Diverse Gyracanthus Spine Morphologies From the Jarrow Assemblage (Pennsylvanian), County Kilkenny, Ireland

Abstract

Gyracanthid fish spines are described in detail for the first time from the Pennsylvanian (Langsettian)-aged Jarrow Assemblage in southeast Ireland. The spines are divided into pectoral, pelvic and anal spine morphotypes. The Jarrow gyracanthid is assigned to Gyracanthus sp. based on the morphology of its pectoral spines, which display U-shaped transections that possess ornament ridges on the exsertion area that do not change orientation distally along the length of the spine.