Revision of the smiling worms, genus Prosorhochmus Keferstein, 1862, and description of a new species, Prosorhochmus belizeanus sp nov (Prosorhochmidae, Hoplonemertea, Nemertea) from Florida and Belize

Abstract

A new species of Prosorhochmus is described from Belize and Florida based on morphological, reproductive and sequence data. Similar to Prosorhochmus nelsoni (Sanchez, 1973), Prosorhochmus belizeanus sp. nov. is gonochoric and oviparous; all other species of Prosorhochmus are viviparous hermaphrodites. Prosorhochmus belizeanus sp. nov. differs from P. nelsoni by having significantly larger stylets and different arrangement of acidophilic cephalic glands. Sequence divergence between the two is 7.4% (16S) and 9.1% (COI), comparable to divergence from the viviparous hermaphroditic species. Prosorhochmus Keferstein, 1862 is revised based on re-evaluation of the type and voucher material as well as fresh specimens collected by Lis. We conclude that Prosorhochmus adriaticus Senz, 1993 is insufficiently described and cannot be distinguished from Prosorhochmus claparedii Keferstein, 1862. We re-establish Prosorhochmus korotneffi Burger, 1895 from its previous synonymization with P. claparedii and designate it as type species of Arhochmus gen. nov.