Caninophyllum charli, Denayer, 2016

Denayer, Julien, 2016, Rugose corals across the Devonian-Carboniferous boundary in NW Turkey, Acta Palaeontologica Polonica 61 (1), pp. 51-70 : 63-64

Caninophyllum charli sp. nov.

Fig. 8A–E .

Etymology: In honour of François Charles, who first described corals in the Carboniferous of Zonguldak.

Holotype: Corallum included in a rock matrix, specimen G.8.1.1 , Zonguldak 2011 (5 TS).

Type locality: Gökgöl section, south of Zonguldak, NW Turkey.

Type horizon: Yılanlı Formation, unit G8, lower Tournaisian (Hastarian, MFZ3 biozone of Poty et al. 2006).

Material.— Eighteen specimens (27 TS, 2 LS): 15, including the holotype, coming from Gökgöl (Zonguldak) and 3 from Dallıca (Bartın), lower Tournaisian .

Diagnosis.—Small Caninophyllum , 30–32 mm in diameter (15–20 mm for the tabularium), having 42–46 septa of each order. Major septa extending to the axis in the juvenile stages but withdrawn in the mature stages, thickened in the cardinal parts of the tabularium. Minor septa rudimentary. Dissepimentarium narrow but complex, constituted of concentric, herringbone and arched interseptal dissepiments. Cardinal fossula conspicuous and opened.

Description.—The corallum is cylindrical, 3–5 cm high. The mean diameter is 32 mm (maximum 38 mm) and the tabularium is in average 17 mm wide (maximum 21 mm). There are, on average, 46 septa of each order (maximum 48). The major septa are long, reaching the axis in the juvenile stages but withdraw toward the periphery during the growth, leaving a central zone of 5–6 mm-wide in the centre of the tabularium ( Fig. 8A 2 , C, D). They are thickened but their axial ends are sharp. They bend toward the cardinal fossula in the cardinal quadrants but are straighter in the counter quadrants. The initial thickening occurring in the whole tabularium rapidly decreases during the growth but maintains in the cardinal quadrants in the mature stages. The cardinal septum is shorter and thicker than its neighbouring septa. The minor septa are rudimentary or restricted to the peripheral part of the dissepimentarium. The cardinal fossula is well marked. The dissepimentarium counts 5–12 rows of concentric and herringbone dissepiments and several arched dissepiments in the peripheral part. Second order lonsdaleoid dissepiments occur in some specimens. The inner row of dissepiments is thickened in continuity with the septa ( Fig. 8A 3 ). The wall is thin, regular or slightly undulating. In longitudinal section, the tabulae are incomplete, horizontal or domed in the axial part of the tabularium, domed or mesa-shaped in the peripheral part ( Fig. 8E ). A peripheral gutter develops in the mature stages. The dissepiments are 1.5– 3 mm long, 1 mm high and steeply declined toward the tabularium.

Remarks.—The small size and number of septa are diagnostic of Caninophyllum charli sp. nov. and allow its discrimination from C. archiaci (Milne-Edwards and Haime, 1852) and C. tomiense ( Tolmachev, 1931) . The new species shares its dimensions with C. patulum (Michelin, 1846) but the latter show a larger dissepimentarium usually composed only of concentric and herringbone dissepiments. The septa are less thickened and more withdrawn toward the periphery in C. patulum while its cardinal septum is longer in the juvenile stage. The tabularium is also different: the tabulae are flat or slightly domed in the central part in C. charli but are clearly domed in C. patulum . Poty and Xu (1996) figured two species of small Caninophyllum from the lower Tournaisian Uralinia tangpakouensis Zone of S China. C. cystosum Jiang, 1982 has 41–46 septa for a diameter of 25– 35 mm but differs from C. charli by an inconspicuous cardinal fossula and a long counter septum often connected to the cardinal septum. C. shaoyangense Jiang, 1982 is smaller 17 mm and 38 septa of both orders) and has a very large dissepimentarium and septa almost not thickened in the tabularium.

Stratigraphic and geographic range.— Caninophyllum charli sp. nov. was collected in a bioclastic level dated of the lower Tournaisian (Hastarian) by foraminifers (MFZ3 biozone) in the Gökgöl (Zonguldak). Crushed specimens were collected in equivalent levels in the Dallıca (Bartın)

Figures

Fig. 8. Devonian–Carboniferous rugose corals from Turkey. A–E. Caninophyllum charli sp. nov. from the lower Tournaisian (upper Hastarian) of Zonguldak, Gökgöl section. A. Holotype, G.8.1.1, successive TS (A1, A2); close-up view of the dissepimentarium, TS (A3). B. G.8.6.1, successive TS (B1, B2). C. G.8.4.3, TS. D. G.8.4.2, TS. E. G.8.3.2, LS. F, G. Uralinia simplex (Yü, 1933) from the lower Tournaisian (lower Hastarian) of Bartın, Topluca section. F. ET.9c.7, TS. G. ET.9c.8, TS. H. Amplexocarinia rozkowskae (Fedorowski, 2003) from the uppermost Famennian (Strunian) of Bartın, Dallıca section, D.2.4.II’, TS. I.?Metriophyllum sp. from the uppermost Famennian (Strunian) of Bartın, Topluca section, ET.11.X, TS. J–L. Bounophyllum praecursor (Frech, 1895) form the uppermost Famennian (Strunian) of Bartın, Topluca section. J. ET.12a.1.III, successive TS (J1–J3). K. ET.12a.1.II, TS. L. ET.12a.1.V, LS. Scale bar A–G, 5 mm; H, 3 mm; I, 1.9 mm; J–L, 2.5 mm.

Fig. 2. Simplified lithological columns of the main sampled sections with the stratigraphic range of the rugose corals in the Yılanlı Formation and the position of samples with foraminifers (DFZ7, MFZ1, MFZ2, MFZ3 referring to the biostratigraphic zones of Poty et al. 2006). The position of the D–C boundary, based on foraminiferal assemblage, is indicated by the double arrow.

Fig. 3. Uppermost Famennian (Strunian) facies in the Topluca section, Turkey. A. Lower stromatoporoid biostrome (unit ET12a in Fig. 2). B. Bioclastic facies of the unit ET11 crowded with large campophyllid solitary rugose corals in a packstone matrix.