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 us. We conclude that Prosorhochmus adriaticus Senz, 1993 is insufficiently described and cannot be distinguished from Prosorhochmus claparedii Keferstein, 1862. We re‐establish Prosorhochmus korotneffi Bürger, 1895 from its previous synonymization with P. claparedii and designate it as type species of Arhochmus gen. nov.

Keywords:

• Nemertea
• Prosorhochmus
• Arhochmus
• smiling worms
• Cytochrome Oxidase I
• 16S rDNA

Acknowledgements

We thank Barbara Littman for assistance in preparing histological slides and cataloging specimens; Lee Weigt, Ken Shallop, Ken Wurdack, Jeff Bates and other researchers and staff at the Smithsonian Institution Laboratory of Analytical Biology for help and training in the molecular techniques. Many curators, collection managers and other biologists worldwide have assisted us with loans and fieldwork: Michael Akam, Ray Symonds and Janet Moore (University Museum of Zoology, Cambridge, UK), Ray Gibson (Liverpool, UK), Martin Thiel (Universidad Católica del Norte, Coquimbo, Chile), Helmut Sattman (Natural History Museum, Vienna, Austria), Miguel Villena (National Museum of Natural History, Madrid, Spain). Special thanks are due to Michael Akam, Janet Moore and Cassandra Extavour for their hospitality and assistance during SAM's visit to the University Museum of Zoology. We thank Gabriella Frances‐Zubillaga and the colleagues at the Universidad del País Vasco (Bilbao, Spain) for their hospitality and help in making possible SAM's collecting in Spain. Fieldwork in France was assisted by Andreas Heyland and was made possible by the help of Andre Toulmond, Nicole Sanséau, Gretchen and Charley Lambert. Fieldwork in Croatia and Italy was made possible by the help of Andreas Heyland, Vivianne Solis and Nicola Bettoso. We further thank Serena Fonda Umani and the staff of the Laboratorio di Biologia Marina in Trieste, Italy for their hospitality and assistance. Fieldwork in Belize was carried out together with Megan Schwartz, Matts Envall and Barbara Littman and was assisted by Cheryl Thacker. We are grateful to Mary Rice and the staff of the Smithsonian Marine Station at Fort Pierce for their help and assistance in making fieldwork in Florida possible. Fieldwork in California was carried out together with Rebecca Kirk‐Ritger and assisted by the staff of the Kerkoff Marine Laboratory. We thank J. “Clint” Turbeville for providing specimens of Prosorhochmus americanus for molecular work. We are grateful to the two anonymous reviewers for comments on this manuscript. This project was supported by the U.S. National Science Foundation (DEB‐9712463 to Norenburg and Lipscomb). SAM was supported by the Friday Harbor Labs Postdoctoral Fellowship while preparing the manuscript for submission. We acknowledge additional material and financial support of the George Washington University, Smithsonian Institution and University of Washington's Friday Harbor Labs. This is contribution number 724 of the Smithsonian Marine Station at Fort Pierce and number 819 of the Smithsonian Caribbean Coral Reef Ecosystem program (Carrie Bow Cay, Belize).