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Valvaeodinium
From Fensome et al., 2019:
Morgenroth, 1970, p.350. Emendation: Below, 1987b, p.64–65.
Taxonomic junior synonyms: Kylindrocysta, Comparodinium and Opaeopsomus, all according to Below (1987b, p.64) -- however, Lentin and Williams (1993, p.465) retained Opaeopsomus.
Type: Morgenroth, 1970, pl.11, figs.1–2, as Valvaeodinium armatum.
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Original description: [Morgenroth, 1970]: (Translation: Stover and Evitt, 1978, p. 129 (description) and LPP (affinities)):
Description:
Dinoflagellate cysts reflecting the following tabulation: 4`, 2a, 5``, ?5c or 6c, 5```, 0p, 1````. Sulcus present; cingulum laevo-rotatory. Test without apical or antapical horns. Archeopyle intercalary. The operculum consists of the 2 anterior intercalary plates (Archeopyle type: 2I).
Affinities:
This genus can be distinguished from Pareodinia Deflandre 1947 which seems also to have an intercalary archeopyle composed of two plates (Evitt, 1967) by the presence of a clearly reflected tabulation and the absence of an apical horn.
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Modified description:
Stover and Evitt 1978, p. 129:
Synopsis: Cysts proximate, subspherical; paratabulation indicated by low parasutural ridges; paraplates spinose; archeopyle intercalary, Type 2I.
Description:
Shape: Subsphherical.
Wall relationships: Autophragm only.
Wall features: Low parasutural ridges delimit paraplates. Periphragm punctoreticulate between the bases of nontabular short spines. Paratabulation: Indicated by parasutural features; formula: 4`, 2a, 5``, Xc, 5```, 1````.
Archeopyle: Intercalary, type 2I (1a, 2a); operculum free.
Paracingulum: Vaguely indicated by shallow transverse equatorial concavity, expressed most clearly at the lateral margins.
Parasulcus: Apparently expressed as a poorly delimited depression, which is widest at the paracingulum and becomes narrower apically and antapically.
Size: Small.
Affinities:
Valvaeodinium differs from Pluriarvalium in having spinose paraplates and a Type 2I intercalary archeopyle, and in lacking an apical horn as well as posterior intercalary paraplates. Pluriarvalium has either a Type I or 3I intercalary archeopyle. Pareodinia has a Type 2I or 3I intercalary archeopyle; it differs from Valvaeodinium in having an apical horn and in lacking parasutural features.
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Emended description:
Below, 1987b: (Translation: Bureau of Translation, Secretary of State Canada, 1988, Part II, p. 179-184):
Diagnosis:
Arrangement of vesicles/plates of the dinoflagellate amphiesma PR, 4`, 1a, 5`` (-6``), 6c, 5```, 1````, ns; growth of plates peridinoidal.
Cyst habit proximate, chorate, skolochorate, acavate, cavate, polyhedral, sphaeroidal, ovaloidal, ellipsoidal, cylindroidal with rounded poles, often elongate; size medium to small; wall composed of pedium and luxuria, surface glabrous, ornamented or with processes, nonareate or areate, areation marked by finate ornament, limbi, or intraareate ornament; areation formula NR PR/PR, NR`/4/, NRa/1a, NR``/5``/6``, NRc/6c, NR```/5```, NR````/1````, NRs/ns; archaeopyle apical/anterior intercalary, 3`+1a, seldom PR+1`+2`+3`+4`+1a; operculum solvate, secate, general opercular formula usually 3`(s)=1a(s), seldom PR(s)+1`(s)+2`(s)+3`(s)+4`(s)+1a(s).
Affinities:
(annotated) The areation and archaeopyle type of Valvaeodinium are found in numerous Rhaetian, Liassic and Dogger dinocysts. Some of these specimens show the areation directly through the finate, limbate or intraareate arrangement of the ornaments. Other taxa which are glabrous or densely ornamented can be assigned to this genus on the basis of the shape of the cyst, but especially because of the unmistakably characteristic octagonal shape of the archaeopyle, and the position of the exit hole.
Comparodinium and Kylindrocysta are junior synonyms of Valvaeodinium.
The heterogeneous genus Valvaeodinium comprises taxa with a spheroidal to elongate habit, proximate as well as skolochorate cysts, two rather different types of archaeopyle, and even cavate species.
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Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Valvaeodinium Morgenroth, 1970, emend. Below, 1987b. Revised diagnosis by Below (1987b, p 64). Plate formula is pr., 4`, 1a, 5" (6"), 6c, 5"' , 1"'' , ns. The growth of the plates is peridinioid. The cyst is proximate, chorate, skolochorate, acavate, cavate, polyhedral, spheroidal, ovaloidal, ellipsoidal, cylindroidal with rounder poles, often elongate. Size medium to small: wall composed of pedium and luxuria, surface glabrous, ornamented or with processes, parasutural or nontabular, tabulation marked by finite ornamentation, limbi or intraareate ornament: Archeopyle apical/anterior intercalary 3` + 1a, seldom pr + 1` + 2` + 3` + 4` + 1a: operculum solvate, secate, general opercular formula usually 3`s + 1as. Feist-Burkhardt and Monteil (1997, p.48) noted that several species of Valvaeodinium have more elongate central bodies in younger strata, with specimens from older strata being spherical or subspherical.
Morgenroth, 1970, p.350. Emendation: Below, 1987b, p.64–65.
Taxonomic junior synonyms: Kylindrocysta, Comparodinium and Opaeopsomus, all according to Below (1987b, p.64) -- however, Lentin and Williams (1993, p.465) retained Opaeopsomus.
Type: Morgenroth, 1970, pl.11, figs.1–2, as Valvaeodinium armatum.
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Original description: [Morgenroth, 1970]: (Translation: Stover and Evitt, 1978, p. 129 (description) and LPP (affinities)):
Description:
Dinoflagellate cysts reflecting the following tabulation: 4`, 2a, 5``, ?5c or 6c, 5```, 0p, 1````. Sulcus present; cingulum laevo-rotatory. Test without apical or antapical horns. Archeopyle intercalary. The operculum consists of the 2 anterior intercalary plates (Archeopyle type: 2I).
Affinities:
This genus can be distinguished from Pareodinia Deflandre 1947 which seems also to have an intercalary archeopyle composed of two plates (Evitt, 1967) by the presence of a clearly reflected tabulation and the absence of an apical horn.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Evitt 1978, p. 129:
Synopsis: Cysts proximate, subspherical; paratabulation indicated by low parasutural ridges; paraplates spinose; archeopyle intercalary, Type 2I.
Description:
Shape: Subsphherical.
Wall relationships: Autophragm only.
Wall features: Low parasutural ridges delimit paraplates. Periphragm punctoreticulate between the bases of nontabular short spines. Paratabulation: Indicated by parasutural features; formula: 4`, 2a, 5``, Xc, 5```, 1````.
Archeopyle: Intercalary, type 2I (1a, 2a); operculum free.
Paracingulum: Vaguely indicated by shallow transverse equatorial concavity, expressed most clearly at the lateral margins.
Parasulcus: Apparently expressed as a poorly delimited depression, which is widest at the paracingulum and becomes narrower apically and antapically.
Size: Small.
Affinities:
Valvaeodinium differs from Pluriarvalium in having spinose paraplates and a Type 2I intercalary archeopyle, and in lacking an apical horn as well as posterior intercalary paraplates. Pluriarvalium has either a Type I or 3I intercalary archeopyle. Pareodinia has a Type 2I or 3I intercalary archeopyle; it differs from Valvaeodinium in having an apical horn and in lacking parasutural features.
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Emended description:
Below, 1987b: (Translation: Bureau of Translation, Secretary of State Canada, 1988, Part II, p. 179-184):
Diagnosis:
Arrangement of vesicles/plates of the dinoflagellate amphiesma PR, 4`, 1a, 5`` (-6``), 6c, 5```, 1````, ns; growth of plates peridinoidal.
Cyst habit proximate, chorate, skolochorate, acavate, cavate, polyhedral, sphaeroidal, ovaloidal, ellipsoidal, cylindroidal with rounded poles, often elongate; size medium to small; wall composed of pedium and luxuria, surface glabrous, ornamented or with processes, nonareate or areate, areation marked by finate ornament, limbi, or intraareate ornament; areation formula NR PR/PR, NR`/4/, NRa/1a, NR``/5``/6``, NRc/6c, NR```/5```, NR````/1````, NRs/ns; archaeopyle apical/anterior intercalary, 3`+1a, seldom PR+1`+2`+3`+4`+1a; operculum solvate, secate, general opercular formula usually 3`(s)=1a(s), seldom PR(s)+1`(s)+2`(s)+3`(s)+4`(s)+1a(s).
Affinities:
(annotated) The areation and archaeopyle type of Valvaeodinium are found in numerous Rhaetian, Liassic and Dogger dinocysts. Some of these specimens show the areation directly through the finate, limbate or intraareate arrangement of the ornaments. Other taxa which are glabrous or densely ornamented can be assigned to this genus on the basis of the shape of the cyst, but especially because of the unmistakably characteristic octagonal shape of the archaeopyle, and the position of the exit hole.
Comparodinium and Kylindrocysta are junior synonyms of Valvaeodinium.
The heterogeneous genus Valvaeodinium comprises taxa with a spheroidal to elongate habit, proximate as well as skolochorate cysts, two rather different types of archaeopyle, and even cavate species.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Valvaeodinium Morgenroth, 1970, emend. Below, 1987b. Revised diagnosis by Below (1987b, p 64). Plate formula is pr., 4`, 1a, 5" (6"), 6c, 5"' , 1"'' , ns. The growth of the plates is peridinioid. The cyst is proximate, chorate, skolochorate, acavate, cavate, polyhedral, spheroidal, ovaloidal, ellipsoidal, cylindroidal with rounder poles, often elongate. Size medium to small: wall composed of pedium and luxuria, surface glabrous, ornamented or with processes, parasutural or nontabular, tabulation marked by finite ornamentation, limbi or intraareate ornament: Archeopyle apical/anterior intercalary 3` + 1a, seldom pr + 1` + 2` + 3` + 4` + 1a: operculum solvate, secate, general opercular formula usually 3`s + 1as. Feist-Burkhardt and Monteil (1997, p.48) noted that several species of Valvaeodinium have more elongate central bodies in younger strata, with specimens from older strata being spherical or subspherical.