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Trichodinium speetonense
Trichodinium speetonense Davey, 1974
Originally (and now) Trichodinium, subsequently Occisucysta?. Below, 1981 questionably transferred this species to Occisucysta Gitmez, 1970; however, Lentin and Williams, 1981 retained it in Trichodinium.
Holotype: Davey, 1974, pl.7, figs.2-3; Jan du Chene et al., 1986, pl.121, figs.1-2
Locus typicus: Speeton, England
Stratum typicum: Barremian
Original diagnosis: Davey, 1974, p.63
The cyst is subspherical and has a fibro-pitted wall which bears many elongate conical and thorn-like spines. The spines vary in size, are fibrous and the larger ones often perforate proximally; no definite alignment is noticeable. They appear to be sometimes confined only to intratabular areas and this is particularly noticeable on the dorsal hypotract where the presumed sutural area is devoid of spines. The sulcal depression is similarly devoid of spines The apical horn is a strong, fibrous prolongation of the outer wall and may be spiny; rarely the cyst wall develops an apical budge in the apical region. A large precingular (3") archaeopyle is present, with the operculum sometimes remaining in position.
Dimensions Holotype Range
Central body length 78 µm 69 (81) 97 µm
Central body width 73 µm 60 (74) 89 µm
Apical horn length 11 µm 9 (10) 11 µm
Original description: Davey, 1974, p.63
The spines are pointed distally and arise from a wide base. If two are close together they are usually joined proximally by a membrane or ridge. They vary in length from 2 to 6 µm with the longest occupying the apical, antapical and cingular regions. The sutural area devoid of spines on the dorsal hypotract, extends antapically from the archaeopyle and presumably between postcingular plates 4""" and 5""".
Affinities:
Davey, 1974, p.63: T. speetonensis differs from T. castanea (Deflandre) in that the spines of the latter species are generally truncated or bifurcate distally, are more evenly distributed over the cyst surface and the cyst, itself, is considerably smaller. T. ciliatum (Gocht) possesses a denser covering of evenly spaced spines without a definite distribution and lacks a tabulation.
Originally (and now) Trichodinium, subsequently Occisucysta?. Below, 1981 questionably transferred this species to Occisucysta Gitmez, 1970; however, Lentin and Williams, 1981 retained it in Trichodinium.
Holotype: Davey, 1974, pl.7, figs.2-3; Jan du Chene et al., 1986, pl.121, figs.1-2
Locus typicus: Speeton, England
Stratum typicum: Barremian
Original diagnosis: Davey, 1974, p.63
The cyst is subspherical and has a fibro-pitted wall which bears many elongate conical and thorn-like spines. The spines vary in size, are fibrous and the larger ones often perforate proximally; no definite alignment is noticeable. They appear to be sometimes confined only to intratabular areas and this is particularly noticeable on the dorsal hypotract where the presumed sutural area is devoid of spines. The sulcal depression is similarly devoid of spines The apical horn is a strong, fibrous prolongation of the outer wall and may be spiny; rarely the cyst wall develops an apical budge in the apical region. A large precingular (3") archaeopyle is present, with the operculum sometimes remaining in position.
Dimensions Holotype Range
Central body length 78 µm 69 (81) 97 µm
Central body width 73 µm 60 (74) 89 µm
Apical horn length 11 µm 9 (10) 11 µm
Original description: Davey, 1974, p.63
The spines are pointed distally and arise from a wide base. If two are close together they are usually joined proximally by a membrane or ridge. They vary in length from 2 to 6 µm with the longest occupying the apical, antapical and cingular regions. The sutural area devoid of spines on the dorsal hypotract, extends antapically from the archaeopyle and presumably between postcingular plates 4""" and 5""".
Affinities:
Davey, 1974, p.63: T. speetonensis differs from T. castanea (Deflandre) in that the spines of the latter species are generally truncated or bifurcate distally, are more evenly distributed over the cyst surface and the cyst, itself, is considerably smaller. T. ciliatum (Gocht) possesses a denser covering of evenly spaced spines without a definite distribution and lacks a tabulation.