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Sentusidinium devonense
Sentusidinium devonense sp. nov. , Pearce, M. A., 2018, p. 80
Holotype: Pearce, M. A., 2018, Pl. 4, figs. 1–3. (MPK 14634, EF coordinates: O17,)
Type locality and horizon: Middle Chalk Formation, New Pit Chalk Member, Terebratulina lata Zone
Stratigraphic range: Middle Turonian to Lower Coniacian
Original description: Pearce, M. A., 2018:
Diagnosis:
A species of Sentusidinium with an even covering of short, flexuous and acuminate spines.
Description:
A medium-sized proximate dinoflagellate cyst with a sub-rounded body.
Wall: is composed of a finely granular autophragm that possesses short (∼ 2 μm), evenly distributed and apparently solid, simple flexuous spines with acuminate tips.
No expression of the cingulum or sulcus is present.
Archaeopyle: is apical, Type tA, with a zig-zag margin and clear accessory sutures
Operculum: may be attached but more usually detached.
Dimensions:
Holotype, central body w/ l (excluding operculum) = 66 × 43 μm, maximum process length 2 μm;
paratype 1: central body w/ l (excluding operculum) = 65 × 48 μm, maximum process length 2 μm;
paratype 2: central body w/ l = 68 × 50 μm, maximum process length 2 μm;
paratype 3: central body w/ l = 60 × 50 μm, maximum process length 3 μm.
Range, central body w/ l (excluding operculum) = 40(61)76 × 40(48)60 μm, maximum process length = 2(2)3 μm.
Seventeen specimens measured.
Remarks:
FitzPatrick (1995) described the informal species Canningia sp. B from the Turonian of Southern England. She considered the generic attribution based on the subspherical outline, non-tabular spinose ornament and apical archaeopyle; however, she also mentioned the lack of an offset sulcal notch. These observations suggest that the species is not an areoligeracean, and that it has a greater affinity with Sentusidinium, and it is here considered synonymous with S. devonense sp. nov.
Affinities/Comparison:
All comparable species differ in the shape of the central body and/or the morphology of the processes. Sentusidinium aptiense (Burger, 1980a) Burger, 1980b possesses hollow tubular spines and S. capillatum (Davey, 1975) Lentin and Williams, 1981, S. echinatum (Gitmez and Sarjeant, 1972) Sarjeant and Stover, 1978 and S? millepiedii (Jain and Millepied, 1975) Islam, 1993 possesses much more densely distributed ornament. Sentusidinium capitatum (Cookson and Eisenack, 1960) Wood et al., 2016 may possess short spines with acuminate tips but the body is distinctly elongate, while S. minus (Jiabo, 1978) He et al. in He et al., 1989 is significantly smaller. Sentusidinium myriatrichum Fensome, 1979 possesses significantly shorter and denser ornament and S. perforoconum (Yun Hyesu, 1981) Islam, 1993 has a densely perforate periphragm. Sentusidinium pilosum (Ehrenberg, 1854) Sarjeant and Stover, 1978 has a denser cover of short processes with variable tips that are also variable in S. rioultii Sarjeant, 1968, S. sahii (Khanna and Singh, 1981) Wood et al., 2016, S. sparsibarbatum Erkmen and Sarjeant, 1980 and S. villersense (Sarjeant, 1968) Sarjeant and Stover, 1978. Sentusidinium separatum (McIntyre and Brideaux, 1980) Lentin and Williams, 1981 has bifid and branched process tips.
Holotype: Pearce, M. A., 2018, Pl. 4, figs. 1–3. (MPK 14634, EF coordinates: O17,)
Type locality and horizon: Middle Chalk Formation, New Pit Chalk Member, Terebratulina lata Zone
Stratigraphic range: Middle Turonian to Lower Coniacian
Original description: Pearce, M. A., 2018:
Diagnosis:
A species of Sentusidinium with an even covering of short, flexuous and acuminate spines.
Description:
A medium-sized proximate dinoflagellate cyst with a sub-rounded body.
Wall: is composed of a finely granular autophragm that possesses short (∼ 2 μm), evenly distributed and apparently solid, simple flexuous spines with acuminate tips.
No expression of the cingulum or sulcus is present.
Archaeopyle: is apical, Type tA, with a zig-zag margin and clear accessory sutures
Operculum: may be attached but more usually detached.
Dimensions:
Holotype, central body w/ l (excluding operculum) = 66 × 43 μm, maximum process length 2 μm;
paratype 1: central body w/ l (excluding operculum) = 65 × 48 μm, maximum process length 2 μm;
paratype 2: central body w/ l = 68 × 50 μm, maximum process length 2 μm;
paratype 3: central body w/ l = 60 × 50 μm, maximum process length 3 μm.
Range, central body w/ l (excluding operculum) = 40(61)76 × 40(48)60 μm, maximum process length = 2(2)3 μm.
Seventeen specimens measured.
Remarks:
FitzPatrick (1995) described the informal species Canningia sp. B from the Turonian of Southern England. She considered the generic attribution based on the subspherical outline, non-tabular spinose ornament and apical archaeopyle; however, she also mentioned the lack of an offset sulcal notch. These observations suggest that the species is not an areoligeracean, and that it has a greater affinity with Sentusidinium, and it is here considered synonymous with S. devonense sp. nov.
Affinities/Comparison:
All comparable species differ in the shape of the central body and/or the morphology of the processes. Sentusidinium aptiense (Burger, 1980a) Burger, 1980b possesses hollow tubular spines and S. capillatum (Davey, 1975) Lentin and Williams, 1981, S. echinatum (Gitmez and Sarjeant, 1972) Sarjeant and Stover, 1978 and S? millepiedii (Jain and Millepied, 1975) Islam, 1993 possesses much more densely distributed ornament. Sentusidinium capitatum (Cookson and Eisenack, 1960) Wood et al., 2016 may possess short spines with acuminate tips but the body is distinctly elongate, while S. minus (Jiabo, 1978) He et al. in He et al., 1989 is significantly smaller. Sentusidinium myriatrichum Fensome, 1979 possesses significantly shorter and denser ornament and S. perforoconum (Yun Hyesu, 1981) Islam, 1993 has a densely perforate periphragm. Sentusidinium pilosum (Ehrenberg, 1854) Sarjeant and Stover, 1978 has a denser cover of short processes with variable tips that are also variable in S. rioultii Sarjeant, 1968, S. sahii (Khanna and Singh, 1981) Wood et al., 2016, S. sparsibarbatum Erkmen and Sarjeant, 1980 and S. villersense (Sarjeant, 1968) Sarjeant and Stover, 1978. Sentusidinium separatum (McIntyre and Brideaux, 1980) Lentin and Williams, 1981 has bifid and branched process tips.