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Rhombodinium intermedium
Rhombodinium "intermedium" (Cookson and Eisenack, 1961b, p.40, pl.1, figs.5–6) Lentin and Williams, 1973, p.120. Holotype: Cookson and Eisenack, 1961b, pl.1, fig.5. NOW Castellodinium. Originally Wetzeliella, subsequently Rhombodinium, thirdly Wilsonidium, fourthly (and now) Castellodinium. Age: Eocene.
Original diagnosis: Cookson and Eisenack, 1961, p.40: Wetzeliella (Rhombodinium) intermedia
Shell flat, usually somewhat longer than broad, rounded rhombic in outline with slightly convex to nearly straight sides and a broadly rounded apex with one or two centrally placed teeth. The lateral horns are represented by slight, broadly-rounded or indented expansions of the outer membrane; a single short pointed horn is developed to one side of the antapex. A circular girdle which crosses the shell in its broadest region is indicated by low ledges or folds especially at the lateral margins or by two rows of short teeth. The margins of the shell are smooth or slightly wavy or toothed, the dorsal and ventral surfaces are either smooth or sparingly dotted, the dots sometimes outlining fields comparable with those of W. lineidentata. The internal body is large, flat, and oval in outlines its wall is thin and in optical section is seen to be composed of small closely arranged rods. A large squarish pylome is situated in the epitheca. Dimensions: Type - length 125 µm, breadth 122 µm, internal body 100 x 100 µm. Range length 111 - 143 µm, breadth 97 - 130 µm.
Affinities:
Cookson and Eisenack, 1961, p.40: Wetzeliella (Rhombodinium) intermedia Wetzeliella intermedia as its name suggests, seems to be a form intermediate between W. lineidentata and W. glabra Cookson. The slightly denticulate margins and surface thickenings, sometimes linearly arranged so as to enclose fields, indicate a certain relationship with W. lineidentata, on the other hand the practically smooth margin and surface of other examples suggests an affinity with W. glabra. W. intermedia agrees with W. rhomboidea Alberti (1961) in certain features, but the latter species has no indication of spines.
Original diagnosis: Cookson and Eisenack, 1961, p.40: Wetzeliella (Rhombodinium) intermedia
Shell flat, usually somewhat longer than broad, rounded rhombic in outline with slightly convex to nearly straight sides and a broadly rounded apex with one or two centrally placed teeth. The lateral horns are represented by slight, broadly-rounded or indented expansions of the outer membrane; a single short pointed horn is developed to one side of the antapex. A circular girdle which crosses the shell in its broadest region is indicated by low ledges or folds especially at the lateral margins or by two rows of short teeth. The margins of the shell are smooth or slightly wavy or toothed, the dorsal and ventral surfaces are either smooth or sparingly dotted, the dots sometimes outlining fields comparable with those of W. lineidentata. The internal body is large, flat, and oval in outlines its wall is thin and in optical section is seen to be composed of small closely arranged rods. A large squarish pylome is situated in the epitheca. Dimensions: Type - length 125 µm, breadth 122 µm, internal body 100 x 100 µm. Range length 111 - 143 µm, breadth 97 - 130 µm.
Affinities:
Cookson and Eisenack, 1961, p.40: Wetzeliella (Rhombodinium) intermedia Wetzeliella intermedia as its name suggests, seems to be a form intermediate between W. lineidentata and W. glabra Cookson. The slightly denticulate margins and surface thickenings, sometimes linearly arranged so as to enclose fields, indicate a certain relationship with W. lineidentata, on the other hand the practically smooth margin and surface of other examples suggests an affinity with W. glabra. W. intermedia agrees with W. rhomboidea Alberti (1961) in certain features, but the latter species has no indication of spines.