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Dodekovia scrofoides
Dodekovia scrofoides (Dörhöfer and Davies, 1980) emend. Below, 1987
Now Susadinium. Originally (and now) Susadinium, subsequently Dodekovia.
Tax. sr. synonym of Parvocysta contracta Bjaerke, 1980, according to Below, 1987.
Lentin and Williams, 1989, retained this species in Susadinium D÷rh÷fer and Davies, 1980.
At the time of the transfer, Below, 1987, emended the diagnosis of the autonym of this species, as Dodekovia scrofoides var. scrofoides.
Holotype: Dörhöfer and Davies, 1980, fig. 24I
Locus typicus: Savik Formation, Reindeer Peninsula, Ellef Ringnes Island, Sverdrup Basin, Arctic Canada.
Stratum typicum: Toarcian-Bathonian
Translation Below, 1987: Secretary of State, Canada, Bureau of translation, p. 300-301
Original description: D÷rh÷fer and Davies, 1980, p. 28-29: Susadinium scrofoides
Diagnosis: A species of Susadinium with a short apical horn and rounded to angular intratabular protuberances in the pre- and postcingular plate series. Autophragm thin, smooth to granulate. Cingulum and sulcus broad. Tabulation 4", 5a, 6"", ?6c, 5""", ?1"""". Archeopyle 3I(plates 2-4).
Remarks: Autoblast often dorsoventrally compressed. The precingular series consists of five short rounded protuberances, the postcingular of three short dorsal and two larger bulging ventral protuberances flanking the sulcus. The apical horn is often sharply pointed with an apical angle of 35-40 degrees. Sutural granules sometimes delimit the apical plates and ventral cingular plates. The tabulation formula was obtained from plate sutures and intratabular protuberances.
The broad sulcal area might include additional plates of the pre- and postcingular series, which are not provided with intratabular protuberances. Cantulodinium protuberatum Wall, 1965 superficially resembles S. scrofoides, but due to its inadequate description and illustration closer comparisons are not possible. Length 29(38)42 Ám; width 19(22)26 Ám.
Emended description: Below, 1987a, p. 120: Dodekovia scrofoides var. scrofoides
Arrangement of vesicles/plates on the dinoflagellate amphiesma cop, pop, cap, 5", 3a, 7""-6"", 7c, 5""" 2"""", as, y, z, ps; 1"""" and 2"""" located symmetrically on either side of the dorsoventral plane.
Cystic habit proximate, acavate-apiculocavate, oblong ovaloidal, apically also conical to tentoriate, with a broad cingular constriction and rounded areate protuberances, protuberances reflecting 1""" and 2""" and 4""" and 5""" fused basally or completely into large, broad, dextro- or sinistrolateral evaginations, cyst oval to circular in equatorial cross section; size small; wall composed of pedium and luxuria; surface smooth, scabrate or granular, protuberances distally unornamented, very coarsely shagreen or with low baculi, ornaments peniareate laong the margins of protuberances or also intraareate, so that the contours of the homologous plates are not reflected, or exactly reflected, or schematically reflected by protuberances and their ornamentation, NRPR/XPR/cop, pop, cap, NR"/NR", X2", X3", X4", X5", NRa/X1a, 2a arch,, X3a, X1"", X2"", X3"", X4"", X5"", X6"", X7"", NRc, X1""", X2""", X3""", X4""", X5""", X1"""", X2"""". NRs;
- PR an undifferentiated cusp or nodular cop surrounded by annular pop, apical plates mirrored by a field of ornaments around the apex which is undifferentiated, always interrupted only ventrally or divided into 2", 3", 4", and 5", 1" not reflected; - 3 anterior intercalaries not marked by protuberances and seldom marked by ornaments, usually only an undifferentiated, glabrous sector; fastigiate or heptagonal shape of 2a determined by archaeopyle;
- 6-7 precingulars reflected by large protuberances circular or polyhedral in cross section;
- cingulum a planar or weakly laevo-rotatory, broad indentation without protuberances;
- of the five postcingular protuberances, the laterals are largely fused, large 1"""" (L) usually reduced, fused with 1"""" and 2"""" as a low protuberance or plane, ornamented or without ornaments, large 2"""" a protuberance displaced towards RL;
- sulcus undivided, lightly indented;
- archaeopyle anterior intercalary, 2a, with monoareate, secate operculum, opercular formula 2a(s).
Remarks (annotated): A typical specimen of this species with a scabrate surface and only slightly granular tips on the protuberances is shown on Plate 17, Fig. 3-6, 16. It originates from the type stratum of Parvocysta contracta and Facetodinium inflatum, both of which I believe to be synonyms of Dodekovia scrofoides, since these three taxa hardly differ morphologically. Such individuals with indistinct or lacking ornamentation allow us to determine only the number and position of the areae, but not the shape of the plates. However, that can be done with the variant Dodekovia scofoides var. penicillus, which is very frequent in the Toarcian-Bajocian strata of Central Europe, and in which the top of the protuberances is always granular to baculate (Plate 17, Fig. 1 and 2). It seems reasonable to interpret each protuberance, and especially the granular surfaces, as homologous with the primary growth regions of the corresponding thecal plates. If the granules fill the entire plateau, they are intraareate; if they are only marginal, they are exactly peniareate. The glabrous and only very indistinctly shagreen and deeply indented regions between the protuberances of a series or bordering the anterior intercalaries, apicals, and antapicals represent very broad limbi reflecting the incremental growth of the thecal plate. Many specimens are more or less completely surrounded by a membrane, which is usually adjusted to the characteristic morphology determined by the protuberances, as that shape shows through the membrane (Plate 18, fig. 4, 7). However, specimen S2-1805(K01)5/14 (Plate 18, fig. 5) and several other individuals are surrounded by a membrane with a typical peridinoidal habitat, which the protuberances merely touch or rupture. These membranes are smooth. On specimen S2-1805 (K01)5/14, very fine, finate grooves appear only locally, and the cingulum is indented.
This is reminiscent of the condition in which the pellicle of Suessia swabiana was preserved, only in that case the membrane was occasionally also areate (see p. 88). I interpret this phragmj as a pellicle (possibly also a mesospore), since it is independent of the cyst wall sensu stricto, i.e., it is not fused with it.
Now Susadinium. Originally (and now) Susadinium, subsequently Dodekovia.
Tax. sr. synonym of Parvocysta contracta Bjaerke, 1980, according to Below, 1987.
Lentin and Williams, 1989, retained this species in Susadinium D÷rh÷fer and Davies, 1980.
At the time of the transfer, Below, 1987, emended the diagnosis of the autonym of this species, as Dodekovia scrofoides var. scrofoides.
Holotype: Dörhöfer and Davies, 1980, fig. 24I
Locus typicus: Savik Formation, Reindeer Peninsula, Ellef Ringnes Island, Sverdrup Basin, Arctic Canada.
Stratum typicum: Toarcian-Bathonian
Translation Below, 1987: Secretary of State, Canada, Bureau of translation, p. 300-301
Original description: D÷rh÷fer and Davies, 1980, p. 28-29: Susadinium scrofoides
Diagnosis: A species of Susadinium with a short apical horn and rounded to angular intratabular protuberances in the pre- and postcingular plate series. Autophragm thin, smooth to granulate. Cingulum and sulcus broad. Tabulation 4", 5a, 6"", ?6c, 5""", ?1"""". Archeopyle 3I(plates 2-4).
Remarks: Autoblast often dorsoventrally compressed. The precingular series consists of five short rounded protuberances, the postcingular of three short dorsal and two larger bulging ventral protuberances flanking the sulcus. The apical horn is often sharply pointed with an apical angle of 35-40 degrees. Sutural granules sometimes delimit the apical plates and ventral cingular plates. The tabulation formula was obtained from plate sutures and intratabular protuberances.
The broad sulcal area might include additional plates of the pre- and postcingular series, which are not provided with intratabular protuberances. Cantulodinium protuberatum Wall, 1965 superficially resembles S. scrofoides, but due to its inadequate description and illustration closer comparisons are not possible. Length 29(38)42 Ám; width 19(22)26 Ám.
Emended description: Below, 1987a, p. 120: Dodekovia scrofoides var. scrofoides
Arrangement of vesicles/plates on the dinoflagellate amphiesma cop, pop, cap, 5", 3a, 7""-6"", 7c, 5""" 2"""", as, y, z, ps; 1"""" and 2"""" located symmetrically on either side of the dorsoventral plane.
Cystic habit proximate, acavate-apiculocavate, oblong ovaloidal, apically also conical to tentoriate, with a broad cingular constriction and rounded areate protuberances, protuberances reflecting 1""" and 2""" and 4""" and 5""" fused basally or completely into large, broad, dextro- or sinistrolateral evaginations, cyst oval to circular in equatorial cross section; size small; wall composed of pedium and luxuria; surface smooth, scabrate or granular, protuberances distally unornamented, very coarsely shagreen or with low baculi, ornaments peniareate laong the margins of protuberances or also intraareate, so that the contours of the homologous plates are not reflected, or exactly reflected, or schematically reflected by protuberances and their ornamentation, NRPR/XPR/cop, pop, cap, NR"/NR", X2", X3", X4", X5", NRa/X1a, 2a arch,, X3a, X1"", X2"", X3"", X4"", X5"", X6"", X7"", NRc, X1""", X2""", X3""", X4""", X5""", X1"""", X2"""". NRs;
- PR an undifferentiated cusp or nodular cop surrounded by annular pop, apical plates mirrored by a field of ornaments around the apex which is undifferentiated, always interrupted only ventrally or divided into 2", 3", 4", and 5", 1" not reflected; - 3 anterior intercalaries not marked by protuberances and seldom marked by ornaments, usually only an undifferentiated, glabrous sector; fastigiate or heptagonal shape of 2a determined by archaeopyle;
- 6-7 precingulars reflected by large protuberances circular or polyhedral in cross section;
- cingulum a planar or weakly laevo-rotatory, broad indentation without protuberances;
- of the five postcingular protuberances, the laterals are largely fused, large 1"""" (L) usually reduced, fused with 1"""" and 2"""" as a low protuberance or plane, ornamented or without ornaments, large 2"""" a protuberance displaced towards RL;
- sulcus undivided, lightly indented;
- archaeopyle anterior intercalary, 2a, with monoareate, secate operculum, opercular formula 2a(s).
Remarks (annotated): A typical specimen of this species with a scabrate surface and only slightly granular tips on the protuberances is shown on Plate 17, Fig. 3-6, 16. It originates from the type stratum of Parvocysta contracta and Facetodinium inflatum, both of which I believe to be synonyms of Dodekovia scrofoides, since these three taxa hardly differ morphologically. Such individuals with indistinct or lacking ornamentation allow us to determine only the number and position of the areae, but not the shape of the plates. However, that can be done with the variant Dodekovia scofoides var. penicillus, which is very frequent in the Toarcian-Bajocian strata of Central Europe, and in which the top of the protuberances is always granular to baculate (Plate 17, Fig. 1 and 2). It seems reasonable to interpret each protuberance, and especially the granular surfaces, as homologous with the primary growth regions of the corresponding thecal plates. If the granules fill the entire plateau, they are intraareate; if they are only marginal, they are exactly peniareate. The glabrous and only very indistinctly shagreen and deeply indented regions between the protuberances of a series or bordering the anterior intercalaries, apicals, and antapicals represent very broad limbi reflecting the incremental growth of the thecal plate. Many specimens are more or less completely surrounded by a membrane, which is usually adjusted to the characteristic morphology determined by the protuberances, as that shape shows through the membrane (Plate 18, fig. 4, 7). However, specimen S2-1805(K01)5/14 (Plate 18, fig. 5) and several other individuals are surrounded by a membrane with a typical peridinoidal habitat, which the protuberances merely touch or rupture. These membranes are smooth. On specimen S2-1805 (K01)5/14, very fine, finate grooves appear only locally, and the cingulum is indented.
This is reminiscent of the condition in which the pellicle of Suessia swabiana was preserved, only in that case the membrane was occasionally also areate (see p. 88). I interpret this phragmj as a pellicle (possibly also a mesospore), since it is independent of the cyst wall sensu stricto, i.e., it is not fused with it.