Retiophyllia vesicularis, Roniewicz, 2011

Roniewicz, Ewa, 2011, Early Norian (Triassic) corals from the Northern Calcareous Alps, Austria, and the intra-Norian faunal turnover, Acta Palaeontologica Polonica 56 (2), pp. 401-428 : 414-415

Retiophyllia vesicularis sp. nov.

Fig. 4E .

Etymology: From Latin vesicularis , vesicular; in reference to the structure of the endotheca.

Type material: Holotype: GBA 2009 /019/12, with thin sections; paratype: GBA2009 /019/13.1.

Type locality: Austria, Northern Calcareous Alps , southern Dachstein Plateau, site ca. 50 m north−west of Feisterscharte .

Type horizon: Norian, Lacian 1, Epigondolella quadrata Conodont Zone , light grey organodetritic limestone.

Diagnosis.—Maximum diameter of ca. 5–7 mm; axial cavity empty and wide. Septal apparatus of unstable symmetry, chiefly sixfold. Septa of three size orders, short; the S1 septa very thick. Dissepiments large, vesicular.

Comparison.—From other species it differs in large, convex dissepiments and S1 septa dominating in size over the remaining ones. The external wall surface shows longitudinal furrows associated with the S1 septa, a feature not encountered in other species of the genus.

Material.— The holotype (see above) with thin sections, and GBA 2009 /019/13.

Measurements (in mm): GBA d s ed/5 Remarks 5– 7 adult stage 2009/019/12 24 (6S1+6S2+12S3) 7–8 3.5 early stage

Description.—Adult corallites circular in section, with exsert S1 septa. A tendency to petaloid shape of corallite in transverse section is observed, with furrows in the position of the S1 septa. Free axial space wide. Septal apparatus composed of very few septa arranged into six (rarely five) regular systems,. The S1 septa, ending at some distance from the axis, are very thick, fusiform, with large, irregular lateral granules. The S2 septa are about half the radius in length, the S3 septa subequal in thickness to the S2 septa, attaining one−fourth the radius. Adaxial septal parts thin, zigzag. Endotheca composed of large, equal vesiculae which are arranged in a single peripheral circle and an axial series traversing the lumen. Axial dissepiments are convex. Wall thick.?Colony increase by the equivalent division of corallites.

Microstructure.—A straight row of small−trabecular centres may be discerned in the midline.

Stratigraphic and geographic range.— Austria: Northern Calcareous Alps, Dachstein Plateau, north and south of Feisterscharte, lower Norian, Epigondolella quadrata Conodont Zone.

Figures

Fig. 4. Reimaniphylliid corals from vicinity of Feisterscharte, Austria, early Norian, Triassic. A. Retiophyllia sp.; GBA 2009/019/4g. Septal apparatus with + thick S1 septa, transverse section. B. Retiophyllia aranea sp. nov.; GBA 2009/019/14. corallites circular in section (B1) with a large axial space (B2); longitudinal/oblique section (B3) showing sub−horizontal, large dissepiments in the axial space, and longitudinal section of distal part of the corallite (B4) show− ing convex dissepiments at the periphery.C. Retiophyllia aff. fenestrata (Reuss, 1854); GBA 2009/019/11a, b. Corallites in transverse (C1) and longitudinal (C2) sections showing small number of septa and large dissepiments. D. Retiophyllia aff. tolminensis Turnšek, 1987; GBA 2007/152/3f. Corallite in transverse section showing zigzag septa. E. Retiophyllia vesicularis sp. nov.; GBA 2009/019/12g, c. Corallites in longitudinal (E1) and transverse (E2) sections; note large and convex dissepiments and irregular shape of septa. F–G. Craspedophyllia? sp. F. GBA 2009/019/16b; transverse sections with corallites showing rare, obliquely directed menianes. G. Zigzag traces of septal microstructure; GBA 2009/019/17a (G1), GBA 2009/019/17b (G2).