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Eurydinium tempestivum
Eurydinium tempestivum Mao Shaozhi and Norris, 1988
Holotype: Mao Shaozhi and Norris, 1988, pl.11, fig.17
Locus typicus: Kukebai Formation, Wuluokeqiate section, China
Stratum typicum: Turonian-Santonian
Original diagnosis: Mao Shaozhi and Norris, 1988, p. 44
Cyst proximate, circumcavate, subspherical, with strong convex sides. Apical horn small, prominent; either only left antapical horn or two antapical horns of unequal length developed; in either case, horn or horns typically small, pointed. Endoblast large, spherical, length commonly slightly greater than width and rarely equal with it. Wall thin, smooth to granulate. Cingulum expressed by folds or low ridges, not making an equatorial bulge in ambital view. Archeopyle intercalary, type (I), standard hexa 2a, transverse AI 0.41 to 0.5 (holotype 0.49 µm).
Original description: Mao Shaozhi and Norris, 1988, p. 44
Epitract triangular, two sides being more or less convex. Apical horn short (2.5 to 4 Ám high), bluntly pointed. Hypotract subtriangular to semicircular with one left antapical horn or trapezoid with two antapical horns, two sides typically straight or slightly convex, antapical margin straight or slightly concave. Antapical horn or horns small (2 to 4 Ám long), pointed, protruding from general outline; if two horns developed, left longer than right. Endoblast spherical to subellipsoidal, length slightly greater than width, occupying large portion of the pericoel, leaving 2-to-6-Ám-wide ambital and antapical pericoels. Cingulum planar or slightly levorotatory, delimited by wavy folds or low ridges, 4 to 6 Ám wide. Archeopyle standard hexa or superficially triangular because of lateral sides H2 and H6 being relatively longer than sides H3 and H5, and anterior margin H1 being considerably shorter than posterior margin H4. Sulcus not always discernible, restricted to hypotract. Dimensions: Overall: length 55 to 84 Ám (holotype 60 Ám), width 46 to 62.5 Ám (holotype 48 Ám); endoblast: length 40 to 60 Ám (holotype 40 Ám), width 38 to 53 Ám (holotype 38 Ám).
Affinities:
Mao Shaozhi and Norris, 1988, p. 44: Eurydinium tempestivum is characterized by its subspherical pericyst with a large spherical to broadly ellipsoidal endoblast, one short apical horn, and one or two small pointed antapical horns. It is closely comparable to E. ingramii, which has an elongate cyst with two sides less convex than the cyst of this species. Its ratio of length to width is 0.72 to 0.74, whereas that of E. tempestivum is 0.75 to 0.89. In addition, the antapical horn or horns of E. ingramii, when developed, are always distinct and pointed, no matter how small. E. tempestivum resembles Subtilisphaera foliacea but is readily differentiated from that species by its possession of a distinct intercalary archeopyle and a prominent apical horn. E. tempestivum is also similar to Deflandrea tribulosa, but the latter Tertiary species has two equally developed antapical horns.
Holotype: Mao Shaozhi and Norris, 1988, pl.11, fig.17
Locus typicus: Kukebai Formation, Wuluokeqiate section, China
Stratum typicum: Turonian-Santonian
Original diagnosis: Mao Shaozhi and Norris, 1988, p. 44
Cyst proximate, circumcavate, subspherical, with strong convex sides. Apical horn small, prominent; either only left antapical horn or two antapical horns of unequal length developed; in either case, horn or horns typically small, pointed. Endoblast large, spherical, length commonly slightly greater than width and rarely equal with it. Wall thin, smooth to granulate. Cingulum expressed by folds or low ridges, not making an equatorial bulge in ambital view. Archeopyle intercalary, type (I), standard hexa 2a, transverse AI 0.41 to 0.5 (holotype 0.49 µm).
Original description: Mao Shaozhi and Norris, 1988, p. 44
Epitract triangular, two sides being more or less convex. Apical horn short (2.5 to 4 Ám high), bluntly pointed. Hypotract subtriangular to semicircular with one left antapical horn or trapezoid with two antapical horns, two sides typically straight or slightly convex, antapical margin straight or slightly concave. Antapical horn or horns small (2 to 4 Ám long), pointed, protruding from general outline; if two horns developed, left longer than right. Endoblast spherical to subellipsoidal, length slightly greater than width, occupying large portion of the pericoel, leaving 2-to-6-Ám-wide ambital and antapical pericoels. Cingulum planar or slightly levorotatory, delimited by wavy folds or low ridges, 4 to 6 Ám wide. Archeopyle standard hexa or superficially triangular because of lateral sides H2 and H6 being relatively longer than sides H3 and H5, and anterior margin H1 being considerably shorter than posterior margin H4. Sulcus not always discernible, restricted to hypotract. Dimensions: Overall: length 55 to 84 Ám (holotype 60 Ám), width 46 to 62.5 Ám (holotype 48 Ám); endoblast: length 40 to 60 Ám (holotype 40 Ám), width 38 to 53 Ám (holotype 38 Ám).
Affinities:
Mao Shaozhi and Norris, 1988, p. 44: Eurydinium tempestivum is characterized by its subspherical pericyst with a large spherical to broadly ellipsoidal endoblast, one short apical horn, and one or two small pointed antapical horns. It is closely comparable to E. ingramii, which has an elongate cyst with two sides less convex than the cyst of this species. Its ratio of length to width is 0.72 to 0.74, whereas that of E. tempestivum is 0.75 to 0.89. In addition, the antapical horn or horns of E. ingramii, when developed, are always distinct and pointed, no matter how small. E. tempestivum resembles Subtilisphaera foliacea but is readily differentiated from that species by its possession of a distinct intercalary archeopyle and a prominent apical horn. E. tempestivum is also similar to Deflandrea tribulosa, but the latter Tertiary species has two equally developed antapical horns.