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Carnarvonodinium striatigranulatum

Carnarvonodinium striatigranulatum, Parker, 1988

Holotype: Parker, 1988, fig.3G-H
Locus typicus: Carnarvon Basin, W Australia
Stratum typicum: Tithonian

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Original description: [Parker, 1988, p. 170]:

Diagnosis:
Cysts elongate ellipsoidal with slight equatorial bulge, rounded antapex, and short, rounded apical horn.
Autophragm (< 1 µm thick) granulate; most grana considerably less than 1 µm in diameter and height. Grana aligned longitudinally producing weak striate pattern. A small antapical cluster of larger sculptural elements (Fig.3H,D) varying from short truncate processes, < 4 µm high, to low rounded verrucae and grana only slightly larger than those elsewhere on autocyst. Apex also bearing a group of larger grana, verrucae, or coni (Fig. 3K).
Archeopyle apical, type [tA], often with irregular margin, although accessory archeopyle sutures indicate 6 precingular paraplates (Fig.3G). Paratabulation normally indicated only by archeopyle suture; but paracingulum sometimes indicated by weak sculptural alignment.

Dimensions:
Cyst length (excluding sculpture), operculum detached, 45(72)97 µm; cyst width 23(29)37 µm (20 specimens).

Affinities:
Antapical sculptural elements vary from grana to verrucae. However, the weak to strong alignment of grana on the rest of the autocyst is consistent. These features differentiate C. striatigranulatum from C. morganii. Forms with antapical processes also differ from C. morganii in lacking processes on the rest of the body.
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