes.
Head in Head and Wrenn (1992, p.24) considered this species to be a possible taxonomic junior synonym of Operculodinium centrocarpum.
Holotype: Matsuoka, 1983, pl.9, figs.1a-b
Locus typicus: Haizume, Nishiyama-cho, Niigata Prefecture, Central Japan.
Stratum typicum: Nishiyama Formation - Pliocene or younger.
Age: Pliocene or younger
Original diagnosis: Matsuoka 1983, p. 127: Operculodinium wallii
Cyst intermediate and subspherical to ovoidal. Surface of cyst minutely reticulate. Processes nontabular and flexible. Their extremities recurved and bifid. Archeopyle simple precingular. Operculum completely free.
Description: Matsuoka 1983, p. 127: Operculodinium wallii
The intermediate chorate cyst is subspherical to ovoidal in shape, and consists of two layers, periphragm and endophragm adpressed between processes. The surface of the periphragm shows minute reticulation. The processes are apparently nontabular, very slender, hollow, flexible and are sparsely distributed. The length of processes is uniform within a single specimen. At the proximal base of the processes, arched openings are often observed. Their distal parts are bifid, and the final branches recurve outwards. The archeopyle is a simple precingular type formed by loss of the 3" paraplate.
Dimensions: Holotype; Cyst diameter 74 Ám x 74 Ám, length of processes 15.5-19Ám. Other specimens: Cyst diameter 50-76Ám x 50-76 Ám, length of processes 12.0-20.7 Ám. Number of specimens measured: 10.
Occurrence: Rare to few in the Teradomari Formation, Nishiyama Formation and its equivalent formations, and Haizume Formation and its equivalent formation (Late Miocene to Early Pleistocene).
Remarks: Matsuoka 1983, p. 127
This new species differs from Operculodinium centrocarpum (DEFLANDRE & COOKSON) in having a larger cyst body and longer processes with recurved bifid distal extremities and in possessing sparsely distributed processes. This species is also different from O. crassum and O. israelianum (ROSSIGNOL) in having slender and flexible processes.