Galeus sp.

Underwood, Charlie J. & Schlögl, Jan, 2013, Deep-water chondrichthyans from the Early Miocene of the Vienna Basin (Central Paratethys, Slovakia), Acta Palaeontologica Polonica 58 (3), pp. 487-509 : 489-490

Galeus sp.

Fig. 4A–F.

Material.—Ten incomplete teeth including SNM Z 27432 to SNM Z 27437.

Description.—All teeth of this species are very small, being below 0.7 mm in width or height and represent four lowcrowned lateral teeth and one high−crowned anterior tooth. The lateral teeth are either a similar height to width, or slightly wider than high, while the anterior tooth is higher than wide. The teeth are highly cuspate, with between 5 and 10 cusps. The degree of symmetry of the lateral teeth is very variable, with teeth ranging from close to bilaterally symmetrical to strongly asymmetrical, with the main cusp flanked by three cusplets on the mesial side and only one on the distal side; the

http://dx.doi.org/10.4202/app.2011.0101

anterior tooth is strongly angled mesially, with the main cusp angled in that direction. The main cusp is, where preserved, less than twice the height of the innermost lateral cusps in the lateral teeth, but is proportionally very large and high in the anterior tooth. The labial face of the cusps of lateral teeth is smooth and almost flat, being separated from the lingual face by a very well developed cutting edge, while below the cusps on the labial face of the crown, short and sharp−edged folds are present, that expand into small swellings at the base of the crown basal face. In the anterior tooth, widely spaced and strong folds extend most of the height of the main cusp, with some bifurcating near the crown base. Close to the base of the crown, a fine polygonal ornament is present both on and between the folds of all teeth. The lingual face of the cusps is convex and ornamented by several weak but sharp edged folds, which reach almost to the cusp apex but do not reach the base of the crown. Where preserved, the root is low and “V” shaped, without a nutritive groove. The lateral and labial faces of the root are concave, and flare towards the basal face, from which they are separated by a sharp angle. A major foramen is present in the centre of the root labial face, with rare, smaller foramina also present. The root basal face is weakly convex and has a number of foramina, which are variable in size and shape and irregularly distributed.

Remarks.—These teeth all appear to belong to a single species of highly heterodont syliorhinid. The heterodonty, highly cuspate lateral teeth and pattern of ornament is seen in two extant genera, Galeus and Apristurus Garman, 1913 . The differentiation of these genera by their dentition is discussed by Herman et al. (1990) and Adnet (2006). Despite the poor quality of material available here, the degree of heterodonty, lack of a nutritive groove in the root and asymmetry of the anterior tooth suggest that these specimens should be assigned to Galeus .