Integrative taxonomy of crustacean y-larvae (Thecostraca: Facetotecta) using laboratory-rearing and molecular analyses of single specimens, with the description of a new vermiform species

AbstractFacetotecta, the taxon established for ‘y-larvae’, is the last major crustacean group for which the adult stage remains unknown. With only 14 described nominal species, all in the genus Hansenocaris, their incompletely known life cycle, small size and dearth of molecular data have hampered assessments of their true species diversity. Based on field studies during which > 11 000 y-larvae were sampled, a new integrative approach for studying the taxonomy of y-larvae is outlined. It focuses on last-stage nauplii and y-cyprids and includes methods for rearing lecithotrophic y-larvae for documenting the morphology of specimens with live photomicroscopy and scanning electron micros…