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Dichadogonyaulax chondra
Dichadogonyaulax chondra (Drugg, 1978) Courtinat, 1989
Originally Ctenidodinium, subsequently Ctenidodinium?, thirdly (and now) Dichadogonyaulax.
Holotype: Drugg 1978, Pl. 1, fig. 10
Locus typicus: Octeville, Normandy, France
Stratum typicum: lower Kimmeridgian, R. uralensis Zone.
Age: Early Kimmeridgian
Original description: Drugg 1978, p 66: Ctenidodinium chondrum
Oblate cyst with a gonyaulacid paratabulation. A low fuzzy apical projection is sometimes present. The wall is thin and finely granulate. Often the grana are arranged so as to form a crude microreticulum with lumina from 1 to 2 Ám across. The parasutures are low bul distinct. The paratabulation of the epicyst is 1 pr, 4" 6". Paraplate 4" lies above paraplate 6" and 1" lies above an anterior sulcal paraplate. Both 1" and 4" are quite elongate and they are juxtaposed. Paraplate 6" is quite small and is juxtaposed to the anterior sulcal paraplate which is about the same size. The paracingulum is about 4 Ám wide and is composed of 6 paraplates. The paratabulation of the hypocyst has not been seen in optimum orientation but is apparently 6"", lp, 1"". The archeopyle is epicystal with the line of separation occuring just anterior to the paracingulum. The cyst height ranges from 55 to 80 Ám and the width from 70 to 95 Ám. Size range based on measurement of 14 specimens.
Types and occurrence: Holotype Pl. 1, fig. 10. Isotypes Pl. 1, figs. 8, 9, 11. All are from Octeville, Normandy, France, lower Kimmeridgian, R. uralensis Zone. Holotype (fig. 10) and Isotype (fig. 11) from base of Argile sableux a" Exogyra virgula dents de Strophodus. Isotype (fig. 8) from middle of Argile gris a"microfaune. Isotype (fig. 9) from middle of Calcaire gris noduleaux
Remarks: Drugg 1978, p 66
This species resembles Ctenidodinium pachydermum (DEFLANDRE) GOCHT, 1970, to the extent that both exhibit low parasutural crests. However the wall of Ct. chondrum is thin whereas that of Ct. pachydermum is thick. Furthermore the shape of Ct. chondrum is oblate as opposed to the more or less spheroidal shape of Ct. pachydermum. All other described species of Ctenidodinium exhibit relatively high and ornate parasutural crests. The species name is from the Greek chondros for grain or granular.
Originally Ctenidodinium, subsequently Ctenidodinium?, thirdly (and now) Dichadogonyaulax.
Holotype: Drugg 1978, Pl. 1, fig. 10
Locus typicus: Octeville, Normandy, France
Stratum typicum: lower Kimmeridgian, R. uralensis Zone.
Age: Early Kimmeridgian
Original description: Drugg 1978, p 66: Ctenidodinium chondrum
Oblate cyst with a gonyaulacid paratabulation. A low fuzzy apical projection is sometimes present. The wall is thin and finely granulate. Often the grana are arranged so as to form a crude microreticulum with lumina from 1 to 2 Ám across. The parasutures are low bul distinct. The paratabulation of the epicyst is 1 pr, 4" 6". Paraplate 4" lies above paraplate 6" and 1" lies above an anterior sulcal paraplate. Both 1" and 4" are quite elongate and they are juxtaposed. Paraplate 6" is quite small and is juxtaposed to the anterior sulcal paraplate which is about the same size. The paracingulum is about 4 Ám wide and is composed of 6 paraplates. The paratabulation of the hypocyst has not been seen in optimum orientation but is apparently 6"", lp, 1"". The archeopyle is epicystal with the line of separation occuring just anterior to the paracingulum. The cyst height ranges from 55 to 80 Ám and the width from 70 to 95 Ám. Size range based on measurement of 14 specimens.
Types and occurrence: Holotype Pl. 1, fig. 10. Isotypes Pl. 1, figs. 8, 9, 11. All are from Octeville, Normandy, France, lower Kimmeridgian, R. uralensis Zone. Holotype (fig. 10) and Isotype (fig. 11) from base of Argile sableux a" Exogyra virgula dents de Strophodus. Isotype (fig. 8) from middle of Argile gris a"microfaune. Isotype (fig. 9) from middle of Calcaire gris noduleaux
Remarks: Drugg 1978, p 66
This species resembles Ctenidodinium pachydermum (DEFLANDRE) GOCHT, 1970, to the extent that both exhibit low parasutural crests. However the wall of Ct. chondrum is thin whereas that of Ct. pachydermum is thick. Furthermore the shape of Ct. chondrum is oblate as opposed to the more or less spheroidal shape of Ct. pachydermum. All other described species of Ctenidodinium exhibit relatively high and ornate parasutural crests. The species name is from the Greek chondros for grain or granular.