Minilya perelegans ( Waagen & Pichl, 1885 )

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 : 559-560

Minilya perelegans ( Waagen & Pichl, 1885) ( Fig. 6M, N ; Table 15)

Fenestella perelegans Waagen & Pichl, 1885: 777 , 778, pl. 87, figs 1-3. — Fantini Sestini 1965: 28, 29, pl. 2, fig. 1. — Yang et al. 1981: 89, pl. 2, fig. 7.

Non Meek, 1872: 153, pl. 7, fig. 3-3d.

Minilya perelegans – Crockford 1944a: 173.

MATERIAL EXAMINED. — 4-1, 4-5-2, 4-6-3, 4-8, 5-1-1, 5-6-3, 5-8-5, 12-1, 16-1, 19-4, 24-1-2, 25-3-5, 25-7.

OCCURRENCE. — Salt Range: Pakistan, Middle Permian (Guadalupian) ( Waagen & Pichl 1885). Xizang: Tibet, China, Lower Permian. Lakaftari: central Iran, Jamal Formation, Middle Permian.

DESCRIPTION

Micrometric formula: 21-26/17-21//17-21. Reticulated colonies with straight branches, joined by thin dissepiments. Bifurcation common. Autozooecia arranged in 2 alternating rows on branches. Apertures circular having high peristomes with small nodes, spaced 1-2 per length of a fenestrule. Shape of fenestrules varying from oval to rectangular with rounded corners. Keel low, carrying two alternating rows of small closely spaced nodes. Internal granular skeleton thin, continuous with obverse keel, nodes, peristome and across dissepiments. Outer lamellar skeleton thin. Abundant microacanthostyles on the reverse surface, having distinct hyaline cores and dark laminated sheaths, 10-25 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

Minilya perelegans is similar to M. paratuberculifera ( Yang & Lu, 1962) from the Upper Permian of China and Khabarovsk region ( Russia) ( Morozova 1970a), differing from it in having thicker branches (0.24-0.35 vs. 0.22-0.24 mm in M. paratuberculifera ). Another similar species is M. shurae (Morozova, 1970) from the Middle Permian (Kazanian) of the Russian Platform, which differs from M. perelegans in having smaller fenestrules.

REMARK

Waagen & Pichl (1885) referred this bryozoan to the species Fenestella perelegans Meek, 1872 ( Meek 1872: 153, pl. 7, fig. 3-3d) from the Upper Carboniferous of Nebraska (see also Fantini Sestini 1965: 28, 29, who placed it into Fenestrellina ). Crockford (1944a: 173) included the species Fenestella perelegans Waagen & Pichl, 1885 (not Meek, 1872) in her new genus Minilya . She recognized that these are different species (and genera), with the occurrence in the Upper Carboniferous of Nebraska ( Meek 1872) and in the Middle Permian of Salt Range ( Waagen & Pichl 1885). We support this conclusion and use the name “ Minilya perelegans ” for the species established by Waagen & Pichl (1885). The species of Meek (1872) should keep its specific name but change the generic assignment.

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.