Back
Leptodinium incompositum
Leptodinium incompositum (Drugg, 1970) Lentin and Williams, 1973, p.87
Now Corrudinium. Originally Gonyaulacysta, subsequently Leptodinium, thirdly (and now) Corrudinium.
Holotype: Drugg, 1970, figs.1I-J; Jan du Chêne et al., 1986, pl.17, figs.1-2
Locus typicus: Gulf Coast, USA
Stratum typicum: Oligocene
Original description: Drugg, 1970, p. 810: Gonyaulacysta incomposita
Tract small, ovoidal to spherical in shape. The tabulation (see Fig.1E-H) is 3", 6", 6-7c, 6""", 1 p.pl., 1p., 1"""". The archeopyle is formed by the loss of plate 3". The sulcus contains several small platelets. The cingulum is helicoidal and consists of six to seven cingular plates, some examples seemingly having six plates and some having seven plates. The sutures are in the form of low ridges. The wall is thin and often bears scattered grana. The ornamentation consists of random low ridges, which are often branched, and occasional small tubercles. The ridges usually originate from the sutures and project into the intratabular areas (see Fig 2A). These ornamental ridges mimic sutural ridges and make the determination of the tabulation somewhat difficult. The tract diameter ranges from 25 to 36 Ám, most specimens being about 30 Ám.
Now Corrudinium. Originally Gonyaulacysta, subsequently Leptodinium, thirdly (and now) Corrudinium.
Holotype: Drugg, 1970, figs.1I-J; Jan du Chêne et al., 1986, pl.17, figs.1-2
Locus typicus: Gulf Coast, USA
Stratum typicum: Oligocene
Original description: Drugg, 1970, p. 810: Gonyaulacysta incomposita
Tract small, ovoidal to spherical in shape. The tabulation (see Fig.1E-H) is 3", 6", 6-7c, 6""", 1 p.pl., 1p., 1"""". The archeopyle is formed by the loss of plate 3". The sulcus contains several small platelets. The cingulum is helicoidal and consists of six to seven cingular plates, some examples seemingly having six plates and some having seven plates. The sutures are in the form of low ridges. The wall is thin and often bears scattered grana. The ornamentation consists of random low ridges, which are often branched, and occasional small tubercles. The ridges usually originate from the sutures and project into the intratabular areas (see Fig 2A). These ornamental ridges mimic sutural ridges and make the determination of the tabulation somewhat difficult. The tract diameter ranges from 25 to 36 Ám, most specimens being about 30 Ám.