Back
Spinidinium
From Williams et al., 2017:
[Spinidinium, Cookson and Eisenack, 1962b, p. 489; Emendations: Lentin and Williams, 1976, p. 62–63; Quattrocchio and Sarjeant, 2003, p. 134–135; Sluijs et al., 2009, p. 46.
Type species: Spinidinium styloniferum, Cookson and Eisenack, 1962 (pl.1, figs.1–2)]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Cookson and Eisenack, 1962]:
Description:
Shell longer than broad, concavo-convex, with straight or slightly convex slanting sides. Epitheca horned, hypotheca with a small projection on one side. Girdle equatorial, circular; longitudinal furrow more or less well developed. Wall of the shell two-layered, the outer layer which is covered with small spines, forming the apical horn and antapical projection. A pylome may develop on the dorsal surface of the epitheca.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description:
Lentin and Williams 1976:
Description:
Other genera within the fossil peridinioid group possessing penitabular echinae or processes are Chatangiella, Ginginodinium and Kisselovia. Chatangiella differs from Spinidinium in having an easily discernible endocyst, well developed apical and antapical pericoels, a hepta/pentapartite pericingulum, and an omegaform hexa 2a archeopyle. Ginginodinium has an intercalary archeopyle in which all three intercalaries are removed, or a combination archeopyle in which all three intercalaries are removed, accessory archeopyle sutures tend to be developed between precingulars 2``-3``, 3``-4``, 4``-5`` and 5``-6``. Kisselovia has lateral horns and a quadra intercalary archeopyle resulting from the loss of the second anterior paraplate 2a.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Evitt 1978, p. 124-125:
Synopsis:
Cysts proximochorate, cornucavate or circumcavate, compressed peridinioid to nearly lenticular with an apical horn, an usually well-developed left antapical horn and a reduced right antapical horn; paratabulation peridiniacean, hexa style, indicated on periphragm by intratabular or penitabular ornamentation; smooth pandasuturate areas commonly discernible; archeopyle intercalary, Type I or Ia; archeopyle index <0.5.
Description:
Shape: Compressed peridinioid to nearly lenticular, with an apical horn and a generally well-developed left antapical horn; right antapical horn commonly reduced or absent.
Wall relationships: Cysts generally cornucavate, rarely circumcavate.
Wall features: No parasutural features. Periphragm ornamented with widely to closely spaced cones, spinules, or spines arranged in penitabular rows or intratabular clusters, and commonly separated by smooth, pandasuturate areas; endophragm smooth, usually thin.
Paratabulation: Indicated by penitabular and intratabular features in conjunction with pandasuturate areas; paratabulation peridiniacean, hexa style, formula: ?`, 3a, 7``, Xc, 5```, 2````.
Archeopyle: Intercalary, Type I or Ia (2a only); archeopyle index <0.5; operculum free or attached antapically.
Paracingulum: Indicated in equatorial area by transverse alignment of ornamentation into two parallel rows that commonly delimit a shallow to moderately deep concavity.
Parasulcus: Generally poorly expressed by a shallow depression, mainly on the hypocyst, and by the absence of ornamentation.
Size: Small to intermediate.
Affinities:
Spinidinium differs from Vozzhenikovia in having the ornamentation arranged in penitabular rows or intratabular clusters, or both, rather than being nontabular; and from Ginginodinium in having a Type I rather than a Type 3I intercalary archeopyle.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Spinidinium Cookson and Eisenack, 1962b, emend. Lentin and Williams, 1976. Synopsis from Stover and Evitt (1978, p.124), Cysts proximochorate, cornucavate or circumcavate, compressed peridinioid to nearly lenticular with an apical horn, an unusually well-developed left antapical horn and a reduced right antapical horn; paratabulation peridiniacean, hexa style, indicated on periphragm by intratabular or penitabular ornamentation; smooth pandasuturate areas commonly discernible; archeopyle intercalary, type I or Ia, archeopyle index <0.5. The archeopyle is steno-deltaform.
[Spinidinium, Cookson and Eisenack, 1962b, p. 489; Emendations: Lentin and Williams, 1976, p. 62–63; Quattrocchio and Sarjeant, 2003, p. 134–135; Sluijs et al., 2009, p. 46.
Type species: Spinidinium styloniferum, Cookson and Eisenack, 1962 (pl.1, figs.1–2)]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Cookson and Eisenack, 1962]:
Description:
Shell longer than broad, concavo-convex, with straight or slightly convex slanting sides. Epitheca horned, hypotheca with a small projection on one side. Girdle equatorial, circular; longitudinal furrow more or less well developed. Wall of the shell two-layered, the outer layer which is covered with small spines, forming the apical horn and antapical projection. A pylome may develop on the dorsal surface of the epitheca.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description:
Lentin and Williams 1976:
Description:
Other genera within the fossil peridinioid group possessing penitabular echinae or processes are Chatangiella, Ginginodinium and Kisselovia. Chatangiella differs from Spinidinium in having an easily discernible endocyst, well developed apical and antapical pericoels, a hepta/pentapartite pericingulum, and an omegaform hexa 2a archeopyle. Ginginodinium has an intercalary archeopyle in which all three intercalaries are removed, or a combination archeopyle in which all three intercalaries are removed, accessory archeopyle sutures tend to be developed between precingulars 2``-3``, 3``-4``, 4``-5`` and 5``-6``. Kisselovia has lateral horns and a quadra intercalary archeopyle resulting from the loss of the second anterior paraplate 2a.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Evitt 1978, p. 124-125:
Synopsis:
Cysts proximochorate, cornucavate or circumcavate, compressed peridinioid to nearly lenticular with an apical horn, an usually well-developed left antapical horn and a reduced right antapical horn; paratabulation peridiniacean, hexa style, indicated on periphragm by intratabular or penitabular ornamentation; smooth pandasuturate areas commonly discernible; archeopyle intercalary, Type I or Ia; archeopyle index <0.5.
Description:
Shape: Compressed peridinioid to nearly lenticular, with an apical horn and a generally well-developed left antapical horn; right antapical horn commonly reduced or absent.
Wall relationships: Cysts generally cornucavate, rarely circumcavate.
Wall features: No parasutural features. Periphragm ornamented with widely to closely spaced cones, spinules, or spines arranged in penitabular rows or intratabular clusters, and commonly separated by smooth, pandasuturate areas; endophragm smooth, usually thin.
Paratabulation: Indicated by penitabular and intratabular features in conjunction with pandasuturate areas; paratabulation peridiniacean, hexa style, formula: ?`, 3a, 7``, Xc, 5```, 2````.
Archeopyle: Intercalary, Type I or Ia (2a only); archeopyle index <0.5; operculum free or attached antapically.
Paracingulum: Indicated in equatorial area by transverse alignment of ornamentation into two parallel rows that commonly delimit a shallow to moderately deep concavity.
Parasulcus: Generally poorly expressed by a shallow depression, mainly on the hypocyst, and by the absence of ornamentation.
Size: Small to intermediate.
Affinities:
Spinidinium differs from Vozzhenikovia in having the ornamentation arranged in penitabular rows or intratabular clusters, or both, rather than being nontabular; and from Ginginodinium in having a Type I rather than a Type 3I intercalary archeopyle.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Spinidinium Cookson and Eisenack, 1962b, emend. Lentin and Williams, 1976. Synopsis from Stover and Evitt (1978, p.124), Cysts proximochorate, cornucavate or circumcavate, compressed peridinioid to nearly lenticular with an apical horn, an unusually well-developed left antapical horn and a reduced right antapical horn; paratabulation peridiniacean, hexa style, indicated on periphragm by intratabular or penitabular ornamentation; smooth pandasuturate areas commonly discernible; archeopyle intercalary, type I or Ia, archeopyle index <0.5. The archeopyle is steno-deltaform.