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Pterodinium cingulatum

Pterodinium cingulatum (O. Wetzel, 1933) Below, 1981

Originally Cymatiosphaera, subsequently Hystrichosphaera, thirdly Spiniferites, fourthly Spiniferites?, fifthly (and now) Pterodinium.
Taxonomic junior synonym: Cymatiosphaera (as Spiniferites?) pterota, according to Below (1981a, p.114) — however, Pavlishina (1990, p.95) retained Cymatiosphaera (now Pterodinium?) pterota.

Holotype: O. Wetzel, 1933, pl.4, fig.10
Locus typicus: Sediment from one of the Baltic states
Stratum typicum: Senonian
Translations Wetzel, 1933 and Below, 1981: LPP

Original description: O. Wetzel, 1933, p. 28: Cymatiosphaera cingulata
Diagnosis: Shell rounded oval to polyhedrical in outline. Small amount of clear, narrow meshes around the mostly dark outline of the inner body. Projected along the short axis, a girdle-shaped gap or elongate field appears, similar to the transverse furrow of the Peridinians. In general, the peridinian habit of this form is most striking; this fossil can be compared especially with my Peridinium illustrans, but also with some spiny shells. Colour dark and light brown.

Additional description: Below, 1981, p. 114: Pterodinium cingulatum ssp. cingulatum
The spheroidal cyst is subdivided into fields by distally smooth, finely dentate, rarely irregularly serrate septa. At gonal positions, the membranes attain a maximum height of about 1/6 of the central body diameter, and in between a slightly smaller, minimum height, as a result of the concave course of the distal edges. In numerous specimens, the septa were seen to split distally in a V-shaped fashion. At their bases, there are pearlstring-like cavities between periphragm and endophragm ("globular" sensu Davey and Williams, 1966). The paratabulation was reconstructed and depicted in text-fig. 75 [from fig.75: 4", 6"", 6c, 6""", 1"""", as, F, r, a, rs, ls, ps. An apical horn is absent or is formed by the septa meeting apically.
Dimensions: Length 50-54 (53) µm, breadth 50-54 (53) µm.

Supplemental description: Hultberg, 1985, p. 142
Proximate cyst, composed of endophragm and periphragm, closely appressed between parasutural septa. The surface of both endophragm and periphragm is smooth. On some specimens, the endophragm and periphragm may be perforated by groups of pores. The shape of the cyst is ellipsoidal, with a short apical horn, formed by fused septa. Paratabulation is clearly expressed by high parasutural septa. At gonal positions, spines of the same height as the septa are present.
The paratabulation is gonyaulacacean, paratabulation formula: 3", 6"", 6c, 1p, 6""",1"""". Paraplate 1" probably represents the fusion of paraplates 1" and 4". Paraplate 6" is distinctly triangular in shape. The archeopyle is precingular, type P, formed by the detachment of paraplate 3"". Operculum free. The operculum is reduced. Paracingulum is indicated by parasutural septa. Parasulcus is indicated by parasutural septa. Size - 32-48 µm (diameter).
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