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Stenodinium
From Williams et al., 2017:
[Stenodinium, Williams et al., 2015, p. 313–314
Type species: as Wetzeliella meckelfeldensis, Gocht, 1969 (pl. 10, fig. 13)]
Stratigraphic occurrence: Early Eocene, Williams et al., 2015
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Original description: [Williams et al., 2015]:
Diagnosis:
Wetzelielloidean cysts with a hyperepeliform archeopyle and processes that are distally free.
Description:
Shape: Dorso-ventral outline of pericyst rhomboidal,with long horns, especially the apical horn; right antapical horn commonly reduced. Dorso-ventral outline of pericyst ovoidal to quadrate.
Wall structure: Periphragm thin, ornamented with nontabular, distally free processes; process tips bifid to aculeate. Endophragm 1-2 µm thick; may be granular.
Pericoels: Cyst cornucavate.
Tabulation: Not apparent other than the archeopyle.
Archeopyle: Hyperepeliform. Perioperculum and endoperculum free.
Furrows: May be faintly indicated by alignment of processes.
Size: Large.
Discussion:
Stenodinium may be distinguished from Rhadinodinium, Sagenodinium and Wilsonidium, other genera with a hyper epeliform archeopyle, on the basis of its distally free, nontabulate processes. Rhadinodiniumhas a pericyst that is smooth or ornamented with features of low relief: Sagenodiniumhas trabeculate processes, and Wilsonidium has penitabular to sutural ornamentation. Other genera with distally free processes are Apectodinium, Axiodinium, Dracodinium and Wetzeliella. Apectodiniumand Axiodinium both have an equiepeliform archeopyle, Dracodinium has a latiepeliform archeopyle and Wetzeliella has a solei-form archeopyle. The holotype of Stenodinium meckelfeldenseis 151 µm long and 140 µm wide, and the endocyst is 84 µm across.
[Stenodinium, Williams et al., 2015, p. 313–314
Type species: as Wetzeliella meckelfeldensis, Gocht, 1969 (pl. 10, fig. 13)]
Stratigraphic occurrence: Early Eocene, Williams et al., 2015
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Williams et al., 2015]:
Diagnosis:
Wetzelielloidean cysts with a hyperepeliform archeopyle and processes that are distally free.
Description:
Shape: Dorso-ventral outline of pericyst rhomboidal,with long horns, especially the apical horn; right antapical horn commonly reduced. Dorso-ventral outline of pericyst ovoidal to quadrate.
Wall structure: Periphragm thin, ornamented with nontabular, distally free processes; process tips bifid to aculeate. Endophragm 1-2 µm thick; may be granular.
Pericoels: Cyst cornucavate.
Tabulation: Not apparent other than the archeopyle.
Archeopyle: Hyperepeliform. Perioperculum and endoperculum free.
Furrows: May be faintly indicated by alignment of processes.
Size: Large.
Discussion:
Stenodinium may be distinguished from Rhadinodinium, Sagenodinium and Wilsonidium, other genera with a hyper epeliform archeopyle, on the basis of its distally free, nontabulate processes. Rhadinodiniumhas a pericyst that is smooth or ornamented with features of low relief: Sagenodiniumhas trabeculate processes, and Wilsonidium has penitabular to sutural ornamentation. Other genera with distally free processes are Apectodinium, Axiodinium, Dracodinium and Wetzeliella. Apectodiniumand Axiodinium both have an equiepeliform archeopyle, Dracodinium has a latiepeliform archeopyle and Wetzeliella has a solei-form archeopyle. The holotype of Stenodinium meckelfeldenseis 151 µm long and 140 µm wide, and the endocyst is 84 µm across.