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Odontochitina operculata

Odontochitina operculata (O.Wetzel, 1933) Deflandre and Cookson, 1955

Originally Ceratium subgenus Euceratium, subsequently (and now) Odontochitina. See also Palaeoceratium (combination not validly published).
Tax. sr. synonym of Odontochitina silicorum Deflandre, 1935, according to Deflandre and Cookson, 1955.
Holotype: Wetzel, 1933, pl.2, fig.21
Paratypes: Wetzel, 1933
Locus typicus: Baltic, NW Europe
Stratum typicum: Senonian
Transaltion Wetzel, 1933: LPP

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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.

Odontochitina operculata (O.Wetzel, 1933a) Deflandre and Cookson, 1955. From Bint (1986, p.138). Large cysts with ceratioid outline and three long, straight, pointed horns, apical, antapical and right lateral. Cornucavate, endocyst subspherical or produced slightly into horn bases. Hypocystal pericoels may be enlarged beyond horn bases. Endophragm smooth; periphragm smooth but occasional perforations, usually 1-3 µm in diameter, may develop along the horns. Archeopyle suture rounded to weakly angular. Rarely, a cingulum is partially indicated by faint transverse lines. Size: overall length average 170, up to 210 µm, width average 44 µm, up to 52, horns 51-102 µm. According to Deflandre (1937), the overall length is 360-420 µm, the endocyst is 54-56 µm.
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Original description: Wetzel 1933, p. 170: Ceratium operculata
Diagnosis: Central body fairly circular. The three long, pointed horns arise from it 120¦ from each other. One (apical horn?) is bent at the end in a whip-like fashion. On some specimens one of the horns with its lower (disc-shaped) part is separated from the central body, resulting in a round aperture at the position of the cap, which carries a horn. Although in one specimen the shell of the central body seems to be torn off rather independently from the hornbase (Text fig. 3). The postion of the girdle-furrow and tabulation is unclear. Colour is dark brown.

Deflandre and Cookson 1955, p. 291-292
The Australian specimens are often folded and deformed, demonstrating the relative sensitivity of these organisms to the treatment to which they have been subjected. However, a few complete specimens have been found in which a globular portion with 2 horn-like appendages and an operculum with a single longer appendage are clearly recognizable.

Supplemental description: Bint, 1986, p. 138
Large cysts with ceratioid outline and three long, straight, pointed horns: apical, antapical, and right lateral. Cornucavate; endocyst subspherical or produced slightly into horn bases, with circular equatorial section. Periphragm separated from endophragm at horns, but hypocystal pericoels may be enlarged beyond horn bases. endophragm smooth; periphragm smooth, but occasional perforations, usually 1-3 µm in diameter, may develop along horns. In these samples, perforations may show a tendency tode concentrated about midway along the horns.
Archaeopyle apical, type (tA), operculum free. Archaeopyle suture rounded to weakly angular; sulcal notch, where discernible, about mid-ventral. Paratabulation not expressed, generally no indication of cingulum or sulcus, but rarely cingulum is partially indicated by faint transverse lines.
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