Denaea sp.

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 : 914-915

Denaea sp.

Fig. 14E .

Material.—Four teeth from upper Viséan of Todowa Grząba, north of Ostrówka Quarry, Gałęzice Region, Holy Cross Mountains, Poland (sample TG-D); MWGUW/Ps/11/23.

Description.—There are a few poorly preserved five-cusped cladodont teeth in the material from Todowa Grząba which are generally similar to D. cf. fournieri , but larger (about 2.5 mm across the base) and with more robust cusps. They may belong to a larger species of Denaea , some other falcatid, or an undetermined symmoriiform.

Order Ctenacanthiformes Glikman, 1964

Family indet.

Genus indet.

“ Ctenacanthus ” costellatus Traquair, 1884

Fig. 9D, E .

1884 Ctenacanthus costellatus Traquair ; Traquair 1884: 3–8, pl. 2.

1936 Ctenacanthus costellatus Traquair, 1884 ; Moy-Thomas 1936: 762–771, text-figs. 1, 2, pl. 1: a, b.

2002 “ Ctenacanthus ” costellatus Traquair, 1884 ; Ginter 2002, figs. 4A, 5.

2010 “ Ctenacanthus ” costellatus Traquair, 1884 ; Ginter et al. 2010: 77–78, fig. 71.

Material.—One tooth from upper Viséan, Ticknall, Derbyshire, England, UK and one from upper Viséan of Todowa Grząba, north of Ostrówka Quarry, Gałęzice Region, Holy

Cross Mountains, Poland (sample TG-D); NHMUK PV P73290, ZPAL P.IV/256.

Description.—There are two relatively large but incomplete teeth in the analysed material, one (from Ticknall; Fig. 9D ) with the mesio-distal dimension probably exceeding 2 mm when complete, and another (from Todowa Grząba; Fig. 9E ) probably no smaller than 7 mm.

The smaller tooth has about 2/3 of the base preserved, with all of the important features available for observation. The lingual part of the base is broad and rounded, and there are two prominent, widely spaced, orolingual buttons. To these buttons correspond two separate basolabial projections, semi-circular in aboral view, with a shallow median depression lying between them. The crown in this specimen is heavily damaged, but the fragment that remains reveals that it was cladodont, with three lateral cusps on each side (if the tooth was symmetrical). The outermost cusps appear to be larger than the intermediate two. The labial side of the cusps is covered with strong cristae. On the most complete of the lateral cusps, the two cristae converge and reach the tip as one ( Fig. 9D 2 ). The cristae on the lingual side are more gentle and sub-parallel.

In the larger tooth, only half of the crown is preserved; the base is completely destroyed. The crown is cladodont, with four lateral cusps on each side. Again, the outermost cusp is larger than the intermediate ones. The labial side of the crown is covered with strong cristae, converging at various heights, and the lingual side bears more delicate cristae. The shallow depression at the base of the labial side of the median cusp ( Fig. 9E 2 ) suggests, that there might also have been a basolabial depression in the base, as in the smaller tooth.

Remarks.—Although incomplete, the two teeth can confidently be considered as smaller and larger morphotypes belonging to the same species, particularly because of the form and ornamentation of the crown. Moreover, the combined characters of these two specimens show similarities with the teeth associated with the articulated material of “ Ctenacanthus ” costellatus Traquair, 1884 , from the Viséan of Glencartholm, Scotland, UK (NHMUK PV P20144-5; Ginter et al. 2010: fig. 71). The size of those teeth is from ca. 2 to 8 mm across the base. They have two orolingual buttons, two semi-circular basolabial projections ( Ginter 2002: fig. 5C) separated by a shallow depression, with strong cristae converging upwards over the labial side of the cusps, and more gentle, subparallel cristae on the lingual side. The smaller teeth have only two lateral cusps on each side of a prominent medial cusp, but the largest illustrated tooth-fragment (Ginter et al. 2010: fig. 71C) displays at least three on one side (there is a space for a fourth one). Also one of the early illustrations by Moy-Thomas (1936: pl. 1b) shows strong cristae and three cusps on each side.

To us, it appears very probable that the teeth from Ticknall and Todowa Grząba actually belong to “ C. ” costellatus . If our reasoning is correct, this would be the first report of that important species outside of the type locality.

Stratigraphic and geographic range.—Both articulated specimens were found in the Viséan of Glencartholm, Scotland, UK (Traquair 1884; Moy-Thomas 1936); isolated teeth are known from the upper Viséan, Ticknall, Derbyshire, England, UK and Holy Cross Mountains, Poland (this paper).

Figures

Fig. 14. Chondrichthyan teeth from the upper Viséan of Todowa Grząba, north of Ostrówka Quarry, Gałęzice Region, Holy Cross Mountains, Poland. A. Euselachii indet. 2, MWGUW/Ps/11/21, in lateral (A1), labial (A2), lingual (A3), and oral (A4) views. B. Euselachii indet. 1, MWGUW/Ps/11/22, in labial (B1) and lingual (B2) views. C. Bransonella nebraskensis (Johnson, 1984), ZPAL P.IV/215, in lateral (C1) and labial/aboral (C2) views. D. Orodont-like crushing tooth, ZPAL P.IV/233, in oral/lingual view. E. Denaea sp., large tooth, MWGUW/Ps/11/23, in labial view.

Fig. 9. Chondrichthyan teeth from the upper Viséan of Ticknall, Derbyshire, England, UK (A–D) and Todowa Grząba, north of Ostrówka Quarry, Gałęzice Region, Holy Cross Mountains, Poland (E). A. Bransonella nebraskensis (Johnson, 1984), NHMUK PV P73288, in labial (A 1) and lingual (A2) views. B, C. Thrinacodus dziki sp. nov. B. NHMUK PV P66779, in lateral (B 1) and labial (B2) views. C. NHMUK PV P73289, in oral view. D, E. Teeth similar to “Ctenacanthus” costellatus Traquair, 1875. D. NHMUK PV P73290, in oral (D 1), lateral/labial (D2), and lateral/lingual (D3) views. E. ZPAL P.IV/256, in oral (E 1) and labial (E2) views.

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).