A new crinoid morphotaxon from the Silurian (Llandovery) of SW Scotland (Ayrshire)

There is little known of the diversity of Silurian crinoids in Scotland. Rather than wait in hope for a new Lagerstätte, our knowledge of the fauna can be improved by recognizing imperfectly preserved specimens, such as disarticulated columnals. Pentagonopentagonalis (col.) annulus sp. nov. is here recorded from the Llandovery (Rhuddanian) Mulloch Hill Sandstone Formation of Ayrshire. It is known only from disarticulated columnals, most without counterpart, and rare pluricolumnals. The column is xenomorphic, and columnals can vary from pentagonal (probably proximal) to rounded or circular (more distal?), each with a moderately broad lumen that is similarly shaped. There is no areola and the articulation is radial symplectial. Pluricolumnals are heteromorphic, perhaps N3231323. This morphospecies is described to demonstrate something of the wealth of information and inference that may be gleaned from even the most unpromising material.