Radiolites nouleti Bayle, 1857

Săsăran, Liana, Săsăran, Emanoil & Bucur, Ioan I., 2018, Upper Cretaceous Rudist-Bearing Mixed Siliciclastic-Carbonate And - Volcanoclastic Deposits From Strâmturii Valley, Borod Basin, Northern Apuseni Mountains: Description, Microfacies And Depositional Environments, Acta Palaeontologica Romaniae 14 (1), pp. 3-20 : 12

Radiolites nouleti Bayle, 1857

Fig. 7 h-i.

1908 Radiolites nouleti Bayle- Toucas, p. 72, pl.13, figs.18-19.

1967 Radiolites nouleti Bayle- Polšak, pp. 69, 180, pl.44, fig.4,4a, pl.45, figs.2-5

1967 Radiolites nouleti Bayle- Lupu and Lupu, p. 308.

1982 Radiolites nouleti Bayle- Czabalay, p. 50, 85; pl.39, fig.11, pl.40, figs.3-4,7.

Material: One RV specimen (BBU-MPS-24083).

Description. Right valve conical, thick-shelled, having more than 50 mm length and 78 mm diameter antero-posterior and 55 mm dorsoventral ( Fig. 7h ). The ornamentation consists in fine and rounded longitudinal ribs, 2 mm in thickness in the dorsal side. On the ventral side, dense, regularly folded growth lamellae can be seen, slightly ondulated in interband. The interband (Ib) is very wide, centrally depressed separating the radial bands Vb and Pb which are simple folds with almost the same amplitude ( Fig. 7h ). In transversal section, the ligamental ridge (L) is triangular at base, with 11 mm in length and its inner margin truncated. Anterior and posterior of the ligamental ridge are two small, oval cavities ( Fig. 7i ). The outer shell layer varies between 13 to 15 mm in thickness, having only 5 mm in ventral side in interband area. Cells of the outer shell layer are irregular polygonal, predominantly penta- and hexagonal ( Fig. 7i ).

Remarks: Radiolites nouleti is a large radiolitid easy identifiable by its thick-shelled, large interband and dense folded growth lamellae.

Age and distribution: Santonian-early Campanian in Croatia ( Polšak et al., 1982), Romania ( Lupu, 1976); early Campanian in France ( Bilotte, 1985), Hungary ( Czabalay, 1982), Serbia ( Milovanovic, 1935) and Spain ( Vicens, 1992); late Maastrichtian in Spain ( Bilotte, 1985).

Figures

Fig. 7 a, b Bournonia excavata d'Orbigny, 1847, (inventory no. 24078 BBU-MPS =no.1246 sample field); a transverse section through RV close to the commissure, showing the myocardinal elements: anterior and posterior tooth and myophores (am, pm) of the opposite valve; b view of flat posteroventral side of RV; c Gorjanovicia endrissi (Böhm)(24079 BBU-MPS) – transverse section of RV showing compact layer, concave ventral band (Vb); Ib- narrow and wide Pb with 3 fine rounded costae; d, e Praeradiolites subtoucasi (Toucas): d transverse section through RV (24080-BBU-MPS), unknown commissure. The outer shell layer from ventral side is eroded thus the radial bands are missing. e transverse section on other specimen (24081-BBU- MPS) having outer shell layer partially broken but preserve the myocardinal apparatus. f, g Radiolites squamosus (d'Orbigny): f specimen with both valves showing convex LV, very eroded and the ornamentations of RV consist in dense growth lamellae (sample no. 24082 BBU-MPS); g ventral side of RV of the same specimen showing radial bands (Vb and Pb) with folds upward to commissure and the narrow interband (Ib). h-i Radiolites nouleti (Bayle)(sample no. 24083 BBU-MPS): h large conical RV, thick-shelled, with dense folded growth lamellae, slightly ondulated in large interband (Ib); i transverse section in RVof the same specimen, showing thick cellular outer shell layer, ligamental ridge and accessory cavities. j, k Sphaerulites boreaui (Toucas)(sample no. 24084 BBU-MPS), j specimen with both valves, top view, showing LV, thin and smaller than lower valve and large RV with expanded, sub-horizontal growth lamellae; k transverse section through RV, showing thickness of cellular