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Operculodinium tegillatum
Operculodinium tegillatum Head, 1997, p.180,183, fig.9, nos.13–20; fig.10; fig.11, nos.1–2; fig.16, nos.13–16; fig.17, no.1.
Taxonomic junior synonyms: Operculodinium antwerpense, according to Louwye and de Schepper (2010, p.767); Operculodinium? pontis (name not validly published), a taxonomic junior synonym of Operculodinium antwerpense according to Louwye (1999, p.115).
Holotype: Head, 1997, fig.9, nos.13–17.
Age: middle Pliocene.
Original descritpion (Head, 1997):
Operculodinium tegillatum new speices
Columellate/tegillate morphotype of Operculodinium centrocarpum sensu Wall and Dale, 1968. Head, 1994a, pl. 11, figs. 14, 15.
Diagnosis: A small to medium species of Operculodinium whose wall consists of thin, solid pedium and a reticulate or perforate tegillum of similar thickness supported by narrow columellae. Processes are non-tabular to intratabular, composed of tegillum, and have smooth outer surface . Bases are hollow and expanded, distal processes tips are closed and expanded into small platforms usually with irregular margins and fairly rounded angles; operculum free.
Description: Cysts skolochorate with spherical central body bearing numerous non-tabula processes. Wall about 0.5 µm thick, consist of thin, solid pedium (less than 0.2 mm) and reticulate or perforate tectum of similar thickness supported by columellae of about 0.3 µm or less in diameter, spaced about 0.5 – 1.0 µm apart. Columellae occur between processes and beneath process bases.
Comparison. —No other species of Operculodinium is known to have a tegillate/columellate wall structure.
Dimensions. —Holotype: central body equatorial diameter, 35 µm; average process length, 7 µm. Range: central body maximum diameter, 25(32.9)45 µm, standard deviation, 3.16; average process length, 3.5(6.2)9 µm, standard deviation, 0.96. One hundred and two specimens were measured. See also Figure 10.
Etymology. —Latin tegillum, small roof; with reference to the tegillate nature of the wall structure that characterizes this species.
Holotype. —Figure 9.13-9.17. Sample NQ2, slide 1; England Finder reference N31/0. ROM 52493.
Type stratum and locality. —Ramsholt Member of the Cor¬alline Crag Formation at Rockhall Wood, Suffolk.
Occurrence. — Known only from the mid Pliocene of eastern England (this study).
Taxonomic junior synonyms: Operculodinium antwerpense, according to Louwye and de Schepper (2010, p.767); Operculodinium? pontis (name not validly published), a taxonomic junior synonym of Operculodinium antwerpense according to Louwye (1999, p.115).
Holotype: Head, 1997, fig.9, nos.13–17.
Age: middle Pliocene.
Original descritpion (Head, 1997):
Operculodinium tegillatum new speices
Columellate/tegillate morphotype of Operculodinium centrocarpum sensu Wall and Dale, 1968. Head, 1994a, pl. 11, figs. 14, 15.
Diagnosis: A small to medium species of Operculodinium whose wall consists of thin, solid pedium and a reticulate or perforate tegillum of similar thickness supported by narrow columellae. Processes are non-tabular to intratabular, composed of tegillum, and have smooth outer surface . Bases are hollow and expanded, distal processes tips are closed and expanded into small platforms usually with irregular margins and fairly rounded angles; operculum free.
Description: Cysts skolochorate with spherical central body bearing numerous non-tabula processes. Wall about 0.5 µm thick, consist of thin, solid pedium (less than 0.2 mm) and reticulate or perforate tectum of similar thickness supported by columellae of about 0.3 µm or less in diameter, spaced about 0.5 – 1.0 µm apart. Columellae occur between processes and beneath process bases.
Comparison. —No other species of Operculodinium is known to have a tegillate/columellate wall structure.
Dimensions. —Holotype: central body equatorial diameter, 35 µm; average process length, 7 µm. Range: central body maximum diameter, 25(32.9)45 µm, standard deviation, 3.16; average process length, 3.5(6.2)9 µm, standard deviation, 0.96. One hundred and two specimens were measured. See also Figure 10.
Etymology. —Latin tegillum, small roof; with reference to the tegillate nature of the wall structure that characterizes this species.
Holotype. —Figure 9.13-9.17. Sample NQ2, slide 1; England Finder reference N31/0. ROM 52493.
Type stratum and locality. —Ramsholt Member of the Cor¬alline Crag Formation at Rockhall Wood, Suffolk.
Occurrence. — Known only from the mid Pliocene of eastern England (this study).