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Protobatioladinium westburiense

Protobatioladinium westburiense Nohr-Hansen, 1986

Holotype: Nohr-Hansen, 1985, pl.3, fig.5; text-fig.7
Age: Early Kimmeridgian
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Holotype: Nohr-Hansen 1986:Pl. 3, fig. 5
Locus typicus. Clay-pit of Blue Circle Portland Cement Company at Westbury, Wiltshire, England.
Stratum typicum: Mutabilis Zone, Lower Kimmeridgian

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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.

Protobatioladinium westburyense Nøhr-Hansen, 1986. See genus. Size: length 67-80 µm, width 34-46 µm, length of apical horn 20-26 µm, holotype length 80 µm, width 46 µm, length of apical horn 23 µm.
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Original diagnosis: Nohr-Hansen 1986, p. 37-38
The species is represented by ovoid proximate cysts with an elongate, slender apical horn abruptly raising from the cyst. A constriction on the apical horn is common. Two antapical horns are indicated by two small rounded bulges. The cysts are often dorso-ventrally flattened, and widest in the paracingular region. The wall is thin and without any internal structure except vesiculae in the apical horn. The surfaces of the cysts are psilate without any ornamentation. The archeopyle sutures reflect a distinct sulcal notch. The archeopyle is compound; type tA2I.

Original description: Nohr-Hansen 1986, p. 37-38
Cyst type. The cyst is proximate with a single wall-layer and no surface ornamentation. Shape. The cyst is ovoid with a prominent apical horn (1/4 to 1/3 of the overall length). The horn is slender, weakly tapering and rises abruptly from the cyst; it is hollow and often has a constriction (fig. 7). Two small rounded bulges occur antapically. These bulges do not exceed 1/15 of the overall length. The cyst is often dorsoventral compressed and folded. Wall relationships. The wall is apparently composed of one layer; the autophragm. The surface is psilate, smooth without any granula. The wall forming the apical horn is about 1 µm thick; it is vesiculate, but otherwise without internal structures. Paratabulation. Paratabulation is only indicated by archeopyle sutures. The apical demarcation of six precingular paraplates is visible. On the basis of their shape these paraplates are interpreted as paraplate 1" to 5" and one anterior sulcal paraplate, probably as. On the dorsal side of the cysts the archeopyle sutures completely demarcate two paraplates. These are located right above the precingular paraplate series, and are interpreted as two anterior intercalary paraplates, respectively la and 2a (fig. 7) Archeopyle. The archeopyle is formed of three opercular pieces. One piece confines the apical paraplate series and two pieces confine an intercallary paraplate each. Although the archeopyle sutures are very distinct (pl. 3, fig. 5), and the operculum should be easily lost, all observed specimens have their operculum in situ. A possible explanation is that the wall is double layered and that the visible archeopyle suture is confined to one of these layers only. The other wall layer is then able to retain the operculum attached in situ.

Dimensions. The total length of the holotype is 80 µm, width is 46 µm. The length of the apical horn is 23 µm. Parameters of 7 complete specimens are: total length 67(74)80 µm, width 34(40)46 µm, length of apical horn 20(22)26 µm.

Occurrence. Present from the top of the Cymodoce Zone to the middle of the Eudoxus Zone.
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Poulsen, 1996, p. 63
Protobatioladinium westburiense Nohr-Hansen 1986
Pl. 3, Figs. 12-14
Remarks. Lentin and Vozzhennikova (1990, p. 93) believed that P. westburiense differs from P. imbatodinense in having an abruptly rising apical horn and a more oval outline, without antapical lobes. Polish specimens of P. imbatodinense have a more abruptly rising horn, but are very similar in shape to one of the figured specimens of P. westburiense by Nohr-Hansen (1986, pl. 3, fig. 6). The apical horn in many species of the Pareodinia complex is variable (see the discussion on Pareodinia robusta in Stevens and Helby, 1987, p. 182). Thus, I do not consider this feature to be particularly diagnostic. However, Polish specimens of P. westburiense, from the same samples in which P. imbatodinense occurs, have a slightly more abruptly rising apical horn. Although Lentin and Vozzhennikova (1990, p. 92) stated that P. westburiense does not have antapical lobes, all specimens of P. westburiense figured by Nohr-Hansen (1986, pl. 3, figs. 5-8) show a clear development of two antapical lobes, as do Danish and Polish specimens.
The key to distinguishing the two species is found in the diagnoses. The surface of P. westburiense is psilate without any ornamentation (Nohr-Hansen, 1986), whereas P. imbatodinense has a surface with granules or flat verrucae (Lentin and Vozzhennikova, 1990). The archeopyle sutures in P. westburiense are slightly more zigzag than those of P. imbatodinense, which often has a straighter archeopyle suture.
Recorded occurrences.
Denmark: Endoscrinium luridum Zone, Perisseiasphaeridium pannosum Subzone - Glossodinium dimorphum Zone, Subzone b.
Poland: Hypselocyclum - Scythicus Zones.
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