Capitella caribaeorum sp. nov., a new capitellid polychaete from the Caribbean Lynda M. Warren Department of Life Sciences, Goldsmiths' College, Rachel McMillan Building, Creek Road, London SE8 3BU J. David George Department of Zoology, British Museum (Natural History), Cromwell Road, London SW7 5BD Introduction The capitellid polychaete described below has been found intertidally amongst decaying mangrove leaves in southern Florida, Cuba and St Lucia. It forms a network of galleries, lined with mucus and faeces (Fig. la), through the surface layers of organic debris accumulated around mangrove roots. The worm has been cultured in agar through many generations (George, 1975) and its behaviour and life history have been elucidated from observations made both in the field and in the laboratory (George, 1984). Initially it was thought that the worm could be assigned to Capitella giardi (Mesnil, 1897), but subsequent study has shown that sufficient morphological, behavioural and physiological differences exist to warrant erection of a new species. The description given below is based on adults collected from the natural habitat and supplemented by observations made on specimens from laboratory culture. No morphological differences were detected between worms from the wild populations and those from a culture that had been maintained in the laboratory for five years. Specimens collected in the field were fixed in 10% neutralized commercial formalin in sea water for 48 hours before storage in 80% ethyl alcohol. Specimens derived from the cultures were either relaxed by slow addition of alcohol to sea water containing the worms prior to formalin fixation or were anaesthetized by slow addition of glutaraldehyde before fixation in 2-5% glutaraldehyde in 0-1 M phosphate buffer (pH 7-2) with 0-5 M sucrose. Material was dehydrated through the alcohols prior to examination by optical or scanning electron microscopy (SEM). Specimens to be examined by SEM (Hitachi S-800) were either air-dried using diethyl ether or acetone, or dried in an Edwards-Pearse tissue dryer EPD3, using acetone and liquid CO 2 , before coating with gold/palladium in a Polaron sputter coating unit. Description of new species Capitella caribaeorum sp. nov. TYPES. The holotype is a fully grown specimen containing oocytes. The paratypes include specimens that have not reached physical maturity. The holotype (registration no. BM(NH) ZB. 1985. 191) and paratypes (registration nos. BM(NH) ZB. 1985. 192-196) are deposited in the collections of the British Museum (Natural History). Further paratypes have been deposited in the collections of the National Museum of Natural History, Smithsonian Institution, Washington, D.C., U.S.A. and in the Australian Museum, Sydney. TYPE LOCALITY. Southern Florida red mangrove (Rhizophora mangle Linnaeus) swamp, Matheson Hammock, Miami, Florida, U.S.A. MORPHOLOGY. The species is small with fully grown individuals measuring up to 20 mm in length and 0-7 mm in width across the mid-thorax. The body is divided into a relatively muscular Bull. Br. Mus. not. Hist. (Zool.) 50(2): 1 17-125 Issued 26 June 1986
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