Back
Eucladinium kaikourense
Eucladinium kaikourense Schiøler and Wilson, 1998 Plate 1, figs. 1-9
Holotype: Schiøler and Wilson, 1998 Plate 1, figs. 1-2
Paratypes: Schiøler and Wilson, 1998 Plate 1, Fig. 3, 6, 7, 8-9
Repository: The palynological type collection, Institute of Geological and Nuclear Sciences, Lower Hutt, New Zealand.
Type locality: Ben More section, south Marlborough, New Zealand.
Type stratum: Herring Formation at 179.5 m on log P30c6. Lower Haumurian (upper Santonian-lower Campanian.
Derivation of name: After the nearby Kaikoura Ranges (text-fig. 2).
Diagnosis: Circumcavate to bicavate, eggshaped to oval peridinioid cyst. Periphragm thick, smooth and ornamented with granulae near the apex. Endophragm thin, broader than long. A ring-shaped ridge runs on ventral side of the periphragm, sub-parallel to cyst ambitus, and starts and ends close to apex. Paracingulum faintly indicated by an equatorial indentation on ambitus and an equatorial fold on dorsal side of periphragm. Periarcheopyle intercalary, type I, iso- to lati-deltaform, endoarcheopyle intercalary, type 3I.
Description: Circumcavate to bicavate egg-shaped to oval peridinioid cyst. The apex often has a low protrusion, the antapical part of the cyst is slightly asymmetrical, indicating the presence of a left antapical bulge. The periphragm is thick (1-2 µm), hyaline and smooth except in the apical area, where it is ornamented with granulae (diameter of granulae: 1-2 µm). The granulation is concentrated in the upper part of the cyst, but typically extends at least half way down to the paracingulum, giving the epicyst a serrate outline. A low wart-like tubercle is almost always present at the apex (diameter of tubercle: 2-4 µm). The hypocyst typically lacks granulation. The endocyst is thin (<0.5 µm), subspherical to oval and wider than long. The endocyst is located closer to the antapex than to the apex. In most specimens the endophragm is not in contact with the periphragm equatorially, and the cyst is circumcavate, occasionally the endophragm touches the periphragm equatorially, and the cyst is bicavate with an epicoel larger than the hypocoel. A ridge-shaped thickening originates close to the apical tubercle on the ventral side and runs parallel to the cyst outline towards the antapex. Ridge thickness: 1-5 µm. The ridge usually fades out in the vicinity of the antapex. In a number of specimens a similar structure was observed on the dorsal side, originating close to the paracingulum and running towards the antapex (Plate 1, Fig. 1). The peri-archeopyle is type I, iso-deltaform and with a TAI of 0.36-0.40; the operculum is free. The archeopyle margin is usually marked by a thickening of the periphragm. The endoarcheopyle is type 3I, and apparently free (Plate 1, figs. 6, 9). The paracingulum is indicated by an equatorial indentation on the ambitus. The parasulcus is not indicated. The paratabulation is not indicated apart from the archeopyle and the paracingulum.
Dimensions (in µm):
holotyperange
Length of periphragm 92 75 (91) 98
Width of periphragm 80 69 (81) 89
Length of endophragm 42 36 (50) 60
Width of endophragm 66 66 (80) 86
Number of specimens measured: 10
Stratigraphic occurrence: 172.5-196.5 m in the Ben More section. Upper Piripauan-lower Haumurian (middle-upper Santonian, Upper Cretaceous) in the lower Herring Formation, south Marlborough, New Zealand.
Remarks: The new species differs from the three other species in the genus; Eucladinium gambangense (Cookson and Eisenack, 1970) Stover and Evitt, 1978, Eucladinium madurense (Cookson and Eisenack, 1970) Stover and Evitt, 1978 and Eucladinium spinosissimum (Cookson and Eisenack, 1970) Stover and Evitt, 1978 by having a ring-shaped ornament on the ventral surface. Eucladinium cf. madurense of Keating, 1992 resembles the new species, but lacks the ring-shaped ventral ornament, judged from the illustrated specimens.
Mao and Mohr (1992) established the genus Abratopdinium to encompass circumcavate peridinioid cysts with circular to heart-like outline and thin, hyaline peri- and endophragm. The species Abratopdinium kerguelense Mao and Mohr, 1992 is characterized by its spherical to subspherical shape, and some specimens were noted to have a fold running parallel to the cyst ambitus. A figured specimen clearly shows this feature (Mao and Mohr, 1992, plate 1, fig. 6) and closely resembles Eucladinium kaikourense sp. nov.; if the fold can be proven to be a ventrally positioned ridge, the figured specimen may be conspecific with Eucladinium kaikourense sp. nov.
Holotype: Schiøler and Wilson, 1998 Plate 1, figs. 1-2
Paratypes: Schiøler and Wilson, 1998 Plate 1, Fig. 3, 6, 7, 8-9
Repository: The palynological type collection, Institute of Geological and Nuclear Sciences, Lower Hutt, New Zealand.
Type locality: Ben More section, south Marlborough, New Zealand.
Type stratum: Herring Formation at 179.5 m on log P30c6. Lower Haumurian (upper Santonian-lower Campanian.
Derivation of name: After the nearby Kaikoura Ranges (text-fig. 2).
Diagnosis: Circumcavate to bicavate, eggshaped to oval peridinioid cyst. Periphragm thick, smooth and ornamented with granulae near the apex. Endophragm thin, broader than long. A ring-shaped ridge runs on ventral side of the periphragm, sub-parallel to cyst ambitus, and starts and ends close to apex. Paracingulum faintly indicated by an equatorial indentation on ambitus and an equatorial fold on dorsal side of periphragm. Periarcheopyle intercalary, type I, iso- to lati-deltaform, endoarcheopyle intercalary, type 3I.
Description: Circumcavate to bicavate egg-shaped to oval peridinioid cyst. The apex often has a low protrusion, the antapical part of the cyst is slightly asymmetrical, indicating the presence of a left antapical bulge. The periphragm is thick (1-2 µm), hyaline and smooth except in the apical area, where it is ornamented with granulae (diameter of granulae: 1-2 µm). The granulation is concentrated in the upper part of the cyst, but typically extends at least half way down to the paracingulum, giving the epicyst a serrate outline. A low wart-like tubercle is almost always present at the apex (diameter of tubercle: 2-4 µm). The hypocyst typically lacks granulation. The endocyst is thin (<0.5 µm), subspherical to oval and wider than long. The endocyst is located closer to the antapex than to the apex. In most specimens the endophragm is not in contact with the periphragm equatorially, and the cyst is circumcavate, occasionally the endophragm touches the periphragm equatorially, and the cyst is bicavate with an epicoel larger than the hypocoel. A ridge-shaped thickening originates close to the apical tubercle on the ventral side and runs parallel to the cyst outline towards the antapex. Ridge thickness: 1-5 µm. The ridge usually fades out in the vicinity of the antapex. In a number of specimens a similar structure was observed on the dorsal side, originating close to the paracingulum and running towards the antapex (Plate 1, Fig. 1). The peri-archeopyle is type I, iso-deltaform and with a TAI of 0.36-0.40; the operculum is free. The archeopyle margin is usually marked by a thickening of the periphragm. The endoarcheopyle is type 3I, and apparently free (Plate 1, figs. 6, 9). The paracingulum is indicated by an equatorial indentation on the ambitus. The parasulcus is not indicated. The paratabulation is not indicated apart from the archeopyle and the paracingulum.
Dimensions (in µm):
holotyperange
Length of periphragm 92 75 (91) 98
Width of periphragm 80 69 (81) 89
Length of endophragm 42 36 (50) 60
Width of endophragm 66 66 (80) 86
Number of specimens measured: 10
Stratigraphic occurrence: 172.5-196.5 m in the Ben More section. Upper Piripauan-lower Haumurian (middle-upper Santonian, Upper Cretaceous) in the lower Herring Formation, south Marlborough, New Zealand.
Remarks: The new species differs from the three other species in the genus; Eucladinium gambangense (Cookson and Eisenack, 1970) Stover and Evitt, 1978, Eucladinium madurense (Cookson and Eisenack, 1970) Stover and Evitt, 1978 and Eucladinium spinosissimum (Cookson and Eisenack, 1970) Stover and Evitt, 1978 by having a ring-shaped ornament on the ventral surface. Eucladinium cf. madurense of Keating, 1992 resembles the new species, but lacks the ring-shaped ventral ornament, judged from the illustrated specimens.
Mao and Mohr (1992) established the genus Abratopdinium to encompass circumcavate peridinioid cysts with circular to heart-like outline and thin, hyaline peri- and endophragm. The species Abratopdinium kerguelense Mao and Mohr, 1992 is characterized by its spherical to subspherical shape, and some specimens were noted to have a fold running parallel to the cyst ambitus. A figured specimen clearly shows this feature (Mao and Mohr, 1992, plate 1, fig. 6) and closely resembles Eucladinium kaikourense sp. nov.; if the fold can be proven to be a ventrally positioned ridge, the figured specimen may be conspecific with Eucladinium kaikourense sp. nov.