Pachydendron microthallos Cuif, 1975

Vasseur, Raphaël & Lathuilière, Bernard, 2021, Pliensbachian corals from the Western Tethys, Geodiversitas 43 (22), pp. 1187-1291 : 1284-1286

Pachydendron microthallos Cuif, 1975

( Fig. 67 )

Pachydendron microthallos Cuif, 1975: 169 , txt-figs 5-7, pl. 14: 1, 2. — Melnikova 1986: 88, pl. 20: 3, 4. —Turnšek & Ramovš 1987: 37, pl. 7: 3, 4. — Roniewicz et al. 2007: 590, pl. 4: 1. — Roniewicz 2011: 408 , fig. 2C, D.

TYPE MATERIAL. — Holotype untraced, MNHN. TYPE HORIZON. — Stikinoceras kerri zone, Early Norian, Late Triassic . TYPE LOCALITY. — Alakir Cay (Taurus Mts), Anatolia, Turkey. STUDIED SAMPLE. — CPUN Gu 1105E2-2. GEOGRAPHIC AND STRATIGRAPHIC RANGES. — Triassic of Turkey, Russia, Yugoslavia and Austria, Upper Pliensbachian of Guigou Plateau ( Middle Atlas of Morocco). Until now, the species was considered as a valuable marker of the lower Norian ( Roniewicz 2011).

DESCRIPTION

Phaceloid colony growing by extracalicular lateral budding. Radial elements are thin, compact, free and wavy septa with inner edge often rhopaloid. Septa are organized in three distinct size orders. The first order concerns only one single major septa that is longer and sometimes thicker than the others and define a bilateral symmetry. The third size order consist in very small protosepta. Endotheca made of tabular elements. Wall thick, its nature has not been observed in the Pliensbachian specimen.

Calicular diameter: 1 to 3 mm – Number of septa: 8 to 14.

Figures

FIG. 67. — Pachydendron microthallos Cuif, 1975: A, distal view of the specimen CPUN Gu1105E2-2; B, detail in transverse thin section of two calices of the specimen CPUN Gu1105E2-2;C, longitudinal polished section in the specimen CPUN Gu1105E2-2;D, transverse thin section in the specimen CPUN Gu1105E2-2. Scale bars: A, D, 5 mm; B, 1 mm; C, 4 mm.