Gongylodinium serratum Head et al., 1989

Now Bitectatodinium?. Originally Gongylodinium, subsequently (and now) Bitectatodinium?.
Holotype: Head et al., 1989, pl.3, fig.14-16
Locus typicus: ODP leg 105, site 646, Labrador Sea
Stratum typicum: Late Miocene

Original diagnosis: Head et al., 1989, p.457
Cyst proximate, autophragmal, and spherical. Surface nearly smooth or faintly granulate to faintly granulorugulose. Archeopyle precingular Type 2P, operculum free, probably compound. Principal archeopyle suture, angular and with finely serrated margins. There is no other expression of paratabulation.
Dimensions. Holotype: maximum diameter, 40 µm. Range in maximum diameter, 34(42.5)49 µm (based on relatively uncompressed cysts). Wall thickness, up to 1.2 µm. Thirteen specimens were measured.

Original description: Head et al., 1989, p.457
Uncompressed cysts are spherical but may be folded into a broadly eliptical outline. The principal archeopyle suture is angular and has distinctively serrated archeopyle margins. The adapical margin of the archeopyle may be irregular, particularly in thinner walled (i.e., 0.5 µm or less) specimens. Accessory sutures were not identified with certainty. The operculum is free and compound (indicated by separated opercular pieces, observed within two cysts). Observed opercular pieces have serrated margins. We were unable to determine specific precingular paraplates involved in archeopyle formation because of the somewhat irregular adapical archeopyle margin.

Affinities:
Head et al., 1989, p.457: The serrated archeopyle margin of this species distinguished it from all other species of Gongylodinium.