The mechanoreceptors of the trilobite larva of Limulus polyphemus (Linnaeus, 1758) (Merostomata: Xiphosurida: Limulidae)

Abstract

Abstract Three types of mechanoreceptors were found on the cuticle of the first post-hatching instar of the trilobite larva of Limulus polyphemus (Linnaeus, 1758) examined by scanning electron microscopy: 1) tactile sensilla on the margin of the carapace of the prosoma; 2) sensilla, adapted to detect near-field sound energy in the form of particle motions and water currents, on the dorsal surface of the carapace covering the prosoma; 3) sensilla, having a helical structure of unknown function and not seen before, on the walking legs and pusher. The morphology of the mechanoreceptors of L. polyphemus, specifically the sensilla capable of sensing particle motions, may shed some light on the mechanisms of near-field sound or particle motion detection of these Jurassic “living fossils.”