Ogbinopora orientalis Gorjunova, 1975

Ernst, Andrej, Senowbari-Daryan, Baba & Hamedani, Ali, 2006, Middle Permian Bryozoa from the Lakaftari area, northeast of Esfahan (central Iran), Geodiversitas 28 (4), pp. 543-590 : 550-552

Ogbinopora orientalis Gorjunova, 1975 ( Fig. 3 A-D; Table 7)

Ogbinopora orientalis Gorjunova, 1975: 67 , pl. 11, fig. 2a, b.

HOLOTYPE. — No. 2351/478, PIN; Central Pamir ; Upper Permian.

MATERIAL EXAMINED. — 2-1, 4-4, 4-12, 5-5, 5-6-(1- 3), 5-7, 5-9, 5-10, 19-4, 21-2, 23-8, 24-1, 24-2, 24-5, 25-6.

OCCURRENCE. — Central Pamir, Upper Permian. Lakaftari: central Iran, Jamal Formation, Middle Permian.

DESCRIPTION

Ramose colonies with a bundle of axial zooecia in the endozone. Branches 2.20-3.67 mm in diameter, with well defined 0.55-1.11 mm wide exozones. Axial bundle in the endozone consisting of 11 to 14 rows of zooecia, having diameters of 0.78-1.56 mm. Axial zooecia polygonal in cross section. Autozooecia long, budding along to the axial bundle, in the exozone bending outwards and intersecting the surface at angles of 90°. The angle between the back wall of the autozooecia and the axial bundle reaches 24-28° (25.67° averagely). Autozooecial apertures oval, arranged in regular rows, spaced 4-5 in 2 mm along branches, and 6.0-7.5 in 2 mm diagonally. Metazooecia circular and oval, 5-8 arranged between the apertures. Basal diaphragms rarely occur. Both superior and inferior hemisepta present, well developed, positioned in the distal part of autozooecia. Extensive secondary overgrowth occurring.

COMPARISON

This bryozoan is common in the Jamal Formation. It is similar to Ogbinopora orientalis described on three specimens from the Upper Permian of Central Pamir. Gorjunova (1975) mentioned that neither diaphragms nor hemisepta in this species occur. However, she pictured two oblique sections, in which some short inferior hemisepta can be observed ( Gorjunova 1975: pl. 11, fig. 2a, b). Ogbinopora orientalis differs from O. armeniensis Shishova, 1965 by thinner colonies (2.00-3.67 vs. 3.50-5.50 mm in O. armeniensis ), smaller apertures (0.07-0.13 vs. 0.10-0.15 mm in O. armeniensis ), and in character of hemisepta. O. armeniensis possesses only a single superior hemisepta positioned in the part of the autozooecium transitional between endozone and exozone.

Figures

FIG. 3. — A-D, Ogbinopora orientalis Gorjunova, 1975; A, B, 5-6-3, longitudinal section (arrow in B: hemisepta); C, 5-9-3, cross section; D, 5-6, tangential section; E-I, Ascopora gracilis n. sp.; E, paratype 23-6-7, longitudinal section; F, 23-6-5, tangential section; G, 23-6-8, cross section; H, 23-6-7, longitudinal section; I, holotype SMF 2112, oblique tangential section (arrow: acanthostyle); J- M, Fistuliporidae indet. (?Eridopora); J, 4-8-11, tangential section; K, 19-4-10, longitudinal section showing hemisepta; L, 19-4-10, longitudinal section showing wall structure; M, 19-4-10, tangential section showing lunarium; N-P, Eridopora oculata Bassler, 1929; N, 11-1, tangential section; O, 16-1-7, tangential section showing hexagons around apertures; P, 16-1-7, longitudinal section. Scale bars: A, 1 mm; B, D, G, H, J, N-P, 0.5 mm; C, 2 mm; E, K, M, 0.1 mm; F, I, 0.25 mm; L, 0.05 mm.