Denaea cf. fournieri Pruvost, 1922

Ginter, Michał, Duffin, Christopher J., Dean, Mark T. & Korn, Dieter, 2015, Late Viséan pelagic chondrichthyans from northern Europe, Acta Palaeontologica Polonica 60 (4), pp. 899-922 : 909-911

Denaea cf. fournieri Pruvost, 1922

Figs. 7A–F , 10A–E , 12 .

Material.—Twenty three teeth from upper Viséan of Cawdor Quarry, Matlock, Derbyshire, England, UK (samples Cawdor 1, 2, 4, 7–14); 33 from upper Viséan of Todowa Grząba, north of Ostrówka Quarry, Gałęzice Region, Holy Cross Mountains, Poland (sample TG-D); 33 from upper Asbian, Goniatites fimbriatus Ammonoid Zone, Westenfeld Quarry , Germany (sample C12); NHMUK PV P73276–81, MWGUW/Ps/11/1–5, MWGUW/Ps/11/12–17, MWGUW/ Ps/7/5, ZPAL P.IV/219–221.

Description.—The tooth crown usually consists of five or seven cusps (the prominent median cusp and two or three lateral cusps on each side, e.g., Fig. 12F and A , respectively), but in the material from Westenfeld a few teeth were found with nine cusps (four lateral cusps on each side; Fig. 10B, E ). There are also specimens with an additional lateral cusp on one side ( Fig. 12C ). In five- and seven-cusped teeth the outer lateral cusps are the highest. In nine-cusped teeth the third pair from the median cusp is the highest.

The median cusp is long and slender, sigmoidal in lateral view, often slightly inclined laterally (distally?), and sub-circular in cross section. The whole cusp, except for the uppermost fifth, is ornamented with dense sub-parallel cristae (e.g., Fig. 12F ). In some rare cases the cristae coalesce ( Fig. 12B, C ), and sometimes disappear earlier than the others

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Fig. 12I ). There is no distinct lateral carina; only the lateral cristae run continuously to the cusp apex. The ornamentation of the lateral cusps is similar, but usually there is no uppermost unornamented area.

The base is roughly pentagonal (in oral/aboral view), with rounded angles ( Fig. 12G 3 , H, J 2 ). Sometimes, especially in the material from Westenfeld, the lateral angles form wings” directed lingually ( Fig. 10C ). The orolingual button is oval, sometimes almost split in two by the openings of the main basal canal which are situated on the lingual and labial sides of the button ( Fig. 7F ). It appears to be a rule that the lingual foramen in symmetrical specimens lies exactly in the midline ( Fig. 12G 1 ), whilst in those with the median cusp inclined distally, the foramen is slightly displaced towards the distal side ( Fig. 12A 3 , A 4 , F 2 , F 3 ). In the smaller specimens such as Fig. 12G ) the button seems to be more compact and distinct and in the larger ones its boundaries are rather vague.

On the aboral side of the base there is a third opening of the main basal canal, situated roughly in the centre ( Figs. 7C , 12H ), and probably yet another, small perforation close to the basolabial projection. The latter foramen is rarely seen, but was revealed in thin section. The basolabial projection is tubercle-like, squarish in cross-section, and not wider than the basal part of the median cusp ( Fig. 12J ).

The size of the teeth of D. cf. fournieri from Todowa Grząba and Westenfeld is usually confined to the interval 0.6–1.5 mm (mesio-distal dimension of the base), the five-cusped specimens being smaller than the seven-cusped ones. However, in the material from Westenfeld there occurs a seven-cusped tooth whose size reaches 2 mm. It is interesting that all the specimens from Cawdor Quarry ( Fig. 7A–F ) are similar to the smaller teeth from Todowa Grząba. Their size is about 0.6–0.7 mm, all of them are five-cusped, symmetrical, and have relatively compact buttons situated at the lingual rim of the base. Such morphological uniformity, and especially the lack of seven-cusped specimens (please note that the illustrated specimens come from two different horizons), leads to the suspicion that the material from Cawdor Quarry might actually represent a different species to that present in Todowa Grząba and Westenfeld.

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Remarks.—Despite the problems listed in the remarks concerning the genus, quite a few morphological features of the teeth of D. fournieri can be determined from the photograph provided by Fournier and Pruvost (1928: figs. 8, 9) and the recent re-examinations of the material (MG personal observation 1998; Ivanov 1999; Ivanov and Derycke 2005: fig. 1A–I). These features were summarised by Ginter and Hansen (2010: 29) and Ginter et al. (2010: 65). The comparative analysis suggests that of all known Viséan Denaea- like teeth, the series of Denaea cf. fournieri found at Todowa Grząba and at the Westenfeld Quarry are morphologically the closest to the type material and we believe that they actually represent the type species.

Stratigraphic and geographic range.— Denaea fournieri articulated specimens were described from the lower Viséan (Moliniacian) of Denée, Belgium ( Fournier and Pruvost 1928); isolated teeth similar to those of D. fournieri , here referred to as D. cf. fournieri , were noted from the upper Viséan of the Holy Cross Mountains, Poland; Derbyshire, England, UK; and the Rhenish Mountains, Germany (this paper). Unexpectedly, Derycke et al. (2005) and Ivanov and Derycke (2005) do not mention any species of Denaea , except the specialised D. wangi , from the upper Viséan of Royseux, Belgium.

Figures

Fig. 7. Cladodont teeth from the upper Viséan of Cawdor Quarry, Matlock, Derbyshire, England, UK; sample Cawdor 9 (A–C), 11 (D–G). A–F. Denaea cf. fournieri Pruvost, 1922. A. NHMUK PV P73276, in lateral (A 1), oral (A 2), lingual (A 3), and labial (A 4) views. B. NHMUK PV P73277, in oral (B 1) and lingual (B 2) views. C. NHMUK PV P73278, in aboral (C 1) and aboral/labial (C 2) views. D. NHMUK PV P73279, in labial (D 1), oral (D 2), and oblique lingual (D 3) views. E. NHMUK PV P73280, in aboral (E 1) and labial (E 2) views. F. NHMUK PV P73281, in oral (F 1) and lingual (F 2) views. G. Squatinactis caudispinatus Lund and Zangerl, 1974, narrow tooth with broken base (NHMUK PV P73282), in labial (G ), oral (G ), and lingual (G ) views.

Fig. 10. Chondrichthyan teeth from the upper Viséan of the Westenfeld Quarry, Rhenish Mountains, Germany. A–E. Denaea cf. fournieri Pruvost, 1922. A. MWGUW/Ps/11/1, in labial (A 1), lingual (A 2), and oral (A 3) views. B. MWGUW/Ps/11/2, in oral (B 1), lingual (B 2), and labial (B 3) views. C. MWGUW/ Ps/11/3, in oral view. D. MWGUW/Ps/11/4, in labial/aboral view. E. MWGUW/Ps/11/5, in lingual (E 1) and oral (E 2) views. F, G. Thrinacodus cf. gracia Grogan and Lund, 2008). F. MWGUW/Ps/11/6, in oral (F ) and lateral (F ) views. G. MWGUW/Ps/11/7, in lateral (G ) and oral (G ) views.

Fig. 12. Teeth of phoebodontid chondrichthyan Denaea cf. fournieri Pruvost, 1922, from the upper Viséan of Todowa Grząba, north of Ostrówka Quarry, Gałęzice Region, Holy Cross Mountains, Poland. A. ZPAL P.IV/221, in lateral (A 1), labial (A 2), oral (A 3), and lingual (A 4) views. B–D. MWGUW/Ps/11/12, MWGUW/Ps/11/13, and MWGUW/Ps/11/14, respectively, in labial views. E. MWGUW/Ps/11/15, in lateral view. F. MWGUW/Ps/11/16, in labial (F 1), lingual (F 2), and oral (F 3) views. G. ZPAL P.IV/219, in lingual (G 1), lateral (G 2), and oral (G 3) views. H. ZPAL P.IV/220, in aboral/labial view. I. MWGUW/ Ps/11/17, in labial view. J. MWGUW/Ps/7/5, in labial (J ), aboral (J ), and aboral/lateral (J ) views.

Fig. 3. A. Position of Westenfeld Quarry against the outline of Mississippian outcrops in the northern Rhenish Mountains. B. Fragment of the stratigraphic column of the Westenfeld Quarry showing position of sample C12, studied in this paper.

Fig. 2. A. Sketch map showing Viséan limestone quarries in the area of Matlock, Derbyshire, England, UK.B. Stratigraphic column of the rocks exposed in Cawdor Quarry. Numbered arrows, positions of the studied samples (Cawdor 1–14).

Fig. 1. Palaeogeographic reconstruction of northern Europe in the Viséan, showing positions of the areas which yielded pelagic chondrichthyan microfossils described in this paper. 1, Derbyshire, England, UK (Cawdor, Steeplehouse, and Ticknall Quarries); 2, Rhenish Mountains, Germany (Westenfeld Quarry); 3, Holy Cross Mountains, Poland (Todowa Grząba). Modified from Ziegler (1989).

Fig. 4. A. Position of Todowa Grząba on the outline of Palaeozoic core of the Holy Cross Mountains (inset: solid black, Carboniferous outcrops) and on the sketch geological map of the area between the NE edge of the Ostrówka Quarry and the Gałęzice Village. B. Section through the NE edge of the Ostrówka Quarry and Todowa Grząba with the upper Viséan carbonate part enlarged, modified from Bełka and Skompski (1988: figs. 1, 2, 4).