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Spinidinium selandicum
Spinidinium selandicum sp. nov., Vieira et al., 2020
Holotype: Plate III, 1
Age: Selandian Stage of Paleocene
Locality: Foinaven and Schiehallion Fields
Original description: Vieira et al., 2020:
Diagnosis:
Small to intermediate size, cornucavate peridinioid dinoflagellate cyst. Cyst exhibits a short blunt apical horn and one or two barely developed unequal antapical horns. Endocyst and pericyst are circular to pentagonal in overall shape. The endophragm is thin, psilate and a thin periphragm is noted bearing numerous short, blunt spines.
Description:
Proximate peridiniacean, cornucavate dinoflagellate cyst of small to intermediate size, with a very short blunt apical horn and one or two barely developed unequal antapical horns. Central body is usually dorsoventrally compressed.
Archeopyle: rarely discernible, but when visible it is of intercalary Type I (2a)
Operculum: often attached
Wall and processes: The dinoflagellate cyst has two layers closely adpressed except at the apex and possibly at the antapex where a pericoel may be present. Endophragm and periphragm are thin and smooth. Low sutural ridges are present which carry numerous thin, short, pale spines with acuminate, oblate or capitate tips. These spines more prominent in the dorsoventral view. The length of the processes rarely exceeds 3–4 μm. Surface ornament is arranged in penitabular rows or intratabular clusters.
Dimensions:
Central body length 49(60)68 μm, width 45(52)56 μm, process length 2(3)4 μm, length of apical horn 4(6)10 μm.
14 specimens measured
Remarks:
The unusual delicate ornamentation and very low sutural ridge observed in this species distinguishes it from other species in the genus such as Spinidinium essoi Cookson and Eisenack (1967), Spinidinium pulchrum (Benson, 1976) Lentin and Williams, 1977, Spinidinium macmurdoense (Wilson 1967) Lentin and Williams (1976) and Spinidinium? clavum Harland (1973). Vozzhennikovia tawannuiensis Crouch et al., 2014 differs from the present species in lacking the apical horn, having slightly denser and longer ornament and no evidence of sutural spines.
Holotype: Plate III, 1
Age: Selandian Stage of Paleocene
Locality: Foinaven and Schiehallion Fields
Original description: Vieira et al., 2020:
Diagnosis:
Small to intermediate size, cornucavate peridinioid dinoflagellate cyst. Cyst exhibits a short blunt apical horn and one or two barely developed unequal antapical horns. Endocyst and pericyst are circular to pentagonal in overall shape. The endophragm is thin, psilate and a thin periphragm is noted bearing numerous short, blunt spines.
Description:
Proximate peridiniacean, cornucavate dinoflagellate cyst of small to intermediate size, with a very short blunt apical horn and one or two barely developed unequal antapical horns. Central body is usually dorsoventrally compressed.
Archeopyle: rarely discernible, but when visible it is of intercalary Type I (2a)
Operculum: often attached
Wall and processes: The dinoflagellate cyst has two layers closely adpressed except at the apex and possibly at the antapex where a pericoel may be present. Endophragm and periphragm are thin and smooth. Low sutural ridges are present which carry numerous thin, short, pale spines with acuminate, oblate or capitate tips. These spines more prominent in the dorsoventral view. The length of the processes rarely exceeds 3–4 μm. Surface ornament is arranged in penitabular rows or intratabular clusters.
Dimensions:
Central body length 49(60)68 μm, width 45(52)56 μm, process length 2(3)4 μm, length of apical horn 4(6)10 μm.
14 specimens measured
Remarks:
The unusual delicate ornamentation and very low sutural ridge observed in this species distinguishes it from other species in the genus such as Spinidinium essoi Cookson and Eisenack (1967), Spinidinium pulchrum (Benson, 1976) Lentin and Williams, 1977, Spinidinium macmurdoense (Wilson 1967) Lentin and Williams (1976) and Spinidinium? clavum Harland (1973). Vozzhennikovia tawannuiensis Crouch et al., 2014 differs from the present species in lacking the apical horn, having slightly denser and longer ornament and no evidence of sutural spines.