Occurrence of the Phoronid Phoronopsis albomaculata in Cocos Island, Costa Rica

The phoronid Phoronopsis albomaculata was collected in subtidal (28– 35 m) sandy sediments in Bahı́a Chatham during a benthic survey designed to describe the biota of Cocos Island (Isla del Coco), Costa Rica, a national park and Human Heritage Site. Occurrence of this widespread species in Cocos Island is the first report of a phoronid for Costa Rican waters and is the second locality recorded for the eastern Pacific. Taxonomically significant characters (presence of an epidermal collar, extent of coiling of lophophore and nephridia) are discussed. Comparisons are made between depth and abundance of this species from Cocos Island and results of previous studies. The phoronids are a small group of lophophorate marine invertebrates given phylumlevel status by some although others regard them, along with the Brachiopoda and Bryozoa, as a class within the phylum Lophophorata (Emig 1979, 2009). Regardless of their higher-level classification, the phoronids are subdivided into two genera, Phoronis and Phoronopsis, with only 10 species described worldwide. These vermiform benthic organisms are tube-dwelling suspension feeders with a U-shaped digestive tract and a tentacled lophophore. Food particles such as phytoplankton and detritus are captured on the ciliated tentacles of the lophophore and transported to the mouth at the base of the lophophore. The anus is found dorsal to the mouth outside the lophophore at the tip of an anal papilla that usually also bears a pair of nephridial openings. Emig (1971, 1979, 1982a) reviewed the 10 known species of Phoronida and later (Emig 2009) reviewed the five species known to occur along the Pacific and Caribbean coasts of Central America. At the time of the latest review (Emig 2009) no phoronids had been reported from Costa Rican waters although it is likely that several species do occur but have not yet been reported due to low sampling effort. Recently, as part of a long-term effort to describe the biota of Cocos Island by the Centro de Investigación en Ciencias del Mar y Limnologı́a (CIMAR) of the Universidad de Costa Rica, specimens of Phoronopsis albomaculata Gilchrist, 1907, have been obtained and are discussed here. materials and methods Benthic infaunal collection was carried out during the CIMAR-COCO-I (9–20 October 2007) and CIMAR-COCO-II (2–13 April 2008) expeditions to Isla del Coco (Cocos Island), Pacific Costa Rica, 5 30 0 57 00 N, 87 03 0 40 00 W (Cortés 2008). The main objective was to study the diversity of marine organPacific Science (2010), vol. 64, no. 3:459–462 doi: 10.2984/64.3.459 : 2010 by University of Hawai‘i Press All rights reserved 1 This paper is part of the Centro de Investigación en Ciencias del Mar y Limnologı́a-Universidad de Costa Rica (CIMAR-UCR) project ‘‘Conocimiento y gestión de medios marinos y coralinos del Área de Conservación Marina Isla del Coco,’’ No. 808-A7-520 of Fundación de la Universidad de Costa Rica para la Investigación (FUNDEVI-UCR), and was funded by the French Fund for the World Environment (FFEM). Manuscript accepted 14 September 2009. 2 Department of Invertebrates, Museum of Comparative Zoology, Harvard University, 26 Oxford Street, Cambridge, Massachusetts 02138. 3 Centro de Investigación en Ciencias del Mar y Limnologı́a (CIMAR), Universidad de Costa Rica, San Pedro, 11501-2060 San José, Costa Rica. 4 Programa de Doctorado del Departamento de Ecologı́a y Biologı́a Animal, Facultad de Ciencias del Mar, Universidad de Vigo, Spain. 5 Escuela de Biologı́a, Universidad de Costa Rica. 6 Corresponding author (e-mail: jeffro.alejandro@