Spinofenestella, Termier & Termier, 1971

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 : 558-559

Spinofenestella sp. 2 ( Fig. 6 F-I; Table 13)

MATERIAL EXAMINED. — 7-3-5, 7-3-6, 9-5-1, 9-7, 12-1, 12-2-3, 19-2-1, 23-8, 25-7-1.

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

DESCRIPTION

Micrometric formula: 18-21/11-14//22-25. Reticulated colonies with straight or slightly undulating branches, joined by dissepiments. Bifurcation common. Autozooecia arranged in 2 alternating rows on branches. Apertures circular, spaced 2- 3 per length of a fenestrule, containing 12-13 small nodes and 8 septa in the peristome. Keel low, carrying single row of moderately large and closely spaced nodes. Internal granular skeleton thick, well developed, continuous with obverse keel, nodes, peristome and across dissepiments. Outer lamellar skeleton moderately thick. Microacanthostyles abundant on the obverse surface; scarcely to abundant on reverse side, 10-25 µm in diameter, having distinct hyaline cores and thin laminated sheaths.

INTERIOR DESCRIPTION

Autozooecia triangular in the middle tangential section, low and elongated, with well developed vestibule; aperture positioned at distal to distalabaxial end of chamber. Superior hemisepta short; inferior hemisepta absent.

COMPARISON

The present material is similar to Spinofenestella subspecifica (Shulga-Nesterenko, 1952) from the Lower Permian of the Russian Platform. The latter species has longer fenestrules (0.80-0.90 vs. 0.46- 0.69 mm in Spinofenestella sp. 2).

Genus Alternifenestella Termier & Termier, 1971

TYPE SPECIES. — Fenestella minor Nikiforova, 1933 . Middle Carboniferous, Donetz Basin ( Ukraine).

Figures

FIG. 6. — A-E, Spinofenestella sp. 1; A, B, 17-1-1, tangential section; C, 23-3-1, tangential section showing apertures with apertural nodes; D, 9-5-7, cross section showing the autozooecial chamber with terminal diaphragm (arrow: terminal diaphragm); E, 9-5-10, cross section showing the autozooecial chamber and extensive depositions of outer laminated skeleton; F-I, Spinofenestella sp. 2; F, 9-7, tangential section showing the autozooecial apertures with septa and nodes; G, 9-5-8, tangential section showing the autozooecial apertures and carinal nodes; H, 9-7, tangential section showing the autozooecial apertures with septa and nodes; I, 7-3-5, tangential section; J-L, Alternifenestella sayensis Termier & Termier, 1971; J, 13-4-1, tangential section showing the autozooecial apertures and carinal nodes; K, 5-8-1, tangential section showing the autozooecial apertures and autozooecial chambers; L, 13-4-1, tangential section; M, N, Minilya perelegans (Waagen & Pichl, 1885); M, 25-3-5, tangential section; N, 4-7-3, tangential section; O, P, Fabifenestella jabiensis (Waagen & Pichl, 1885), 25-10-5, tangential section. Scale bars: A, 1 mm; B, I-N, P, 0.5 mm; C, 0.2 mm; D, F, H, 0.1 mm; E, G, O, 0.25 mm.