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Exochosphaeridium alisitosense
Exochophaeridium alisitosense Helenes, 2000, p.140, pl.1, figs.1-14,17-18; pl.2, figs.1-20; text-fig.3a-d. Holotype: Helenes, 2000, pl.1, figs.1-4.
Age: Late Albian.
Original description (Helenes, 2000)
Derivation of name: The specific epithet refers to the Alisitos Formation, a stratigraphic unit from Baja California, where the holotype was found.
Holotype: Plate I, figures 1-4. The holotype is located at the Laboratory of Palynology and Micropaleontology at CICESE, Baja California, Mexico. Slide Num. 5598C, coordinates 98.3-5.0; corrected to conform to the Vernier scales of the stage of Zeiss Photoscope (PL-2) at the same laboratory. The type specimen is surrounded by a circle engraved with a diamond ringer on the coverslip, and painted with purple ink, and surrounded by another purple circle under the slide. It is located at approximately I 8 millimeters to the left and 3 millimeters down from an X engraved with diamond, and painted with black ink, on the right side of the slide, just below the C. Paratypes: Plate 1, figures 5-6, 7. The paratypes are located at the same laboratory. Slide Num. 5598b, coordinates 119.1-11. 7 (PI. 1, figs. 5,6), and 101.6-11.2 (PI. 1, fig. 7); corrected to conform to the Vernier scales of the stage of Zeiss Photoscope (PL-2) at the same laboratory. They are both surrounded by circles engraved with a diamond ringer, and painted with purple ink.
Diagnosis: Subspherical, chorate acavate cysts with a weakly developed apical horn, and a precingular type P archeopyle. Intratabular to (less commonly) nontabular, simple, slightly fibrous spines. When discernable, the dorsal tabulation shows dextral torsion with postcingular parasuture IV IV (3"'/4"') approximately
middorsal in position. The antapical area is reticulated and lacks spines.
Detailed description: Subspherical central body with an average diameter of 45μm and with intratabular, solid processes or spines that are simple, acuminate to capitate, slightly fibrous and approximately I 5μm long. A short apical bulge (approxiapproximately 5μm) is present, and the antapical area is reticulated and lacks processes or spines except at the edges of the antapical paraplate Y (Kofoid l ""). The antapical paraplate and the adjacent paraplates together delineate a symmetrical sexiform arrangement with dextral torsion. This species presents an S-type ventral organization together with an Alai paratabulation pattern. The apical horn has intergonal spines that seem to indicate the presence of two preapical paraplates (P and Q). Size: Cingular diameter ranges from 45 to 60μm, height ranges from 50 to 70μm , length of processes or spines range from 5 to 20μm. Height of apical horn ranges from 3 to 10 μm.
Age: Late Albian.
Original description (Helenes, 2000)
Derivation of name: The specific epithet refers to the Alisitos Formation, a stratigraphic unit from Baja California, where the holotype was found.
Holotype: Plate I, figures 1-4. The holotype is located at the Laboratory of Palynology and Micropaleontology at CICESE, Baja California, Mexico. Slide Num. 5598C, coordinates 98.3-5.0; corrected to conform to the Vernier scales of the stage of Zeiss Photoscope (PL-2) at the same laboratory. The type specimen is surrounded by a circle engraved with a diamond ringer on the coverslip, and painted with purple ink, and surrounded by another purple circle under the slide. It is located at approximately I 8 millimeters to the left and 3 millimeters down from an X engraved with diamond, and painted with black ink, on the right side of the slide, just below the C. Paratypes: Plate 1, figures 5-6, 7. The paratypes are located at the same laboratory. Slide Num. 5598b, coordinates 119.1-11. 7 (PI. 1, figs. 5,6), and 101.6-11.2 (PI. 1, fig. 7); corrected to conform to the Vernier scales of the stage of Zeiss Photoscope (PL-2) at the same laboratory. They are both surrounded by circles engraved with a diamond ringer, and painted with purple ink.
Diagnosis: Subspherical, chorate acavate cysts with a weakly developed apical horn, and a precingular type P archeopyle. Intratabular to (less commonly) nontabular, simple, slightly fibrous spines. When discernable, the dorsal tabulation shows dextral torsion with postcingular parasuture IV IV (3"'/4"') approximately
middorsal in position. The antapical area is reticulated and lacks spines.
Detailed description: Subspherical central body with an average diameter of 45μm and with intratabular, solid processes or spines that are simple, acuminate to capitate, slightly fibrous and approximately I 5μm long. A short apical bulge (approxiapproximately 5μm) is present, and the antapical area is reticulated and lacks processes or spines except at the edges of the antapical paraplate Y (Kofoid l ""). The antapical paraplate and the adjacent paraplates together delineate a symmetrical sexiform arrangement with dextral torsion. This species presents an S-type ventral organization together with an Alai paratabulation pattern. The apical horn has intergonal spines that seem to indicate the presence of two preapical paraplates (P and Q). Size: Cingular diameter ranges from 45 to 60μm, height ranges from 50 to 70μm , length of processes or spines range from 5 to 20μm. Height of apical horn ranges from 3 to 10 μm.