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Diconodinium micropunctatum
Diconodinium micropunctatum Backhouse, 1988
Holotype: Backhouse, 1988, pl.26, figs.1a-b
Locus typicus: Perth Basin, W Australia
Stratum typicum: Late Barremian-Early Albian
Original description: Backhouse, 1988, p.84
Cyst small, proximate, subovoid to biconical; epicyst and hypocyst approximately equal in size. Apical horn short (3 Ám) solid and truncate; antapical horn usually a short acicular process offset slightly to the left. Autophragm 0.5 m thick, entirely covered by continuous longitudinal grooves and ridges. Distance between ridges approximately 1 Ám. Grooves lined by rows of closely spaced shallow foveolae, that impart a finely punctate appearance to the autophragm. Paratabulation expressed only by archeopyle and paracingulum. Paracingulum, 4 to 6 Ám wide, indicated bv transverse ridgcs 0.5 Ám high, offset approximately 3 Ám. Parasulus not indicated. Archeopyle intercalary, type la (2a only), standard hexa, seldom clearly observed; operculum free.
Dimensions: Length of holotype 44 Ám, width 37 Ám. Range of length (17 specimens) 34(42)51 Ám, width 25(33)38 Ám.
Affinities:
Backhouse, 1988, p.84: Diconodinium micropunctatum is distinguished from other species of Diconodinium by its small size and finely grooved foveolate surface. Laciniadinium tenuistriatum (Eisenack and Cookson) Morgan 1977 is larger than D. micropunctatum and lacks foveolae.
Holotype: Backhouse, 1988, pl.26, figs.1a-b
Locus typicus: Perth Basin, W Australia
Stratum typicum: Late Barremian-Early Albian
Original description: Backhouse, 1988, p.84
Cyst small, proximate, subovoid to biconical; epicyst and hypocyst approximately equal in size. Apical horn short (3 Ám) solid and truncate; antapical horn usually a short acicular process offset slightly to the left. Autophragm 0.5 m thick, entirely covered by continuous longitudinal grooves and ridges. Distance between ridges approximately 1 Ám. Grooves lined by rows of closely spaced shallow foveolae, that impart a finely punctate appearance to the autophragm. Paratabulation expressed only by archeopyle and paracingulum. Paracingulum, 4 to 6 Ám wide, indicated bv transverse ridgcs 0.5 Ám high, offset approximately 3 Ám. Parasulus not indicated. Archeopyle intercalary, type la (2a only), standard hexa, seldom clearly observed; operculum free.
Dimensions: Length of holotype 44 Ám, width 37 Ám. Range of length (17 specimens) 34(42)51 Ám, width 25(33)38 Ám.
Affinities:
Backhouse, 1988, p.84: Diconodinium micropunctatum is distinguished from other species of Diconodinium by its small size and finely grooved foveolate surface. Laciniadinium tenuistriatum (Eisenack and Cookson) Morgan 1977 is larger than D. micropunctatum and lacks foveolae.