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Wallodinium lagunum
From Fensome et al., 2019:
Wallodinium laganum Feist-Burkhardt and Monteil 1994
Holotype Feist-Burkhardt and Monteil 1994: pl. 4, fig. 2
Locus typicus: Burton Bradstock, Dorset, England
Stratum typicum: Late Toarcian, Levesquei Zone, Aalensis Subzone
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Description: Feist-Burkhardt and Monteil 1994, p. 7-8
Dinoflagellate cyst. Proximate, epicavate, with straight longitudinal axis. Pericyst stocky, subcylindrical with a broadly rounded antapex. Endocyst subspherical to ellipsoidal, occupying most of the hypocyst, closely appressed to the pericyst in the hypocystal region. Peri- and endophragm psilate to scabrate. Peri- and endo-archaeopyle apical, type (tA)a. Peri- and endoperculum ventrally adnate. attached by a narrow stalk-like sulcal tongue; both opercula flat, dish-shaped. Paratabulation generally expressed by archaeopyle only. Paracingulum may be indicated by a weak constriction situated at about half the cyst length, where the periphragm becomes detached from endophragm, sometimes also indicated on endocyst by a more accentuated ornamentation, scabrate to finely granulate. Parasulcus not indicated, except as. Flagellar pore imprint sometimes present.
Observed size range: Length of pericyst: 35-44 µm; width of pericyst: 21-29 µm; length of endocyst: 26-31 µm; width of endocyst: 21-29 µm; diameter perioperculum: 13-16 µm; diameter of endoperculum:
12-15 µm.
Remarks: Feist-Burkhardt and Monteil 1994, p. 7-8
Prauss (1989) was the first who illustrated specimens of this species showing the typical flat dish-shaped adnate endo- and perioperculum. Although the varying coarseness of the endocyst ornamentation on the paracingulum, described by Prauss (1989, p.47), is not observed in our material from England, it has been included in the diagnosis. Prauss"s specimens also differ in being considerably larger (pericyst from 38 µm to 71 µm long and 27 µm to 56 µm wide).
Comparisons (Tabl. 1): Wallodinium laganum n..sp. differs from Wallodinium cylindr-iculn n. emend. in having an adnate, typical dish-shaped, rather than free, dome-shaped apical perioperculum. It differs also in having an endocyst which occupies most of the hypocyst, closely appressed to the pericyst in the hypocystal region, rather than a relatively free and sometimes lacking endocyst. Furthermore, in Wallodinium laganum n. sp. the paracingular zone is sometimes indicated by an accentuated ornamentation on the endocyst, whereas both wall-layers of Wallodinium cylindricum are psilate.
Previously reported occurrences: Because of the confusion with other species in the literature, only the recorded occurrences of figured specimens are considered in the following account. Wallodinium laganum n. sp. is undoubtedly known only from the Late Toarcian Levesquei Zone of England (Riding, 1984), Scotland (Riding et al. 1991) and N-Germany (Prauss, 1989), and the Toarcian of Spitsbergen (Bjaerke, 1980). In the present study, specimens of Wallodinium laganum n. sp. have been found in the Late Toarcian Levesquei Zone and the Early Aalenian Scissum Zone of Burton Bradstock, England.
synonyms: ( Feist-Burkhardt and Monteil 1994, p. 7-8)
1980 - Fromea sp. - Bjaerke, pl. 2, fig. 13.
?1983 - Wallodinium elongatum (Beju 1971) Duxbury
1980 - Davies, pl. 2, fig. 9.
1984 - Wallodinium cylindricum (Habib 1970) Duxbury
1983 - Riding, p. 120, fig. 6 E,F.
1989 - Wallodinium cylindricum (Habib 1970) Duxbury
1983 emend. - Prauss, p.47, 48, pl. 2, fig. 6-11, Fig. 23.
pars 1991 - Wallodinium elongatum (Beju 1971) Duxbury 1980 - Riding et al., pl. 3, fig. 13-17, non pl. 4, fig. 15-17.
pars 1992 - Wallodinium cylindricum (HABIB 1970) Duxbury 1983 - Riding & Thomas, pl. 2.2, fig. 6, 7, non pl. 2.4, fig. 9, 10.
Wallodinium laganum Feist-Burkhardt and Monteil 1994
Holotype Feist-Burkhardt and Monteil 1994: pl. 4, fig. 2
Locus typicus: Burton Bradstock, Dorset, England
Stratum typicum: Late Toarcian, Levesquei Zone, Aalensis Subzone
---------------------------------------------------------------------------------------------------
Description: Feist-Burkhardt and Monteil 1994, p. 7-8
Dinoflagellate cyst. Proximate, epicavate, with straight longitudinal axis. Pericyst stocky, subcylindrical with a broadly rounded antapex. Endocyst subspherical to ellipsoidal, occupying most of the hypocyst, closely appressed to the pericyst in the hypocystal region. Peri- and endophragm psilate to scabrate. Peri- and endo-archaeopyle apical, type (tA)a. Peri- and endoperculum ventrally adnate. attached by a narrow stalk-like sulcal tongue; both opercula flat, dish-shaped. Paratabulation generally expressed by archaeopyle only. Paracingulum may be indicated by a weak constriction situated at about half the cyst length, where the periphragm becomes detached from endophragm, sometimes also indicated on endocyst by a more accentuated ornamentation, scabrate to finely granulate. Parasulcus not indicated, except as. Flagellar pore imprint sometimes present.
Observed size range: Length of pericyst: 35-44 µm; width of pericyst: 21-29 µm; length of endocyst: 26-31 µm; width of endocyst: 21-29 µm; diameter perioperculum: 13-16 µm; diameter of endoperculum:
12-15 µm.
Remarks: Feist-Burkhardt and Monteil 1994, p. 7-8
Prauss (1989) was the first who illustrated specimens of this species showing the typical flat dish-shaped adnate endo- and perioperculum. Although the varying coarseness of the endocyst ornamentation on the paracingulum, described by Prauss (1989, p.47), is not observed in our material from England, it has been included in the diagnosis. Prauss"s specimens also differ in being considerably larger (pericyst from 38 µm to 71 µm long and 27 µm to 56 µm wide).
Comparisons (Tabl. 1): Wallodinium laganum n..sp. differs from Wallodinium cylindr-iculn n. emend. in having an adnate, typical dish-shaped, rather than free, dome-shaped apical perioperculum. It differs also in having an endocyst which occupies most of the hypocyst, closely appressed to the pericyst in the hypocystal region, rather than a relatively free and sometimes lacking endocyst. Furthermore, in Wallodinium laganum n. sp. the paracingular zone is sometimes indicated by an accentuated ornamentation on the endocyst, whereas both wall-layers of Wallodinium cylindricum are psilate.
Previously reported occurrences: Because of the confusion with other species in the literature, only the recorded occurrences of figured specimens are considered in the following account. Wallodinium laganum n. sp. is undoubtedly known only from the Late Toarcian Levesquei Zone of England (Riding, 1984), Scotland (Riding et al. 1991) and N-Germany (Prauss, 1989), and the Toarcian of Spitsbergen (Bjaerke, 1980). In the present study, specimens of Wallodinium laganum n. sp. have been found in the Late Toarcian Levesquei Zone and the Early Aalenian Scissum Zone of Burton Bradstock, England.
synonyms: ( Feist-Burkhardt and Monteil 1994, p. 7-8)
1980 - Fromea sp. - Bjaerke, pl. 2, fig. 13.
?1983 - Wallodinium elongatum (Beju 1971) Duxbury
1980 - Davies, pl. 2, fig. 9.
1984 - Wallodinium cylindricum (Habib 1970) Duxbury
1983 - Riding, p. 120, fig. 6 E,F.
1989 - Wallodinium cylindricum (Habib 1970) Duxbury
1983 emend. - Prauss, p.47, 48, pl. 2, fig. 6-11, Fig. 23.
pars 1991 - Wallodinium elongatum (Beju 1971) Duxbury 1980 - Riding et al., pl. 3, fig. 13-17, non pl. 4, fig. 15-17.
pars 1992 - Wallodinium cylindricum (HABIB 1970) Duxbury 1983 - Riding & Thomas, pl. 2.2, fig. 6, 7, non pl. 2.4, fig. 9, 10.