Bounophyllum praecursor ( Frech, 1885 )

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

Bounophyllum praecursor ( Frech, 1885)

Fig. 8H–L .

1885 Clisiophyllum (Dibunophyllum) praecursor sp. nov.; Frech 1885: 47, pl. 17: 3a, b.

1984 “ Dibunophyllum ” praecursor Frech ; Poty 1984: pl. 1: 1.

2002 Dibunophyllum aff. praecursor Frech ; Berkowski 2002: 37, pl. 11: 2.

2005 Bounophyllum pomeranicum sp. nov.; Chwieduk 2005: 418, pl. 12: 4–7, pl. 13: 1–4.

2011 Bounophyllum praecursor Frech ; Denayer et al. 2011: 164, pl. 1: G.

2013 Clisiophyllum cf. omaliusi Haime; Denayer 2013: 36: fig. 1: G.

Type material: Frech’s (1885) types were destroyed during Second World War. No neotype has been designated yet but numerous topotypes are known (e.g., collection PA.ULg, University of Liège , Belgium) .

Type locality: Stolberg , near Aachen, Germany .

Type horizon: Strunian limestone “Zone d’Etroeungt”.

Material.—Five specimens (16 TS, 2 LS), four come from Topluca (Bartın) and one from Gökgöl (Zonguldak), uppermost Famennian.

Diagnosis.—See Berkowski (2002).

Description.—The mean diameter of the corallum is 9.5 mm (maximum 11 mm) and the tabularium is 7 mm wide in average (maximum 9 mm). There are 30 septa of both orders (maximum 32). The major septa are long, straight in the tabularium and confluent with the columella. The minor septa are restricted to the dissepimentarium or enter shortly into the tabularium. The cardinal fossula is poorly developed. The axial structure is dibunophylloid or axophylloid, made of an axial plate with 25–30 twisted radial lamellae attached to the axial ends of the major septa. The largest axial structures are not necessarily developed in largest stages. The dissepimentarium counts no more than 2 rows of concentric interseptal dissepiments, several are thickened. The wall is regular. In longitudinal section, the tabulae are domed in the axial part of the tabularium and depressed in periphery. The dissepiments are steeply inclined toward the tabularium.

Remarks.— Chwieduk (2005) created the species Bounophyllum pomeranicum for specimens with dimensions and number of septa less than those of Frech’s (1885) species. However, these specimens fall in the variability of the topotypes of B. praecursor ( Frech, 1885) . Bounophyllum pomeranicum showing no other distinctive character, it is considered as a junior synonym of B. praecursor . The Turkish specimens fit in the same morphological field of variability, except for their axial structure showing an axial plate much more individualised than in topotypes. This type of variability is, however, commonly observed in taxa with a complex axial structure that may change during the ontogeny or from one specimen to another (e.g., Clisiophyllum , Dibunophyllum , Axophyllum ).

Stratigraphic and geographic range.— Bounophyllum praecursor iscommonintheStrunianstromatoporoidbiostromes and associated facies is Belgium, Germany (Poty 1984), and Poland ( Chwieduk 2005). Its occurrence in Zonguldak and Bartın areas is the first record outside Europe.

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.