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Xenascus ghanaensis
Xenascus ghanaensis Masure et al., 1998, p.266–267, pl.3, figs.14–15.
Holotype: Masure et al., 1998, pl.3, figs.14–15.
Age: Maastrichtian.
Original description (Masure et al., 1998)
Derivation of name: In connection with the geographical location of Leg 159, offshore Ghana.
Diagnosis: Dinoflagellate cysts proximochorate, circumcavate with ceratoid outline, with three prominent truncated horns; smooth endophragm, granulate periphragm with few short spines and processes arranged more or less parasuturally; archeopyle apical, type (tA), free polyplacoid operculum.
Holotype: Slide 2: U24, Sample 159-959D-57R-2, 12−15 cm.
Paratype 1: Slide 1: P37, Sample 159-959D-57R-2, 12−15 cm.
Paratype 2: Slide 2: W22, Sample 159-959D-57R-2, 12−15 cm.
Type locality: Hole 959D, offshore Ghana and Côte d’Ivoire, Côte d’Ivoire-Ghana Transform Margin.
Type biohorizon: Maastrichtian, 948.72 mbsf.
Housed: In the Centre Scientifique Georges Deflandre of the National Museum of Natural History in Paris, France.
Dimensions: Holotype: Total length 136 µm; epicyst, central body length 16 µm, apical horn length 36 µm, total length 52 µm; hypocyst length 84 µm.
Description: Shape: pericyst outline ceratioid, with prominent truncated horns, endocyst subspherical to ellipsoidal. Wall relationship: cyst circumcavate. Periphragm forms: one apical, one antapical, and one cingular horn, and a large pericoel around margin of central body in dorsoventral view. Wall features:
granulate periphragm, rare parasutural spines or processes on dorsal precingular and postcingular paraplates, on paracingular margins and on the apical horn; distal ends of truncated horns perforated; scabrate endophragm. Paratabulation: epicyst, principal archeopyle sutures indicate four apical paraplates
and six precingular paraplates; hypocyst, not determined. Paracingulum: indicated by cingular horn and alignment of rare processes or spines. Parasulcus: indicated anteriorly by the offset parasulcal notch. Archeopyle: apical type (tA), free polyplacoid operculum. Comparison: Xenascus ghanaensis n. sp. differs from other species of the genus in having a large pericoel around the margin of the central body in dorsoventral view and prominent truncated horns.
Occurrence: Hole 959D (see Fig. 2, number 35) from Sample 159-959D-57R-4, 114−117 cm (952.74 mbsf), to 56R-4, 60−62 cm (942.50 mbsf); Maastrichtian.
Holotype: Masure et al., 1998, pl.3, figs.14–15.
Age: Maastrichtian.
Original description (Masure et al., 1998)
Derivation of name: In connection with the geographical location of Leg 159, offshore Ghana.
Diagnosis: Dinoflagellate cysts proximochorate, circumcavate with ceratoid outline, with three prominent truncated horns; smooth endophragm, granulate periphragm with few short spines and processes arranged more or less parasuturally; archeopyle apical, type (tA), free polyplacoid operculum.
Holotype: Slide 2: U24, Sample 159-959D-57R-2, 12−15 cm.
Paratype 1: Slide 1: P37, Sample 159-959D-57R-2, 12−15 cm.
Paratype 2: Slide 2: W22, Sample 159-959D-57R-2, 12−15 cm.
Type locality: Hole 959D, offshore Ghana and Côte d’Ivoire, Côte d’Ivoire-Ghana Transform Margin.
Type biohorizon: Maastrichtian, 948.72 mbsf.
Housed: In the Centre Scientifique Georges Deflandre of the National Museum of Natural History in Paris, France.
Dimensions: Holotype: Total length 136 µm; epicyst, central body length 16 µm, apical horn length 36 µm, total length 52 µm; hypocyst length 84 µm.
Description: Shape: pericyst outline ceratioid, with prominent truncated horns, endocyst subspherical to ellipsoidal. Wall relationship: cyst circumcavate. Periphragm forms: one apical, one antapical, and one cingular horn, and a large pericoel around margin of central body in dorsoventral view. Wall features:
granulate periphragm, rare parasutural spines or processes on dorsal precingular and postcingular paraplates, on paracingular margins and on the apical horn; distal ends of truncated horns perforated; scabrate endophragm. Paratabulation: epicyst, principal archeopyle sutures indicate four apical paraplates
and six precingular paraplates; hypocyst, not determined. Paracingulum: indicated by cingular horn and alignment of rare processes or spines. Parasulcus: indicated anteriorly by the offset parasulcal notch. Archeopyle: apical type (tA), free polyplacoid operculum. Comparison: Xenascus ghanaensis n. sp. differs from other species of the genus in having a large pericoel around the margin of the central body in dorsoventral view and prominent truncated horns.
Occurrence: Hole 959D (see Fig. 2, number 35) from Sample 159-959D-57R-4, 114−117 cm (952.74 mbsf), to 56R-4, 60−62 cm (942.50 mbsf); Maastrichtian.