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Tuberculodinium rossignoliae

Tuberculodinium rossignoliae Drugg, 1970a, p.116–118, figs.3,10–11. Emendation: Matsuoka and Bujak, 1988, p.87–88.

Holotype: Drugg, 1970, fig.10
Locus typicus: Rumhai, Sumatra
Stratum typicum: Early Miocene

Original description: Drugg, 1970, p. 116-117
Tract discoidal with two wall layers. The endophragm forms the central body of the tract and is about 2 µm thick. The central body bears from 9 to 14 tubular processes with rounded to flaring tips which support an outer thin periphragm. Occasionally some of the processes are dumb-bell shaped. The processes are located peripherally and only rarely are found in a dorsal or ventral position. The archeopyle is seemingly precingular and usually consists of two reflected plates (Figure 3). Rarely there are three plates but in such cases one of the lateral plates commonly is somewhat deformed or only partially visible. Dimensions: Central body 64 µm to 116 µm diameter. Overall diameter 90 µm to 145 µm. "Central" plate of operculum 26 µm to 42 µm high and 13 µm to 32 µm wide at the base.

Emended diagnosis: Matsuoka and Bujak, 1988, p.88
Large to intermediate subspherical to oblate cyst with hollow processes. Cyst wall consisting of two layers which are always separated by processes. Ectophragm very thin and sometimes incomplete between adjacent processes. Processes probably intratabular, spherical to very short, cylindrical. Less than twenty processes present on the precingular and postcingular series, being absent from paracingular, parasulcal, apical and posterior intercalary and antapical reglons. Archeopyle hypocystal, formed by the loss of either two or three posterior intercalary paraplates. Operculum sometimes attached to the hypocyst, but generally datached.
Remarks: The diagnosis is emended to include reference to the hypocystal archeopyle and the number of processes. In the original diagnosis, Drugg (1970) indicated a precingular archeopyle usually consisting of two paraplates. Comparison with Tuberculodinium uancampoae (Rossignol) indicate that both species have a hypocystal archeopyle. Matsuoka (1985) reported the number of opercular plates in modern Tuberculodinium vancampoae as varying from two to five, and suggested that the number of opercular papaplates is not diagnostic for Tuberculodinium species.
Thecal affinity: Probably a species related to the modern genus Pyrophacus. In modern Pyrophacus, two different cysts are known, these being P. steinii (Schiller) and P. holorogium (Stein). Only P. steinii (= Tuberculodinium uancampoae) has processes, whereas P. holorogium does not possess processes. T. rossignoliae may be more closely related to Pyrophacus steinii.

Affinities:
Drugg, 1970, p. 119: This species differs from Tuberculodinium vancampoae and T. wallii in that it usually exhibits two opercular plates rather than three. In addition, the processes tend to be restricted to the peripheral areas rather than uniformly distributed as on T. vancampoae. The present species also lacks the small dorsal and ventral spherical "processes" of T. wallii.
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