Back
Deflandrea delineata
Deflandrea delineata Cookson and Eisenack, 1965c, p.140-141, pl.18, figs.3-5; text-fig.1.
Holotype: Cookson and Eisenack, 1965c, pl.18, figs.4-5; text-fig.1. Taxonomic junior synonym (at specific rank): Ceratium fusus forma nodosum (subsequently Palaeocystodinium? rhomboides subsp. nodosum), according to Sarjeant (1985b, p.157). Age: Paleocene.
Original description: Cookson and Eisenack, 1965, p.140
Shell rather flat, roughly five-sided in outline, longer than broad. Epitheca somewhat longer than the hypotheca with a prominent, broadly-based, tapering apical horn. The short antapical horns, which are equal in size, are broadly-based, sharply-pointed, widely separated and strongly divergent. Girdle circular, indicated laterally by shallow concavities on both sides of the shell, rather narrow and delimited by low ledges which, on the ventral surface, curve downwards to pass over the boundaries of the longitudinal furrow in which the thickening associated with the flagella-pore is evident (Pl. 18, fig. 3). Wall of shell thick, slightly tabulated, its surface variously striated as the result of the longitudinal arrangement of the small dot-like to elongate surface thickenings (Pl. 18, iig. 3). The degree of clearness and extent of the tabulation varies considerably in individual specimens. It has been best seen in the holotype (Pl. 18, fig. 4, 5; Fig. 1 ) . On the dorsal surface of this specimen 3 plates, numbered as in Peridinium 3"" 4"" 5"", are situated between the girdle and archeopyle; no clear tabulation is evident on the hypotheca but a small plate 2""" seems to be outlined on the lefthand side, and a corresponding one 4""" on the right-hand side of plate 3""". On the ventral surface of the epitheca two small plates (Fig. 1a, b) and a large, broad and elongate one p", situated immediately above them, are clearly outlined. Capsule circular or ellipsoidal in outline with the long axis perpendicular to the long axis of the shell; its wall varies in thickness in individual specimens. The archeopyle is broader than long and seems to correspond with plate 2a.
Dimensions: Holotype--overall length 171 Ám; overall width 105 Ám; capsule 86x95 Ám. Range--overall length 159-190 Ám; overall width 116-130 Ám; capsule 69-84x85-92 Ám.
Affinities:
Cookson and Eisenack, 1965, p.141: Of the previously described species of the genus Deflandrea, the one to which D. delineata seems to be most closely related is D. speciosa Alberti (1959) from an Upper Paleocene deposit in N. Germany. However, the presence of a ¦ distinct form of tabulation, the stronger development of the girdle, the characteristic arrangement of the ornament of the shell wall, as well as the lack of the denticulate ledges mentioned by Alberti as present in the German species, seem sufficient justification for the separation herein proposed.
Holotype: Cookson and Eisenack, 1965c, pl.18, figs.4-5; text-fig.1. Taxonomic junior synonym (at specific rank): Ceratium fusus forma nodosum (subsequently Palaeocystodinium? rhomboides subsp. nodosum), according to Sarjeant (1985b, p.157). Age: Paleocene.
Original description: Cookson and Eisenack, 1965, p.140
Shell rather flat, roughly five-sided in outline, longer than broad. Epitheca somewhat longer than the hypotheca with a prominent, broadly-based, tapering apical horn. The short antapical horns, which are equal in size, are broadly-based, sharply-pointed, widely separated and strongly divergent. Girdle circular, indicated laterally by shallow concavities on both sides of the shell, rather narrow and delimited by low ledges which, on the ventral surface, curve downwards to pass over the boundaries of the longitudinal furrow in which the thickening associated with the flagella-pore is evident (Pl. 18, fig. 3). Wall of shell thick, slightly tabulated, its surface variously striated as the result of the longitudinal arrangement of the small dot-like to elongate surface thickenings (Pl. 18, iig. 3). The degree of clearness and extent of the tabulation varies considerably in individual specimens. It has been best seen in the holotype (Pl. 18, fig. 4, 5; Fig. 1 ) . On the dorsal surface of this specimen 3 plates, numbered as in Peridinium 3"" 4"" 5"", are situated between the girdle and archeopyle; no clear tabulation is evident on the hypotheca but a small plate 2""" seems to be outlined on the lefthand side, and a corresponding one 4""" on the right-hand side of plate 3""". On the ventral surface of the epitheca two small plates (Fig. 1a, b) and a large, broad and elongate one p", situated immediately above them, are clearly outlined. Capsule circular or ellipsoidal in outline with the long axis perpendicular to the long axis of the shell; its wall varies in thickness in individual specimens. The archeopyle is broader than long and seems to correspond with plate 2a.
Dimensions: Holotype--overall length 171 Ám; overall width 105 Ám; capsule 86x95 Ám. Range--overall length 159-190 Ám; overall width 116-130 Ám; capsule 69-84x85-92 Ám.
Affinities:
Cookson and Eisenack, 1965, p.141: Of the previously described species of the genus Deflandrea, the one to which D. delineata seems to be most closely related is D. speciosa Alberti (1959) from an Upper Paleocene deposit in N. Germany. However, the presence of a ¦ distinct form of tabulation, the stronger development of the girdle, the characteristic arrangement of the ornament of the shell wall, as well as the lack of the denticulate ledges mentioned by Alberti as present in the German species, seem sufficient justification for the separation herein proposed.