Ovicides julieae n. gen., n, sp (Nemertea : Carcinonemertidae) on xanthid crabs from the Great Barrier Reef, Australia

A new genus and species of symbiotic, semi-parasitic nemertean worm, Ovicid es julieae n. gen., n. sp., is described from the xanthid crabs Chlorodiell a nigra and C. xishaensis. The new genus possesses accessory stylet pouches and exhibits simultaneous hermaphroditism, features new to the family Carc inonemertidae. The new species has a relatively small anterior proboscis ch amber and small basis, yet it possesses the largest styler to basis ratio ( up to 0.650) reported far the family. It also has a flame cell pattern of a t least 2[(3+3)], which is different from those reported for two other spec ies. The worm occurred in a lightly granulated sheath on the abdominal ster na, pleopods, and clutches of its host, but few adult worms were found. The species exhibited a high host specificity and was more frequently found on C. nigra than on C. xishaensis (7.5 vs. 0.4%, overall prevalence, respecti vely). Worms were only found on female crabs, and worm intensity showed a m odest but significantly positive correlation with host size. Ovicides julie ae represents the second genus in the Carcinonemertidae, the fifth describe d carcinonemertid species from Australia, and the eleventh described specie s in the family.