Back
Moesiodinium
From Williams et al., 2017:
[Moesiodinium, Antonesçu, 1974, p.62; Emendation: Below, 1987a, p. 129
Tax. sr. syn. of Angustidinium Goodman and Evitt, 1981, according to Below, 1987. Lentin and Williams, 1989, retained Angustidinium as a separate genus.
Type species: Moesiodinium raileanui, Antonesçu, 1974 (pl.1, figs.5–8,10–12)]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Antonesçu, 1974]: (Translation: Stover and Evitt 1978, p.113):
Description:
Dinoflagellate with capsule (cavate), rounded to oval in form, more tapered towards the apex. The periphragm shows a tendency to form two small appendices at the antapex. The large round to oval capsule occupies the greater part of the theca and it is enclosed completely and equidistantly by the periphragm. Cingulum helicoidal, dextrogyrate, dividing the theca into two nearly equal halves; the epitheca is slightly larger than the hypotheca. Longitudinal furrow present, barely visible.
Archaeopyle dorsal, intercalary, hexagonal in shape (formed by the loss of the second anterior intercalary plate?). Without other visible traces of tabulation - tabulation probably of the peridinian type. Operculum free, simple.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Expanded diagnosis:
Lentin and Willams, 1976, p. 141-142:
Diagnosis:
Shape: Pericyst: Ambitus rounded to ovoidal. Apex rounded, or with or without "apical pore", which when present forms an indentation. Antapex rounded, or produced into two symmetrically located equal or unequal antapical lobes separated by a concavity. Widest in pericingular region. Epipericyst and hypopericyst of more or less equal size, or epipericyst slightly larger. Dorso-ventrally compressed.
Endocyst: Ambitus rounded to ovoidal, sometimes with a slight antapical indentation. In ambital view detached from the pericyst.
Phragma: Periphragma: Thin, laevigate to possibly granulate. Endophragm: Thin laevigate to granulate.
Paratabulation: Pericyst: Paratabulation indeterminate other than in the vicinity of the archaeopyle.
Pericingulum: Clearly delineated by folds or broad ridges. Dextrorotatory. Forms an indentation on the ambitus of the pericyst.
Perisulcus: When visible only faintly delineated. Present on both epipericyst and hypopericyst. Extending to antapex. Widening posteriorly.
Endocyst: Paratabulation indeterminate other than in the vicinity of the archaeopyle.
Archaeopyle: Periarchaeopyle: Hexagonal, intercalary resulting from the loss of a single intercalary paraplate. The shape of the posterior parasuture indicates that the intercalary paraplate lost in archaeopyle formation was located between two precingular paraplates and not directly above 4`` as in the Type I archaeopyle characteristic of the post-Jurassic. Perioperculum free. Endoarchaeopyle: Appears to be hexagonal intercalary and of identical shape to the periarchaeopyle. Archaeopyle formula: I/I?
Dimensions:
Pericyst: Length 30-35 µm, breadth 32 µm.
Endocyst diameter: 25 µm.
Affinities:
Moesiodinium is characterized by the rounded to ovoidal pericyst with antapical lobes, the ambital pericoel and the very distinctive hexagonal archaeopyle which lacks the straight posterior parasuture of most other peridinoid dinoflagellate cysts, rather having a margin that indicates abutment against two rather than one precingular. This is analogous to the archaeopyle in Broomea ramosa Cookson and Eisenack. The characteristic outline of the archaeopyle readily separates it from other genera with an I archaeopyle, apart from Broomea.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Evitt, 1978, p. 113:
Synopsis:
Cysts proximate, circumcavate, lenticular, with poorly developed antapical lobes; pericoel entire; distance between endocyst and pericyst about equal in dorsal-ventral view; paratabulation indicated by dextrorotatory paracingulum and archaeopyle; latter intercalary, Type I.
Description:
Shape: Lenticular with obtusely angular apex and poorly developed antapical lobes separated by a shallow, medial concavity.
Wall relationships: Cysts circumcavate; endocyst and pericyst relatively widely and uniformly separated.
Wall features: No parasutural features. Endophragm smooth to irregularly granulate; periphragm smooth.
Paratabulation: Indicated by archaeopyle and paracingulum.
Archaeopyle: Intercalary, Type I(2a only); antapical segment of archaeopyle margin broadly V-shaped; operculum free.
Paracingulum: Indicated by low, parallel, transverse, equatorial folds or low ridges; dextrorotatory.
Parasulcus: Barely discernible.
Size: Small.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description:
Below, 1987: (Translation: Secretary of State, Canada, Translation Bureau, p. 325):
Diagnosis:
Arrangement of vesicles/plates on the dinoflagellate amphiesma cop, pop, cap, 5`, 3a, 7-6``, 7c, 5```, 2````, as, z, y, ps; 1```` and 2```` located symmetrically on either side of the dorso-ventral plane; growth type of thecal plates peridinoidal.
Cyst habit proximate, proximochorate, chorate, peridinoidal, lenticular, poles rounded or with apical horn and one or two antapical protruberances, acavate, cavate; wall composed of pedium and luxuria, luxuria usually forming a tectum; surface of the endoblast then smooth, ornamented, periblast smooth, ornamented, areate, nonareate; areation marked by finate or intraareate ornaments or limbi, areation formula NR PR/cop, pop, cap, NR`/5`, NRa/3a, NR``/7``-6``, NRc/7c, NR```/5```, NR````/2````, NRs/as, y, z, ps; archaeopyle anterior intercalary, 2a; operculum monoareate, secate, opercular formula 2a(s).
Affinities:
Moesiodinium differs from Subtilisphaera in having an intercalary archaeopyle. A unique feature about Moesiodinium is its dextrorotatory paracingulum.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Moesiodinium Antonesçu, 1974, emend. Below, 1987a. According to Feist-Burkhardt (1994), this cavate genus has a type I archeopyle with a free (secate) operculum. Below (1987a) emended the genus as follows: Arrangement of plates on the amphiesma cop, pop, cap, 5`, 3a, 7"-6", 7c, 5"', 2"'', as, z, y, ps, . 1"'' and 2"'' located symmetrically on either side of the dorsoventral plane, growth type of thecal plates peridinioid. Cystic habit proximate, proximochorate, chorate, peridinioidal, lenticular, poles rounded or with apical horn and one or two antapical protuberances, acavate, cavate; wall composed of pedium and luxuria, luxuria usually forming a tectum; surface of the endoblast smooth or ornamented, surface of the periblast smooth, ornamented, areate, nonareate; areation marked by finite or intraareate ornaments or limbi. Archeopyle anterior intercalary, 2a operculum monoareate, secated.
[Moesiodinium, Antonesçu, 1974, p.62; Emendation: Below, 1987a, p. 129
Tax. sr. syn. of Angustidinium Goodman and Evitt, 1981, according to Below, 1987. Lentin and Williams, 1989, retained Angustidinium as a separate genus.
Type species: Moesiodinium raileanui, Antonesçu, 1974 (pl.1, figs.5–8,10–12)]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Antonesçu, 1974]: (Translation: Stover and Evitt 1978, p.113):
Description:
Dinoflagellate with capsule (cavate), rounded to oval in form, more tapered towards the apex. The periphragm shows a tendency to form two small appendices at the antapex. The large round to oval capsule occupies the greater part of the theca and it is enclosed completely and equidistantly by the periphragm. Cingulum helicoidal, dextrogyrate, dividing the theca into two nearly equal halves; the epitheca is slightly larger than the hypotheca. Longitudinal furrow present, barely visible.
Archaeopyle dorsal, intercalary, hexagonal in shape (formed by the loss of the second anterior intercalary plate?). Without other visible traces of tabulation - tabulation probably of the peridinian type. Operculum free, simple.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Expanded diagnosis:
Lentin and Willams, 1976, p. 141-142:
Diagnosis:
Shape: Pericyst: Ambitus rounded to ovoidal. Apex rounded, or with or without "apical pore", which when present forms an indentation. Antapex rounded, or produced into two symmetrically located equal or unequal antapical lobes separated by a concavity. Widest in pericingular region. Epipericyst and hypopericyst of more or less equal size, or epipericyst slightly larger. Dorso-ventrally compressed.
Endocyst: Ambitus rounded to ovoidal, sometimes with a slight antapical indentation. In ambital view detached from the pericyst.
Phragma: Periphragma: Thin, laevigate to possibly granulate. Endophragm: Thin laevigate to granulate.
Paratabulation: Pericyst: Paratabulation indeterminate other than in the vicinity of the archaeopyle.
Pericingulum: Clearly delineated by folds or broad ridges. Dextrorotatory. Forms an indentation on the ambitus of the pericyst.
Perisulcus: When visible only faintly delineated. Present on both epipericyst and hypopericyst. Extending to antapex. Widening posteriorly.
Endocyst: Paratabulation indeterminate other than in the vicinity of the archaeopyle.
Archaeopyle: Periarchaeopyle: Hexagonal, intercalary resulting from the loss of a single intercalary paraplate. The shape of the posterior parasuture indicates that the intercalary paraplate lost in archaeopyle formation was located between two precingular paraplates and not directly above 4`` as in the Type I archaeopyle characteristic of the post-Jurassic. Perioperculum free. Endoarchaeopyle: Appears to be hexagonal intercalary and of identical shape to the periarchaeopyle. Archaeopyle formula: I/I?
Dimensions:
Pericyst: Length 30-35 µm, breadth 32 µm.
Endocyst diameter: 25 µm.
Affinities:
Moesiodinium is characterized by the rounded to ovoidal pericyst with antapical lobes, the ambital pericoel and the very distinctive hexagonal archaeopyle which lacks the straight posterior parasuture of most other peridinoid dinoflagellate cysts, rather having a margin that indicates abutment against two rather than one precingular. This is analogous to the archaeopyle in Broomea ramosa Cookson and Eisenack. The characteristic outline of the archaeopyle readily separates it from other genera with an I archaeopyle, apart from Broomea.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Evitt, 1978, p. 113:
Synopsis:
Cysts proximate, circumcavate, lenticular, with poorly developed antapical lobes; pericoel entire; distance between endocyst and pericyst about equal in dorsal-ventral view; paratabulation indicated by dextrorotatory paracingulum and archaeopyle; latter intercalary, Type I.
Description:
Shape: Lenticular with obtusely angular apex and poorly developed antapical lobes separated by a shallow, medial concavity.
Wall relationships: Cysts circumcavate; endocyst and pericyst relatively widely and uniformly separated.
Wall features: No parasutural features. Endophragm smooth to irregularly granulate; periphragm smooth.
Paratabulation: Indicated by archaeopyle and paracingulum.
Archaeopyle: Intercalary, Type I(2a only); antapical segment of archaeopyle margin broadly V-shaped; operculum free.
Paracingulum: Indicated by low, parallel, transverse, equatorial folds or low ridges; dextrorotatory.
Parasulcus: Barely discernible.
Size: Small.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description:
Below, 1987: (Translation: Secretary of State, Canada, Translation Bureau, p. 325):
Diagnosis:
Arrangement of vesicles/plates on the dinoflagellate amphiesma cop, pop, cap, 5`, 3a, 7-6``, 7c, 5```, 2````, as, z, y, ps; 1```` and 2```` located symmetrically on either side of the dorso-ventral plane; growth type of thecal plates peridinoidal.
Cyst habit proximate, proximochorate, chorate, peridinoidal, lenticular, poles rounded or with apical horn and one or two antapical protruberances, acavate, cavate; wall composed of pedium and luxuria, luxuria usually forming a tectum; surface of the endoblast then smooth, ornamented, periblast smooth, ornamented, areate, nonareate; areation marked by finate or intraareate ornaments or limbi, areation formula NR PR/cop, pop, cap, NR`/5`, NRa/3a, NR``/7``-6``, NRc/7c, NR```/5```, NR````/2````, NRs/as, y, z, ps; archaeopyle anterior intercalary, 2a; operculum monoareate, secate, opercular formula 2a(s).
Affinities:
Moesiodinium differs from Subtilisphaera in having an intercalary archaeopyle. A unique feature about Moesiodinium is its dextrorotatory paracingulum.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Moesiodinium Antonesçu, 1974, emend. Below, 1987a. According to Feist-Burkhardt (1994), this cavate genus has a type I archeopyle with a free (secate) operculum. Below (1987a) emended the genus as follows: Arrangement of plates on the amphiesma cop, pop, cap, 5`, 3a, 7"-6", 7c, 5"', 2"'', as, z, y, ps, . 1"'' and 2"'' located symmetrically on either side of the dorsoventral plane, growth type of thecal plates peridinioid. Cystic habit proximate, proximochorate, chorate, peridinioidal, lenticular, poles rounded or with apical horn and one or two antapical protuberances, acavate, cavate; wall composed of pedium and luxuria, luxuria usually forming a tectum; surface of the endoblast smooth or ornamented, surface of the periblast smooth, ornamented, areate, nonareate; areation marked by finite or intraareate ornaments or limbi. Archeopyle anterior intercalary, 2a operculum monoareate, secated.