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Seriliodinium imperfecta
From Fensome et al., 2019:
Seriliodinium imperfectum Soliman and Riding, 2017, p.336, 340, pl.6, figs.1–13. Holotype: Soliman and Riding, 2017, pl.6,
figs.4–6 (not pl.3, figs.4–6 as indicated under the heading "holotype" on p.336). Questionable assignment: Soliman
and Riding, 2017, p.336. Age. Late Miocene
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Original description Soliman and Riding, 2017:
Holotype. Sample HC1-11, slide A, England-Finder coordinate S35/0 (Plate III, 4–6). Specimen number UMJ GandP 211336 of the Joanneum Museum, Graz, Austria.
Paratype. Sample F1, slide A, England-Finder coordinate G28/0 (Plate III, 1–3).
Etymology. From the Latin imperfecta, meaning incomplete, with reference to the incomplete trabeculae.
Type locality. Hennersdorf Clay Pit, Vienna Basin, Austria.
Lithostratigraphy of the type material. The Záhorie Member of the Bzenec Formation, Upper Miocene (Pannonian).
Diagnosis. Semitrabeculate chorate dinoflagellate cysts with an ovoidal to subcircular cyst body. The cyst wall is thin with a scabrate to finely granulate surface. A prominent apical boss is generally present (Plate VI, 6). Processes are gonal, distally trifurcate and, at the cingulum, are distally multifurcate. Low sutural ridges/septa indicating a gonyaulacacean tabulation are variably developed these are highest at the cingulum and may be entirely absent. Some processes may be linked distally by rope-like trabeculae. The archaeopyle is precingular (type P), and the operculum is free.
Description. Seriliodinium? imperfecta sp. nov. is a medium-sized chorate cyst which is ovoidal or rarely subcircular in overall outline. The cyst wall is thin (~ l μm) with a scabrate to finely granulate surface. The sutural ridges are of variable height, but are normally highest equatorially. A prominent (2–6 μm) apical boss is generally developed. The gonal processes are solid, subcircular to triangular in cross-section, expanded distally and trifurcate. These trifurcations are either isolated or connected distally by rope-like trabeculae. Occasionally, the processes may have some proximal perforations (Plate VI, 13) and the processes are branched medially to distally. The cingular processes are distally multifurcate which a give a fenestrate appearance; they may be distally connected by trabeculae. Trabeculae, if present, are single and smooth. A standard gonyaulacean tabulation (4′, 6″, 6c, 6‴, lp, 1″″) is expressed by the sutural ridges and the distal trabeculae. The cingulum is indicated by two rows of parallel processes connected proximally by sutural ridges (Plate VI, 11). The archaeopyle is precingular (type P) with a free operculum.
Comments. Seriliodinium? imperfecta sp. nov. is characterised by its spiniferate process architecture, the gonyaulacacean tabulation and a discontinuous distal rope-like trabeculum. It is questionably attributed to Seriliodinium because of the incomplete trabeculum. Seriliodinium? imperfecta is trabeculate and marginate so it is much more closer to Seriliodinium than to Spiniferites. It cannot be Spiniferites as there are no sutures. But also Seriliodinium has sutures. The closest genus is thus Seriliodinium, but the lack of sutures mean that it is questionably assigned to this genus. Additionally, it is not attributed to Nematosphaeropsis Deflandre and Cookson, 1955 because of the cyst body is oval with a small apical boss and incomplete trabeculae rather than folded, commonly, spherical to subspherical with complete penitabular pairs of ribbon-like trabeculae.
Comparison. Seriliodinium? imperfecta sp. nov. differs from Seriliodinium explicatum Eaton 1996 in having an apical boss, being ovoidal in outline rather than rounded cruciform and lacking complete trabeculae. Additionally, Seriliodinium explicatum has mid-ventral and mid-dorsal areas which are devoid of processes, which is not the case in Seriliodinium? imperfecta sp. nov. Seriliodinium? imperfecta sp. nov. resembles Spiniferites validus Sütőné-Szentai 1982 from the Late Pannonian of Hungary in the cyst outline and the presence of an apical boss. But the former differs in being significantly smaller than Spiniferites validus, and in having shorter and distally-connected processes. The shape and apical boss of Seriliodinium? imperfecta sp. nov. means that it is similar to species of Spiniferites from the Eastern Paratethys (e.g. Sütőné-Szentai, 2000, Sütőné-Szentai, 2002, Sütőné-Szentai, 2003, Sütőné-Szentai, 2004). However, the presences of the rope-like distal trabeculae distinguish it from all these taxa. Seriliodinium? imperfecta sp. nov. differs from Nematosphaeropsis by lacking complete penitabular pairs of ribbon-like trabeculae and from taxa belonging to Cannosphaeropsis by incomplete trabeculae. Spiniferites rhizophorus Head in Head and Westphal, 1999 resembles Seriliodinium? imperfecta sp. nov. in that some processes are supported by stilt-like columns but differs in that the processes are not connected distally by discontinuous rope-like trabeculae and it lacks an apical boss.
Dimensions. The length of the cyst body, including the apical boss, of the holotype is 47 μm; the equatorial width is 32 μm and the maximum length of the processes is 16 μm. Overall, the length of the cyst body, including the apical boss, is 41 (55) 74 μm; the equatorial width is 31 (40) 50 μm and the maximum length of the processes is 10–24 μm.
Distribution. Seriliodinium? imperfecta sp. nov. is present in the Middle Pannonian of the Hennersdorf Clay Pit, Vienna Basin, Austria.
Seriliodinium imperfectum Soliman and Riding, 2017, p.336, 340, pl.6, figs.1–13. Holotype: Soliman and Riding, 2017, pl.6,
figs.4–6 (not pl.3, figs.4–6 as indicated under the heading "holotype" on p.336). Questionable assignment: Soliman
and Riding, 2017, p.336. Age. Late Miocene
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Original description Soliman and Riding, 2017:
Holotype. Sample HC1-11, slide A, England-Finder coordinate S35/0 (Plate III, 4–6). Specimen number UMJ GandP 211336 of the Joanneum Museum, Graz, Austria.
Paratype. Sample F1, slide A, England-Finder coordinate G28/0 (Plate III, 1–3).
Etymology. From the Latin imperfecta, meaning incomplete, with reference to the incomplete trabeculae.
Type locality. Hennersdorf Clay Pit, Vienna Basin, Austria.
Lithostratigraphy of the type material. The Záhorie Member of the Bzenec Formation, Upper Miocene (Pannonian).
Diagnosis. Semitrabeculate chorate dinoflagellate cysts with an ovoidal to subcircular cyst body. The cyst wall is thin with a scabrate to finely granulate surface. A prominent apical boss is generally present (Plate VI, 6). Processes are gonal, distally trifurcate and, at the cingulum, are distally multifurcate. Low sutural ridges/septa indicating a gonyaulacacean tabulation are variably developed these are highest at the cingulum and may be entirely absent. Some processes may be linked distally by rope-like trabeculae. The archaeopyle is precingular (type P), and the operculum is free.
Description. Seriliodinium? imperfecta sp. nov. is a medium-sized chorate cyst which is ovoidal or rarely subcircular in overall outline. The cyst wall is thin (~ l μm) with a scabrate to finely granulate surface. The sutural ridges are of variable height, but are normally highest equatorially. A prominent (2–6 μm) apical boss is generally developed. The gonal processes are solid, subcircular to triangular in cross-section, expanded distally and trifurcate. These trifurcations are either isolated or connected distally by rope-like trabeculae. Occasionally, the processes may have some proximal perforations (Plate VI, 13) and the processes are branched medially to distally. The cingular processes are distally multifurcate which a give a fenestrate appearance; they may be distally connected by trabeculae. Trabeculae, if present, are single and smooth. A standard gonyaulacean tabulation (4′, 6″, 6c, 6‴, lp, 1″″) is expressed by the sutural ridges and the distal trabeculae. The cingulum is indicated by two rows of parallel processes connected proximally by sutural ridges (Plate VI, 11). The archaeopyle is precingular (type P) with a free operculum.
Comments. Seriliodinium? imperfecta sp. nov. is characterised by its spiniferate process architecture, the gonyaulacacean tabulation and a discontinuous distal rope-like trabeculum. It is questionably attributed to Seriliodinium because of the incomplete trabeculum. Seriliodinium? imperfecta is trabeculate and marginate so it is much more closer to Seriliodinium than to Spiniferites. It cannot be Spiniferites as there are no sutures. But also Seriliodinium has sutures. The closest genus is thus Seriliodinium, but the lack of sutures mean that it is questionably assigned to this genus. Additionally, it is not attributed to Nematosphaeropsis Deflandre and Cookson, 1955 because of the cyst body is oval with a small apical boss and incomplete trabeculae rather than folded, commonly, spherical to subspherical with complete penitabular pairs of ribbon-like trabeculae.
Comparison. Seriliodinium? imperfecta sp. nov. differs from Seriliodinium explicatum Eaton 1996 in having an apical boss, being ovoidal in outline rather than rounded cruciform and lacking complete trabeculae. Additionally, Seriliodinium explicatum has mid-ventral and mid-dorsal areas which are devoid of processes, which is not the case in Seriliodinium? imperfecta sp. nov. Seriliodinium? imperfecta sp. nov. resembles Spiniferites validus Sütőné-Szentai 1982 from the Late Pannonian of Hungary in the cyst outline and the presence of an apical boss. But the former differs in being significantly smaller than Spiniferites validus, and in having shorter and distally-connected processes. The shape and apical boss of Seriliodinium? imperfecta sp. nov. means that it is similar to species of Spiniferites from the Eastern Paratethys (e.g. Sütőné-Szentai, 2000, Sütőné-Szentai, 2002, Sütőné-Szentai, 2003, Sütőné-Szentai, 2004). However, the presences of the rope-like distal trabeculae distinguish it from all these taxa. Seriliodinium? imperfecta sp. nov. differs from Nematosphaeropsis by lacking complete penitabular pairs of ribbon-like trabeculae and from taxa belonging to Cannosphaeropsis by incomplete trabeculae. Spiniferites rhizophorus Head in Head and Westphal, 1999 resembles Seriliodinium? imperfecta sp. nov. in that some processes are supported by stilt-like columns but differs in that the processes are not connected distally by discontinuous rope-like trabeculae and it lacks an apical boss.
Dimensions. The length of the cyst body, including the apical boss, of the holotype is 47 μm; the equatorial width is 32 μm and the maximum length of the processes is 16 μm. Overall, the length of the cyst body, including the apical boss, is 41 (55) 74 μm; the equatorial width is 31 (40) 50 μm and the maximum length of the processes is 10–24 μm.
Distribution. Seriliodinium? imperfecta sp. nov. is present in the Middle Pannonian of the Hennersdorf Clay Pit, Vienna Basin, Austria.