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Dodekovia
From Fensome et al., 2019:
Dodekovia, Dörhöfer and Davies, 1980, p.26.
Emendation: Below, 1987a, p.113–114.
Taxonomic senior synonym: Apteodinium, according to Stover and Williams (1987, p.87) -- however, Prauss (1989, p.18) and Fensome et al. (1993b, p.149–150) retained Dodekovia.
Taxonomic junior synonyms: Ovalicysta, Parvocysta and Susadinium, all according to Below (1987a, p.113) -- however, Stover and Williams (1987, p.169,171,209) and Lentin and Williams (1989, p.269,284,358) retained Ovalicysta, Parvocysta and Susadinium.
Type: Dörhöfer and Davies, 1980, figs.26A–D, as Dodekovia syzygia.
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Original description: [Dörhöfer and Davies, 1980]:
Diagnosis:
Proximate dinoflagellate cyst with elongate ovoidal to spherical shape. Apex slightly pointed, occasionally with a short horn. Cyst wall two- layered, fibrous between endo- and periphragm. Surface of periphragm smooth, granulate, or finely reticulate.
Tabulation faintly expressed. Tabulation formula: 4`, 5a, 9``, 8c, 9```, 2p, 2````, 4s;
archaeopyle 3P3I.
Affinities:
Dodekovia differs from Tectatodinium Wall 1967 in archaeopyle formation (P3 in Tectatodinium). Dodekovia resembles Cribroperidinium; however, the latter has a different paratabulation (no anterior intercalary plates, Eaton 1976), is much larger, and has a long apical horn. A common feature in Dodekovia is the presence of sutural traces on the operculum. Apteodinium normally lacks tabulation and has a P3 archaeopyle. Gocht (1970: pl.34, figs.25-29) figured several specimens from the Bathonian of Germany as indeterminate genera, which most probably represent specimens of Dodekovia. The removal of one or two opercular pieces, each representing fused intercalary with precingular plates, are vestiges of the desintegration archaeopyle.
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Emended description:
Below, 1987: (Translation: Fensome et al., 1991, p. 182):
Diagnosis:
Arrangement of vesicles/plates on the dinoflagellate amphiessma 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 peridinoidal.
Cystic habit proximate, proximochorate, chorate, spheroidal, guttiform, ovoidal, ovaloidal, ellipsoidal, rarely peridinoidal, poles rounded or with apical horn and 1-2 antapical protruberances, equatorial cross section usually circular or oval, acavate, cavate; size variable; wall composed of pedium only, or pedium with usually rigid, prismatic-fibrose luxuria, luxuria forming tegillum and tectum; surface glabrous, ornamented, areate, nonareate; areation marked by finate or intraareate ornaments, limbi or intraareate protruberances; areation formula NR PR/cop, pop, cap, NR`/5`, NRa/3a, NR``/7``-6``, NRc/Xc/7c, NR```/5```, NR````/2````, NRs/Xs/as, x, y, z, ps; archaeopyle anterior intercalary, 2a; operculum monoareate, secate, opercular formula 2a(s).
Affinities:
Dörhöfer and Davies` (1980) diagnosis of the monotypic genus Dodekovia stipulates an areation of 4`, 5a, 9``, 8c, 9```, 2p, 2````, 4s and a type 3P3I archaeopyle. This areation formula and the arrangement of areae and archaeopyle presented by Dörhöfer and Davies (1980, fig.10) definitely are not supported by SEM investigations of the type species Dodekovia syzygia. Instead, areate specimens of this species show the typical pattern cop, pop, cap, 5`, 3a, 7``-6``, 7c, 5```, 2````, ns. The archaeopyle is monoareate and anterior intercalary, 2a(s).
Ovalicysta hiata Bjærke 1980, the type species of the genus Ovalicysta, is synonymous with Dodekovia syzygia, so that this genus must be absorbed. However, the same applies to the genera Susadinium Dörhöfer and Davies 1980 and parvocyst Bjærke 1980. Morphologically the typespecies of these three genera are very different. Dodekovia syzygia has a guttiform habit, Parvocysta bullula a peridinoidal habit, and Susadinium scrofoides strikingly protruberant areae. There are also differences in the wall structure. Dodekovia syzygia has a thick wall composed of pedium and spongy-prismatic luxuria, whereas both Parvocysta bullula and Susadinium scrofoides form only a thin, glabrous or scabrate peddium. However, material from the Toarcian and Aalenian contains numerous morphological transitional forms which mediate between the extremes and prove their taxonomic affinity. The series of variants will be fully outlined here.
1. Dodekovia syzygia, wall composed of pedium and spongy prismatic luxuria, surface smooth, habit guttiform, small apical horn.
1a: variation of Dodekovia: formation of a tegillum through distal fusion of the luxuriate fibrils leads to a variant with a continuous inner and outer "envelope" (pedium and tegilum, connected by fibrils; Evitt`s "differentiated autophragm".
1b: reduction of the filling between pedium and tegillum transforms the tegillum into a free tectum above the pedium, still connected with the pedium only locally. The cyst is then cavate between the endoblast and the periblast; if its habit is also changed in the process from guttiform to typically peridinoidal with a reniform, lenticular equatorial cross section, this leads over into taxa of the genus Moesiodinium.
2. Dodekovia syzygia.
2a: modification of the habit to oval or spheroidal taxa without apical protruberances, nonareate, but with the wall still composed of pedium and prismatic luxuria; Dodekovia pseudochytroides, Dodekovia reiculata.
3. Dodekovia syzygia.
3a: areae demarcated by means of luxuria of different thickness, and thus by areae protruberances of different prominence (Dodekovia pinna).
4. Dodekovia pinna.
4a: reduction of limbate luxuria so that intraareate luxuria becomes distinctly protruberant like an elevation, separated by finate septa (Dodekovia tabulata).
4b: complete reduction of areate luxuria, cyst consisting of pedium and finate luxuriate septa, variant of Dodekovia tabulata.
4c: extensive reduction of areae, pedium with traces of finate luxuria (variant of Dodekovia tabulata).
5. Whereas in Dodeekovia pinna and Dodekovia tabulata area protruberances are formed only by ornaments off the luxuria, in the next group the entire cyst wall with the exception of the cingulum forms sometimes very striking angular protrusions tracing the area outlines (Dodekovia knertensis).
5a: luxuriate ornaments only on rounded intraareate pedium prorubrenaces (Dodekovia scrofoides var. penicillus).
5b: complete reduction of luxuria, slight dorsoventral flattening (Dodekovia scrofoides var. scrofoides).
5c: Severe dorsoventral flattening into a peridinoidal habit, and drastic reduction of area protruberances leads over to the structure of Dodekovia bullula. However, perhaps this structure can also be derived through reduction of the tectum from the peridinoidal structure of Moesiodinium?
Reutlingia has a monoareate, adnate operculum 2a. Moesiodinium is cavate and has a peridinoidal habit, and Pyxidiella Cookson and Eisenack, 1958 is elongate, cylindroform.
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Stover and Williams, 1987, p. 87:
Remarks:
Examination of specimens of the type species of Dodekovia, D. syzygia, filed to reveal evidence for the elaborate and complex paratabulation scheme presented in Dörhöfer and Davies, 1980 (fig.11). The holotype (and best preserved specimen of the types) appears to be a relatively uncomplicated, subspherical cyst with a short apical protrusion and a simple, middorsal, precingular (3``) archaeopyle. Indications of paratabulation, other than the archaeopyle, are lacking. It is on the basis of these observations that the new combination, Apteodinium syzygium, is made.
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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.
Dodekovia Dörhöfer and Davies, 1980, emend. Below, 1987a. From Feist-Burkhardt (1995), This genus has a type I archeopyle with a free operculum. Feist-Burkhardt follows Below (1987) in considering it to be the taxonomic senior synonym of Ovalicysta, Parvocysta and Susadinium .
Dodekovia, Dörhöfer and Davies, 1980, p.26.
Emendation: Below, 1987a, p.113–114.
Taxonomic senior synonym: Apteodinium, according to Stover and Williams (1987, p.87) -- however, Prauss (1989, p.18) and Fensome et al. (1993b, p.149–150) retained Dodekovia.
Taxonomic junior synonyms: Ovalicysta, Parvocysta and Susadinium, all according to Below (1987a, p.113) -- however, Stover and Williams (1987, p.169,171,209) and Lentin and Williams (1989, p.269,284,358) retained Ovalicysta, Parvocysta and Susadinium.
Type: Dörhöfer and Davies, 1980, figs.26A–D, as Dodekovia syzygia.
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Original description: [Dörhöfer and Davies, 1980]:
Diagnosis:
Proximate dinoflagellate cyst with elongate ovoidal to spherical shape. Apex slightly pointed, occasionally with a short horn. Cyst wall two- layered, fibrous between endo- and periphragm. Surface of periphragm smooth, granulate, or finely reticulate.
Tabulation faintly expressed. Tabulation formula: 4`, 5a, 9``, 8c, 9```, 2p, 2````, 4s;
archaeopyle 3P3I.
Affinities:
Dodekovia differs from Tectatodinium Wall 1967 in archaeopyle formation (P3 in Tectatodinium). Dodekovia resembles Cribroperidinium; however, the latter has a different paratabulation (no anterior intercalary plates, Eaton 1976), is much larger, and has a long apical horn. A common feature in Dodekovia is the presence of sutural traces on the operculum. Apteodinium normally lacks tabulation and has a P3 archaeopyle. Gocht (1970: pl.34, figs.25-29) figured several specimens from the Bathonian of Germany as indeterminate genera, which most probably represent specimens of Dodekovia. The removal of one or two opercular pieces, each representing fused intercalary with precingular plates, are vestiges of the desintegration archaeopyle.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description:
Below, 1987: (Translation: Fensome et al., 1991, p. 182):
Diagnosis:
Arrangement of vesicles/plates on the dinoflagellate amphiessma 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 peridinoidal.
Cystic habit proximate, proximochorate, chorate, spheroidal, guttiform, ovoidal, ovaloidal, ellipsoidal, rarely peridinoidal, poles rounded or with apical horn and 1-2 antapical protruberances, equatorial cross section usually circular or oval, acavate, cavate; size variable; wall composed of pedium only, or pedium with usually rigid, prismatic-fibrose luxuria, luxuria forming tegillum and tectum; surface glabrous, ornamented, areate, nonareate; areation marked by finate or intraareate ornaments, limbi or intraareate protruberances; areation formula NR PR/cop, pop, cap, NR`/5`, NRa/3a, NR``/7``-6``, NRc/Xc/7c, NR```/5```, NR````/2````, NRs/Xs/as, x, y, z, ps; archaeopyle anterior intercalary, 2a; operculum monoareate, secate, opercular formula 2a(s).
Affinities:
Dörhöfer and Davies` (1980) diagnosis of the monotypic genus Dodekovia stipulates an areation of 4`, 5a, 9``, 8c, 9```, 2p, 2````, 4s and a type 3P3I archaeopyle. This areation formula and the arrangement of areae and archaeopyle presented by Dörhöfer and Davies (1980, fig.10) definitely are not supported by SEM investigations of the type species Dodekovia syzygia. Instead, areate specimens of this species show the typical pattern cop, pop, cap, 5`, 3a, 7``-6``, 7c, 5```, 2````, ns. The archaeopyle is monoareate and anterior intercalary, 2a(s).
Ovalicysta hiata Bjærke 1980, the type species of the genus Ovalicysta, is synonymous with Dodekovia syzygia, so that this genus must be absorbed. However, the same applies to the genera Susadinium Dörhöfer and Davies 1980 and parvocyst Bjærke 1980. Morphologically the typespecies of these three genera are very different. Dodekovia syzygia has a guttiform habit, Parvocysta bullula a peridinoidal habit, and Susadinium scrofoides strikingly protruberant areae. There are also differences in the wall structure. Dodekovia syzygia has a thick wall composed of pedium and spongy-prismatic luxuria, whereas both Parvocysta bullula and Susadinium scrofoides form only a thin, glabrous or scabrate peddium. However, material from the Toarcian and Aalenian contains numerous morphological transitional forms which mediate between the extremes and prove their taxonomic affinity. The series of variants will be fully outlined here.
1. Dodekovia syzygia, wall composed of pedium and spongy prismatic luxuria, surface smooth, habit guttiform, small apical horn.
1a: variation of Dodekovia: formation of a tegillum through distal fusion of the luxuriate fibrils leads to a variant with a continuous inner and outer "envelope" (pedium and tegilum, connected by fibrils; Evitt`s "differentiated autophragm".
1b: reduction of the filling between pedium and tegillum transforms the tegillum into a free tectum above the pedium, still connected with the pedium only locally. The cyst is then cavate between the endoblast and the periblast; if its habit is also changed in the process from guttiform to typically peridinoidal with a reniform, lenticular equatorial cross section, this leads over into taxa of the genus Moesiodinium.
2. Dodekovia syzygia.
2a: modification of the habit to oval or spheroidal taxa without apical protruberances, nonareate, but with the wall still composed of pedium and prismatic luxuria; Dodekovia pseudochytroides, Dodekovia reiculata.
3. Dodekovia syzygia.
3a: areae demarcated by means of luxuria of different thickness, and thus by areae protruberances of different prominence (Dodekovia pinna).
4. Dodekovia pinna.
4a: reduction of limbate luxuria so that intraareate luxuria becomes distinctly protruberant like an elevation, separated by finate septa (Dodekovia tabulata).
4b: complete reduction of areate luxuria, cyst consisting of pedium and finate luxuriate septa, variant of Dodekovia tabulata.
4c: extensive reduction of areae, pedium with traces of finate luxuria (variant of Dodekovia tabulata).
5. Whereas in Dodeekovia pinna and Dodekovia tabulata area protruberances are formed only by ornaments off the luxuria, in the next group the entire cyst wall with the exception of the cingulum forms sometimes very striking angular protrusions tracing the area outlines (Dodekovia knertensis).
5a: luxuriate ornaments only on rounded intraareate pedium prorubrenaces (Dodekovia scrofoides var. penicillus).
5b: complete reduction of luxuria, slight dorsoventral flattening (Dodekovia scrofoides var. scrofoides).
5c: Severe dorsoventral flattening into a peridinoidal habit, and drastic reduction of area protruberances leads over to the structure of Dodekovia bullula. However, perhaps this structure can also be derived through reduction of the tectum from the peridinoidal structure of Moesiodinium?
Reutlingia has a monoareate, adnate operculum 2a. Moesiodinium is cavate and has a peridinoidal habit, and Pyxidiella Cookson and Eisenack, 1958 is elongate, cylindroform.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Stover and Williams, 1987, p. 87:
Remarks:
Examination of specimens of the type species of Dodekovia, D. syzygia, filed to reveal evidence for the elaborate and complex paratabulation scheme presented in Dörhöfer and Davies, 1980 (fig.11). The holotype (and best preserved specimen of the types) appears to be a relatively uncomplicated, subspherical cyst with a short apical protrusion and a simple, middorsal, precingular (3``) archaeopyle. Indications of paratabulation, other than the archaeopyle, are lacking. It is on the basis of these observations that the new combination, Apteodinium syzygium, is made.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Dodekovia Dörhöfer and Davies, 1980, emend. Below, 1987a. From Feist-Burkhardt (1995), This genus has a type I archeopyle with a free operculum. Feist-Burkhardt follows Below (1987) in considering it to be the taxonomic senior synonym of Ovalicysta, Parvocysta and Susadinium .