Primorella rotunda Gorjunova, 1985

Ernst, Andrej, 2016, Bryozoan fauna from the Permian (Artinskian-Kungurian) Zhongba Formation of southwestern Tibet, Palaeontologia Electronica (1946) 51 (9), pp. 1-59 : 34-35

Primorella rotunda Gorjunova, 1985

Figure 15.6-9 ; Table 20

1985 Primorella rotunda Gorjunova , p. 92, pl. 11, figs. 2-3.

2008 Primorella cf. rotunda Gorjunova, 1985 ; Ernst, Weidlich and Schäfer, p. 704, figs. 11.10-11.14.

2013 Primorella rotunda Gorjunova, 1985 ; Ernst and Gorgij, p. 298, figs. 14A-E.

Material. SMF 23.161– SMF 23.164.

Description. Branched colonies, 1.4–1.6 mm in diameter. Autozooecia growing from median axis. Apertures oval. Aktinotostyles abundant, arranged in a single row around apertures. Autozooecial diaphragms and heteromorphs not observed. Walls laminated, 0.010 –0.015 mm thick in endozone, 0.07–0.09 mm thick in exozone.

Remarks. Primorella rotunda Gorjunova, 1985 differs from P. opulenta Gorjunova, 1985 from the Lower Permian (Sakmarian) of Russia, in having thicker branches (branch diameter 1.4–1.6 mm vs. 0.7–0.8 mm in P. opulenta ) and wider autozooecial apertures (aperture width 0.12–0.22 mm vs. 0.11– 0.13 mm in P. opulenta ). Primorella rotunda differs from P. serena Gorjunova, 1975 from the Lower Permian (Sakmarian) of Tajikistan in having thinner colonies (branch diameter 1.4–1.6 mm vs. 2.15– 2.30 mm in P. serena ) and wider autozooecial apertures (aperture width 0.12–0.22 mm vs. 0.12– 0.14 mm in P. serena ).

Occurrence. Lower Permian (Artinskian); Pamir ( Tajikistan). Chili Formation, Lower Permian (Sakmarian–Artinskian); Kalmard area, central Iran. Aseelah Unit, Saal Formation (?Lower Permian); Batain Coast (eastern Oman). Zhongba Formation, Permian (upper Cisuralian–Guadalupian); Zhongba area of southwestern Tibet.

Figures

FIGURE 15. Thin section photographs of Rhabdomeson sp. SMF 23.160 (1–4) and SMF 23.158 (5); and Primorella rotunda Gorjunova, 1985, SMF 23.163 (6) and SMF 23.162 (7–9). 1–3, branch oblique section; 4 and 5, longitudinal section; 6, tangential section; and 7–9, oblique section.