Estimated predation rate of the stalked bourgueticrinid (Crinoidea) Democrinus from Roatán, Honduras

Abstract

Crinoids have the ability to regenerate their crowns when arms are autotomized or bitten off by predators. The evidence of predation is visible in many populations of crinoids, including the deep water stalked crinoid Democrinus off the coast of Roatán, Honduras. Throughout the videos taken in a submersible, many individuals displayed arms that are significantly shorter relative to their stalk lengths than the full‐grown adults in the area, indicating arm regeneration. Some individuals were missing crowns completely, strongly suggesting predation by fishes. Our calculated predation rate of 17.25% including individuals missing a crown or regenerating their arms in situ is significantly greater than that rates determined in previous studies of predation on Democrinus. Copyright © 2016 John Wiley & Sons, Ltd.

A diverse crinoid fauna (Echinodermata, Crinoidea) from the Lower Eocene of the Gulf of Languedoc (Corbières, Aude, southern France)

“…This is the case with Pseudoconocrinus from four sites: Lavade, the ancient Tuilerie de Fontcouverte, Le Coucou and Terro Blanco. However, brachials are few and underrepresented, probably because they are the first to dissociate, but also because the crown of arms is the preferred target of predators (Paschall and Waters 2016;Veitch and Baumiller 2021). At other sites (Le Cabagnol, La Commanderie, Les Rives and L'Auzerdier), hydrodynamic selection eliminated the smallest ossicles and only the largest brachials (IBr2ax), columnals and cups of Pseudoconocrinus remain present despite the abundance of material.…”