Campophyllum flexuosum ( Goldfuss, 1826 )

Denayer, Julien, 2016, Rugose corals across the Devonian-Carboniferous boundary in NW Turkey, Acta Palaeontologica Polonica 61 (1), pp. 51-70 : 56-58

Campophyllum flexuosum ( Goldfuss, 1826)

Fig. 5A–M .

1826 Cyathophyllum flexuosum sp. nov.; Goldfuss 1826: 47, pl. 17: 3a, b.

1850 Campophyllum flexuosum (Goldfuss) ; Milne-Edwards and Haime 1850: pl. 68.

1885 Cyathophyllum aquisgranensis sp. nov.; Frech 1885: 40, pl. 9: 1C.

1885 Cyathophyllum lindströmi sp. nov.; Frech 1885: 38.

1913 Caninia dorlodoti sp. nov.; Salée 1913: 44: figs. 1, 2, pl. B: 2.

1917 Cyathophyllum aquisgranensis Frech ; Vaughan 1917: 38, pl. 18: 3, 4.

1929 Cyathophyllum aquisgranensis Frech ; Dehée 1929: 46, pl. 14: 4a, b.

1932 Caninia flexuosa (Goldfus) ; Schindewolf 1932: 476, fig. 3.

1935 Caninia dorlodoti Salée ; Gorsky 1935: 104, pl. 8: 2, 3.

1961 Palaeosmilia aquisgranensis (Frech) ; Conil 1961: 348, pl. 18: 3, 4.

1965 Campophyllum flexuosum (Goldfuss) ; Hill and Jull 1965: 206, pl. 7.

1984 Campophyllum flexuosum (Goldfuss) ; Poty 1984: pl. 2: 1–3.

2005 Campophyllum flexuosum (Goldfuss) ; Chwieduk 2005: 411, pl. 1: 8, pl. 7: 1–3.

2010 Campophyllum flexuosum (Goldfuss) ; Poty 2010: 395, fig. 5.

2011 Campophyllum flexuosum (Goldfuss) ; Denayer et al. 2011: 160, pl. 1: B.

2013 Campophyllum sp. 2 ; Denayer 2013: 36, fig. 1E.

Lectotype: Specimen Goldfuss/197a , collection Goldfuss, Geology and Palaeontology Museum, Bonn, Germany, designated by Hill and Jull (1965).

Type locality: Stoberg, near Aachen, Germany.

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

Material.— Thirty-six specimens and numerous fragments (65 TS, 20 LS); 24 from the Topluca (Bartın) , 7 from Esenpınar (Bartın) , and 5 from Gökgöl (Zonguldak), uppermost Famennian .

Diagnosis. —See Hill and Jull (1965).

Description.—The corallum is solitary and cylindrical, up to 15 cm high with a maximum diameter of 25 mm in the calyx. The external wall and parts of the dissepimentarium are often eroded in the large specimens. The mean tabularium diameter is 14 mm (maximum 21 mm). There are 45 septa in average (maximum 60; Fig. 6 ). The major septa are straight or slightly wavy in the dissepimentarium. They are usually long (up to 3/4 of the corallum diameter) but can be withdrawn or amplexoid in some cases ( Fig. 5D, G ). Despite their length, they do not reach the axis and leave a free zone of about 5 mm in diameter in the centre of the tabularium. The counter septum usually enters into this central zone. The cardinal septum is sometimes slightly shorter than its neighbours. The minor septa are long (1/2–3/4 of the length of the major septa) and sinuous, particularly in the dissepimentarium. They are contratingent or contraclinant. Some of them are intercepted by second order lonsdaleoid dissepiments. The thickness of the septa is variable, even in one specimen. The thickening occurs mainly in the cardinal quadrants but the counter quadrants are also affected in some specimens. The cardinal fossula is variably marked. Alar fossulae occur occasionally in small sized sections (juvenile stages). The dissepimentarium counts 4–6 rows of concentric interseptal dissepiments (maximum 14 in large specimens). In the latter, the inner rows can be V-shaped and herringbone. The inner row is commonly thickened, particularly in the cardinal quadrants. Some incomplete rows of first and second order lonsdaleoid dissepiments are present in large specimens ( Fig. 5M ). The external wall is regular and thin. In longitudinal section, the tabulae are usually complete and regularly spaced ( Fig. 5J 2 , L). They are typically mesa-shaped, the central part being flat and rising 1–2 mm from the peripheral edge of tabulae. The dissepiments are narrow, often high and steeply inclined (70–80°) towards the tabularium. There are 10–12 tabulae and 10–15 dissepiments per centimetre in longitudinal section.

Remarks. —In addition to size variation, the variability is extreme in this species and affects all the skeletal elements. The length and thickness of septa can double, even in the same specimen. The cardinal fossula varies from a shallow depression occupied by a long cardinal septum, to an opened fossula edged by curved cardinal-lateral septa and occupied by short and thick septa, and to a long and narrow keyhole-shaped fossula incised in the dissepimentarium. The morphology of the juvenile stages varies from zaphrentoid pattern to amplexoid forms ( Fig. 5D ) or stages with radially disposed long septa ( Fig. 5K ). Also, the dissepimentarium varies from 0 to 20 rows of dissepiments—mainly interseptal but with common lonsdaleoid dissepiments of both orders in large specimens. This plasticity might indicate more than one species but no discrete character allows a clear separation between different forms, all being continuous and all the possible intermediate forms occur. Moreover the quantitative data (e.g., diameter versus number of septa; Fig. 6 ) form a single continuum. All of them are commonly observed in the topotypic material of C. flexuosum (Edouard Poty, personal communication, May 2013). Further analysis based on the abundant French and Belgian material might refine the definition of C. flexuosum .

The specimens investigated here share with C. flexuosum ( Goldfuss, 1826) : (i) a long counter septum, (ii) sinuous “flexuous”) septa, (iii) contratingent or contraclinant minor septa, (iv) a narrow dissepimentarium (comparatively to other species, see below). Chwieduk (2005) excluded from C. flexuosum corals with long and thick septa in the juvenile stages, a short cardinal and a long counter septum. However these morphological variations are common within C. flexuosum and do not justify a new species. C. flexuosum has dimensions similar to those of C. cylindricum Onoprienko, 1979b but the latter has straight septa and minor septa less contratingent.

Stratigraphic and geographic range.— Campophyllum flexuosum is common in the uppermost Famennian ( Siphonodella praesulcata Conodont Zone ) in the Namur-Dinant Basin, Aachen vicinity ( Germany) and Avesnois (N France; Poty 1984), in Pomerania ( Campophyllum sp. A ; Chwieduk 2005) and possibly in the Holy Cross Mountains (juvenile stage named? Campophyllum sp. figured by Berkowski 2002).

Figures

Fig. 5. Cyathophylline Campophyllum flexuosum (Goldfuss, 1826) (A–M) and hetophylline Pseudoendophyllum sp. (N–Q) corals from the uppermost → Famennian (Strunian) of Zonguldak and Bartin areas, Topulca (A, B, D–I, K), Esenpınar (C, J), Gökgöl (L, M), and Dallıca (N–Q) sections, Turkey. A. ET.11.16.b, TS. B. ET.11.17.I, TS. C. EV.3.2, TS. D. ET.11.16.V’, TS. E. ET.11.16.b, TS. F. ET.11.16.IV.b, TS. G. ET.11.18, TS. H. ET.11.18, TS. I. ET.11.13.II.a, TS. J. EV.3.5, TS (J1), LS (J2). K. ET.11.16.V, TS. L. G.3.17.I, LS. M. G.3.15, TS, close-up view of the dissepimentarium. N. D.2.1.II, TS. O. D.2.4.I, TS. P. D.2.2.I.a, successive TS (P1, P2). Q. D.2.2.I.b, LS. Scale bar 5 mm for all specimens except D, 2.5 mm and M, 3.75 mm.

Fig. 6. Scatter diagram showing the number of septa plotted against corallite diameter for Campophyllum flexuosum (Goldfuss, 1826) and Campophyllum sp.

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.