PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON 112(4):695-713. 1999. New records of isopods from the Indian River Lagoon, Florida (Crustacea: Peracarida) Brian Kensley and Marilyn Schotte Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560, U.S.A. Abstract. — Fifteen species of isopod are recorded for the first time as oc-curring in the Indian River Lagoon. Two species are described as new: the janirid asellote lais floridana, n. sp., which occurs commensally with Sphae-roma terebrans in low salinity water, and the sphaeromatid flabelliferan Sphae-romopsis sanctaluciae, n. sp., which is also recorded from the Orange River, Lee County, Florida, and from Islas de Juventud, Cuba. A brief discussion of protogyny in the sphaeromatid Paradella dianae is included. The Indian River Lagoon, Florida, is the most biologically diverse estuarine system on the east coast of North America. As part of the Intra-coastal Waterway, it is subject to heavy usage by commercial and sport/ recreational water traffic, and has seen heavy residential development along its shores. Given its important mixed-use re-sources, intensive study of the lagoon has been carried out for some time (see Rich-ards 1995). Ongoing investigations by the authors of the crustacean fauna of the la-goon have revealed a number of isopod species not recorded in earlier studies (e.g., Kensley, Nelson, & Schotte 1995), al-though some of these may be known from the wider Florida region (see Camp, Lyons, & Perkins 1998). In part, these new records are the result of sampling in a wide variety of habitats, both in the main lagoon as well as in its tributary rivers and in the inlets that open to the sea. Twenty-five marine isopod species had previously been recorded from the IRL. The present paper documents 15 additional species and adds to the knowl-edge of the biodiversity of the Indian River Lagoon. Restricted synonymies, which in-clude the original description plus any Flor-ida records, and references that contain ful-ler synonymies are provided for most spe-cies. Collecting stations designated 'FTP' are those of the authors'. Unless otherwise stated, all material is deposited in the col-lections of the National Museum of Natural History, Smithsonian Institution. Suborder Anthuridea Family Anthuridae Cyathura polita (Stimpson, 1855) Anthura polita Stimpson, 1855:393. — Har-ger, 1880:398-402, pi. XI, figs. 68-69. Cyathura polita: Burbanck, 1959:507. — Kruczynski & Subrahmanyam, 1978: 93.— Camp et al., 1998:132. Material examined. — 1 $ , FTP-1, St. Lu-cie River, rotten wood in mangroves, 0.5 m, salinity 15-20 ppt., 29 May 1995.— 1 9, FTP-22, Fort Pierce, Taylor's Creek near Rt. 1 , rotten wood on muddy bank with cat-tails and Spartina, intertidal, 10 ppt., 25 Apr 1996. Previous records. — East coast of Amer-ica from the Gulf of Mexico to Canada. Mesanthura pulchra Barnard, 1925 Mesanthura pulchra Barnard, 1925:145, fig. 9e.— Kensley & Schotte, 1989:49, fig. 19b; 52-53.— Camp et al., 1998:132. Mesanthura decorata Menzies & Glynn, 1968:26, fig. 8a-i.