Alternifenestella sayensis 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 : 559

Alternifenestella sayensis Termier & Termier, 1971 ( Fig. 6 J-L; Table 14)

Alternifenestella sayensis Termier & Termier, 1971: 42 , pl. 29, fig. 7.

MATERIAL EXAMINED. — 4-2, 4-15-9, 5-8-1, 13-4-1.

OCCURRENCE. — Afghanistan, Middle Permian (Murgabian). Lakaftari: central Iran, Jamal Formation, Middle Permian.

DESCRIPTION

Micrometric formula: 20-25/13-18//22-23. Reticulated colonies with straight branches, joined by dissepiments. Bifurcation common. Autozooecia arranged in 2 alternating rows on branches, having circular apertures with smooth peristomes, spaced 2-3 per length of a fenestrule. Shape of fenestrules varying from oval to rectangular with rounded corners. Keel low, carrying singular row of small nodes. Internal granular skeleton thin, continuous with obverse keel, nodes, peristome and across dissepiments. Outer lamellar skeleton thin. Abundant microacanthostyles occurring on the reverse colony surface, 10-15 µm in diameter.

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

Alternifenestella sayensis is similar to A. subconstans ( Yang & Lu, 1962) from the Upper Permian of China and Guadalupian Gnishik Horizon of Transcaucasia ( Morozova 1970a), but differs from the latter in having thicker branches (0.26-0.35 vs. 0.20-0.22 mm in A. subconstans ), as well as smaller fenestrules.

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.