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Protobatioladinium lindiense

Protobatioladinium lindiense Schrank, 2005, p.72, pl.10, figs.4–8; text-fig.2.

Holotype: Schrank, 2005, pl.10, fig.4.
Age: Tithonian.

Original description (Schrank, 2005):
Protobatioladinium lindiensis sp. nov. Plate 10, figs. 4–8; Text-Figure 2
Holotype. Slide AZG2, England Finder X55, TUB catalogue number Pn131, Plate 10, fig. 4.
Type locality. Tingutinguti section near Tendaguru, southeast Tanzania.
Type stratum. Trigonia smeei Bed, at sample level Tin9p2.
Repository. Technische Universität Berlin (TUB), Germany.
Derivation of name. From the town of Lindi, a seaport about 60 km southeast of the Tendaguru locality.

Diagnosis. Proximate, acavate, ovoidal dinoflagellate cysts with two small horns. The apical horn is well developed, the antapical horn may be represented by an indistinct bulge or a broad-based protrusion, which is commonly offset towards the ventral side. The cyst wall is thin and densely covered by small or minute granules or bacula. The archeopyle, if present, is of compound type. The operculum is usually in place and consists of an unknown number of apical and intercalary plates.

Description. In lateral view, the cyst shows an ovoid outline (ratio length/width c. 1.35–1.5) with only the antapical horn or with both horns offset towards the ventral side. In dorsoventral orientation the cyst again appears ovoid but slightly wider (length/width c. 1.2– 1.4), the two horns are in an approximately central position and the antapical protrusion is sometimes obscured. The apical horn is cylindrical to conical with a rounded distal part, length c. 5 to 8 µm corresponding to about 8 to 12 % of total cyst length. The antapical horn is a bulge or protrusion of similar length or shorter than the apical horn, but with a much wider base. The archeopyle may be absent or incompletely demarcated by sutures. In dorsoventral orientation it may appear apical. In lateral orientation, a few specimens show rudimentary sutures indicating inclusion of intercalary plates and thus formation of a combination archeopyle. The composition of the operculum cannot be determined directly, but it should consist of three pieces (the apical cap and two intercalary plates as in Protobatioladinium westburiensis NøhrHansen 1986 and Protobatioladinium mercieri FeistBurkhardt and Pross 1998). Tabulation is discernible only adjacent to the archeopyle. The cyst wall is an autophragm with a dense cover of granules and bacula (diameter 0.2–1.2 µm under SEM). These are sometimes fused and form agglomerations of small irregularly shaped ornaments.

Dimensions. Holotype: length 58 µm, width 40 µm. Maximum diameter (length) 53 (59.6) 67 µm, 29 specimens measured.

Discussion. Protobatioladinium lindiensis is different from Protobatioladinium westburiensis Nøhr-Hansen (1986) (early Kimmeridgian, England) and from Protobatioladinium elatmaensis Riding & Ilyina (1996) (Bathonian, Russia) in having a shorter apical horn and a finely granulate to baculate ornamentation. Protobatioladinium mercieri Feist-Burkhardt and Pross (1998) (Bajocian, France) has no antapical horn or projection, and Protobatioladinium lunare Monteil (1992) (Tithonian, France) has a much broader apical horn than Protobatioladinium lindiensis. A specimen of Protobatioladinium lindiensis with a strongly reduced antapical projection (Plate 10, fig. 6) is hardly distinguishable from Pareodiniasp. I Davey (1982) from the Ryazanian of Denmark. Protobatioladinium sp. A Dürr 1988 (early Tithonian, Germany) is closely related to Protobatioladinium lindiensis, and the somewhat coarser granulation of the former may be regarded as of subspecific rank. “Pareodinia ceratophora” sensu Conway (1990) from the Bathonian of Israel may be identical to Protobatioladinium lindiensis.

Present record. Trigonia smeei Bed (base Tin9j2, top Tin9q2).
Previous records. Similar or identical forms occur in the Bathonian of Israel, early Tithonian of Germany and Ryazanian of Denmark (see above).
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