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2 Acta Geologica Polonica

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Symmoriiform sharks from the Pennsylvanian of Nebraska

Ginter M.

Acta Geologica Polonica

2018

Vol. 68, no. 3

391--401

The Indian Cave Sandstone (Upper Pennsylvanian, Gzhelian) from the area of Peru, Nebraska, USA, has yielded numerous isolated chondrichthyan remains and among them teeth and dermal denticles of the Symmoriiformes Zangerl, 1981. Two tooth-based taxa were identified: a falcatid Denaea saltsmani Ginter and Hansen, 2010, and a new species of Stethacanthus Newberry, 1889, S. concavus sp. nov. In addition, there occur a few long, monocuspid tooth-like denticles, similar to those observed in Cobelodus Zangerl, 1973, probably representing the head cover or the spine-brush complex. A review of the available information on the fossil record of Symmoriiformes has revealed that the group existed from the Late Devonian (Famennian) till the end of the Middle Permian (Capitanian).

Some observations on Denaea fournieri (Chondrichthyes, Symmoriiformes) from the Lower Carboniferous of Belgium

Maisey J.

Acta Geologica Polonica

2008

Vol. 58, no. 2

185-190

Preliminary observations are presented concerning endoskeletal morphology in the Lower Carboniferous symmoriiform shark Denaea fournieri, and some problems in the original description are highlighted. D. fournieri almost certainly possessed a tropibasic braincase and its cranial morphology agrees in most respects with that observed in other symmoriiforms, although it had an extremely narrow ethmoidal region and may have lacked supraorbital cartilages. Its pectoral fins were probably similar to those of other symmoriiforms, and the radialbearing margin of its metapterygium most closely resembles that of falcatids and Stethacanthulus. Using Cladoselache as an outgroup, several apomorphic characters are identified in symmoriiform pectoral fins.