Seven new species of Tetranemertes Chernyshev, 1992 (Monostilifera, Hoplonemertea, Nemertea) from the Caribbean Sea, western Pacific, and Arabian Sea, and revision of the genus Author Cherneva, Irina https://orcid.org/0000-0002-5533-6527 Department of Invertebrate Zoology, Faculty of Biology, Moscow State University, Moscow, Russia Author Ellison, Christina I. https://orcid.org/0000-0002-1856-386X Oregon Institute of Marine Biology and Biology Department, University of Oregon, Charleston, OR, USA Author Zattara, Eduardo E. https://orcid.org/0000-0002-9947-9036 Instituto de Investigaciones en Biodiversidad y Medio Ambiente, Centro Regional Universitario Bariloche, Universidad Nacional del Comahue, Consejo Nacional de Investigaciones Cientificas y Tecnologicas, Bariloche, Argentina & Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA Author Norenburg, Jon L. https://orcid.org/0000-0001-7776-1527 Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA Author Schwartz, Megan L. https://orcid.org/0000-0001-5318-2838 School of Interdisciplinary Arts and Sciences, University of Washington, Tacoma, WA, USA Author Junoy, Juan https://orcid.org/0000-0002-6125-558X Departamento de Ciencias de la Vida, Facultad de Ciencias, Universidad de Alcala, Alcala de Henares, Spain Author Maslakova, Svetlana A. https://orcid.org/0000-0002-3629-6638 Oregon Institute of Marine Biology and Biology Department, University of Oregon, Charleston, OR, USA svetlana@uoregon.edu text ZooKeys 2023 2023-10-05 1181 167 200 http://dx.doi.org/10.3897/zookeys.1181.109521 journal article http://dx.doi.org/10.3897/zookeys.1181.109521 1313-2970-1181-167 E38531F280734B9EA3ECE05D03865AF5 7284D377F64253E0AF69CFBDBF89912A Tetranemertes hermaphroditica (Gibson, 1982) Nemertes hermaphroditicus Gibson, 1982: 227. Type material. No specimens of this species were available to us for morphological examination or DNA barcoding. Type material consists of the holotype: mature individual, full series of transverse and oblique sections, deposited at the Australian Museum, in Sydney, Australia (W.5880), collected by R. Gibson, 13 July 1975, western mid-reef flat, Heron Island, Capricorn Group. Diagnosis. Body color of living specimens dusky pink overall with translucent and colorless body margins, resembling T. antonina , T. arabica sp. nov., and T. majinbuui sp. nov. Tetranemertes hermaphroditica is the only species in the genus known to be a simultaneous hermaphrodite. Basis of central stylet is described to be cylindrical and rounded posteriorly, similar to that reported by Buerger (1895) for T. antonina , and unlike the posteriorly bilobed or deeply forked basis in other species of the genus, at least in larger individuals. Wide geographic separation also supports the distinctiveness of this species from all others. Habitat. Beneath a large fragment of dead coral ( Acropora sp.) partially embedded in clean coral sand. Geographic distribution. Heron Island, Australia. Etymology. The specific name refers to the fact that specimens of this species are hermaphrodites. Note that both Nemertes and Tetranemertes are of female gender ( Nemertes is a Greek nymph, daughter of the god Nereus). Consequently, the correct Latin ending of the specific epithet should be -a, not -us.