Back
Operculodinium longispinigerum
Operculodinium longispinigerum Matsuoka, 1983
Holotype: Matsuoka, 1983, pl.9, figs.8a-b
Locus typicus: Haizume, Nishiyama-cho, Niigata Prefecture, Central Japan.
Stratum typicum: Nishiyama Formation - Pliocene or younger
--------------------------------------------------
Original diagnosis: Matsuoka 1983, p. 125: Operculodinium longispinegerum
Small cyst with smooth or finely granular surface, and spherical in shape. Processes relatively long, solid or slender, and nontabular. Distal extremities acuminate or occasionally bifid. Precingular archeopyle simple. Operculum completely free.
Original description: Matsuoka 1983, p. 125: Operculodinium longispinegerum
The chorate cyst is small and spherical in shape, and consists of two layers, periphragm and endophragm adpressed between processes. Apparently nontabular processes are relatively long, slender sometimes solid or flexible and sparsely distributed. The surface of the process stalks is smooth and distal extremities are acuminate or minutely bifid, but sometimes furcate (pl. 9, figs. 5, 6). The paracingulum and parasulcus are not indicated by any ornamentation. The archeopyle is a simple precingular type possibly made up of displacement of the 3" paraplate.
Dimensions: Holotype: Cyst diameter 36 Ám, length of processes 7.0-8.6 Ám. Other specimens: Cyst diameter 29-40Ám, length of processes 7.0-14.0 Ám. Number of specimens measured: 11.
Occurrence: Rare to several in the Teradomari Formation, Shiiya Formation, Nishiyama Formation and its equivalent formations, and Haizume Formation and its equivalent formation (Late Miocene to Early Pleistocene).
Remarks: Matsuoka 1983, p. 125
Operculodinium longispinigerum sp. nov. is closely similar to O. centrocarpum (DEFLANDRE &
COOKSON) in general shape, but differs from the latter in possessing the processes with acuminate or bifid rather than capitate distal extremities and their sparse distribution.
---------------------------------------------------
Supplemental description: McMinn, 1992, p.435
Small, smooth-walled cyst having slender, solid, nontabular, accuminate processes. Wall consists of an autophragm only and is smooth between processes. Archaeopyle is precingular, type 1P with a free operculum, and no other paratabulation is indicated.
Holotype: Matsuoka, 1983, pl.9, figs.8a-b
Locus typicus: Haizume, Nishiyama-cho, Niigata Prefecture, Central Japan.
Stratum typicum: Nishiyama Formation - Pliocene or younger
--------------------------------------------------
Original diagnosis: Matsuoka 1983, p. 125: Operculodinium longispinegerum
Small cyst with smooth or finely granular surface, and spherical in shape. Processes relatively long, solid or slender, and nontabular. Distal extremities acuminate or occasionally bifid. Precingular archeopyle simple. Operculum completely free.
Original description: Matsuoka 1983, p. 125: Operculodinium longispinegerum
The chorate cyst is small and spherical in shape, and consists of two layers, periphragm and endophragm adpressed between processes. Apparently nontabular processes are relatively long, slender sometimes solid or flexible and sparsely distributed. The surface of the process stalks is smooth and distal extremities are acuminate or minutely bifid, but sometimes furcate (pl. 9, figs. 5, 6). The paracingulum and parasulcus are not indicated by any ornamentation. The archeopyle is a simple precingular type possibly made up of displacement of the 3" paraplate.
Dimensions: Holotype: Cyst diameter 36 Ám, length of processes 7.0-8.6 Ám. Other specimens: Cyst diameter 29-40Ám, length of processes 7.0-14.0 Ám. Number of specimens measured: 11.
Occurrence: Rare to several in the Teradomari Formation, Shiiya Formation, Nishiyama Formation and its equivalent formations, and Haizume Formation and its equivalent formation (Late Miocene to Early Pleistocene).
Remarks: Matsuoka 1983, p. 125
Operculodinium longispinigerum sp. nov. is closely similar to O. centrocarpum (DEFLANDRE &
COOKSON) in general shape, but differs from the latter in possessing the processes with acuminate or bifid rather than capitate distal extremities and their sparse distribution.
---------------------------------------------------
Supplemental description: McMinn, 1992, p.435
Small, smooth-walled cyst having slender, solid, nontabular, accuminate processes. Wall consists of an autophragm only and is smooth between processes. Archaeopyle is precingular, type 1P with a free operculum, and no other paratabulation is indicated.