Dinogymnium lanceolatum May, 1977

Now Yolkinigymnium. Originally Dinogymnzum, subsequently (and now) Yolkinigymnium.
Holotype: May, 1977, pl.2, figs.9-10; Lentin and Vozzhennikova, 1990, Appendix A, fig.41
Age: Late Campanian-Early Maastrichtian

(May, 1977)
Type locality: Atlantic Highlands, New Jersy.
Type stratum: Mount Laurel Sand.
Description: Delicate, elongate test, ca. 8-12 times longer than wide; appears single layered. Epitract lanceolate, tapering to a pointl length is 1/4 to 1/5 of total cyst, separated from hypotract by shallow, weakly-defined, levorotatory cingulum having offset ca. 1/2 cingulum width. Epitract nearly as broad as hypotract across cingulum. Hypotract tapers to a rounded antapex. No archeopyle abserved. Surface finely scabrate.
Discussion: Dinogymnium lanceolatum compares with certain modern Gymnodinium speices in the same manner as reprted for D. elongatum. The long delicate hypotract tends to fold and collapse. Four specimen of good quality, and six of poor quality were found. From the four good specimens a mean cingulum index of 24 was etermined.
Affinity: Same as D. elongatum
Dimensions: Holotype 140 µm x 13 µm. Observed range (four specimens measured): length 140-165 µm, width 13-20 µm. Cyst wall ca. 0.5 µm thick. Cingulum index range 21-26.
Occurrence: Mount Laurel Sand, extremely rare. Navesink Formation, extremely rare. Greatest occurrence, sample no. 207. Occurred in five samples.