Crinoid

aff. Aphelecrinus

• Devonian
• Devils Gate Limestone
• Eureka, Nevada, USA

Size: 5.5 cm crown

This is a very unusual crinoid and likely a new taxon. Based on assessment by both experienced amateurs and profesionals (Gabe Ward, Lincoln Shoemaker, George McIntosh), it closely resembles the genus Aphelecrinus; a cladid with a conical calyx and prominent interradial notches, uniserial pinnulate arms with axillary primibrachials and isotomous branching halfway up the crown, and a round stem. However, this specimen also bears at least one additional branching higher up in the arms, possibly endotomously, and doesn't seem to have a looped anal sac typical of the genus. In addition, Aphelecrinus is predominantly a Mississippian genus, with a few possibly reported from the Devonian of the UK. This crinoid is either a new species of Aphelecrinus and among the earliest in North America, or a new genus altogether.

Note the unusually small arm in the C ray, which seems to be a regenerating arm following damage/predation. The crinoid's anal sac is visible just behind it.