biostudies-literatureBieler RUS National Science FoundationNegaunee Foundation and The Grainger FoundationCoral reef-related studies in the Florida Keys were supported by the Paul M. Angell Family Foundatione15854https://www.ebi.ac.uk/biostudies/studies/S-EPMC10569170biostudies-literatureUnknown11Vermetid worm-snails are sessile and irregularly coiled marine mollusks common in warmer nearshore and coral reef environments that are subject to high predation pressures by fish. Often cryptic, some have evolved sturdy shells or long columellar muscles allowing quick withdrawal into better protected parts of the shell tube, and most have variously developed opercula that protect and seal the shell aperture trapdoor-like. Members of <i>Thylacodes</i> (previously: <i>Serpulorbis</i>) lack such opercular protection. Its species often show polychromatic head-foot coloration, and some have aposematic coloration likely directed at fish predators. A new polychromatic species, <i>Thylacodes bermudensis</i> n. sp., is described from Bermuda and compared morphologically and by DNA barcode markers PeerJReplacing mechanical protection with colorful faces-twice: parallel evolution of the non-operculate marine worm-snail genera <i>Thylacod</i>es (Guettard, 1770) and <i>Cayo</i> n. gen. (Gastropoda: Vermetidae).PMC10569170DBI-0841760/0841777Collins TMGolding RBieler RHealy JMGranados-Cifuentes CSierwald PRawlings TAfalseReplacing mechanical protection with colorful faces-twice: parallel evolution of the non-operculate marine worm-snail genera <i>Thylacod</i>es (Guettard, 1770) and <i>Cayo</i> n. gen. (Gastropoda: Vermetidae).Vermetid worm-snails are sessile and irregularly coiled marine mollusks common in warmer nearshore and coral reef environments that are subject to high predation pressures by fish. Often cryptic, some have evolved sturdy shells or long columellar muscles allowing quick withdrawal into better protected parts of the shell tube, and most have variously developed opercula that protect and seal the shell aperture trapdoor-like. Members of <i>Thylacodes</i> (previously: <i>Serpulorbis</i>) lack such opercular protection. Its species often show polychromatic head-foot coloration, and some have aposematic coloration likely directed at fish predators. A new polychromatic species, <i>Thylacodes bermudensis</i> n. sp., is described from Bermuda and compared morphologically and by DNA barcode markers 2023-01-01T00:00:00Z20232026-04-08T14:12:04.866Z2025-04-19T17:33:03.443ZS-EPMC105691703784205710.7717/peerj.15854