Caribbean Journal of Science, Vol. 41, No. 3, 600-612, 2005 Copyright 2005 College of Arts and Sciences University of Puerto Rico, Mayagu¨ez Ascidians from Bocas del Toro, Panama. I. Biodiversity. ROSANA M. ROCHA*, SUZANA B. FARIA AND TATIANE R. MORENO Universidade Federal do Paraná, Departamento de Zoologia, CP 19020, 81.531-980, Curitiba, Paraná, Brazil Corresponding author: *[email protected] ABSTRACT.—An intensive survey of ascidian species was carried out in August 2003, in different environ- ments of the Bocas del Toro region, northwestern Panama. Most samples are from shallow waters (< 3 m) in coral reefs, among mangrove roots and in Thallasia testudines banks. Of the 58 species found, 14 are new species. Of the 26 sampling sites, the most diverse were Crawl Key Canal (9°15.050’N, 82°07.631’W), Solarte ,Island (9°17.929’N, 82°11.672’W), Wild Cane Key (9° 20؅40؅N, 82°10؅20؅W), Isla Pastores (9°14.332’N W), the bay behind the STRI Lab (9°21؅4.3؅ N, 82°15’25.6؅ W), and the entrance of Bocatorito Bay’82°19.968 (9°13.375’N, 82°12.555’W). Ascidians have been studied and reported from 31 locations within the Caribbean, and 139 species have been reported. This count will increase with the description of the 14 new species, and Bocas del Toro may be considered a region of high ascidian diversity since > 40% of the total known Caribbean ascidian fauna occurs there. KEYWORDS.—Ascidian taxonomy, Caribbean, checklist INTRODUCTION found and discuss the relationship of this fauna with that of other Caribbean loca- tions. Warm Caribbean waters contain a wide variety of marine environments including different types of mangroves, shallow la- MATERIALS AND METHODS goons, open sea, shallow and deep coral reefs and rocky shores distributed among the islands and coasts of Central and South In the western Caribbean, the Bocas del America. Ascidians form a diverse yet Toro archipelago, on the northwestern poorly studied group in these Caribbean shore of Panama, is comprised of more waters. The most recent listing of ascidian than 68 islands and numerous mangrove species of the Caribbean was based on the keys. Ascidians were collected in this re- following studies: Plough and Jones (1939), gion between 03 and 12 August 2003. Habi- Van Name (1921, 1924, 1930, 1945), Millar tats surveyed included mangrove roots, (1962), Van der Sloot (1969), Millar and shallow coral reefs or coral formations on Goodbody (1974), Lafargue and Duclaux sandy substrates, and very shallow sea- (1979), Monniot, C. (1983a, b, c), Monniot grass meadows of Thalassia testudinum on and Monniot (1984), Monniot, F. (1983a, b, several of the islands of the archipelago c, 1984), Goodbody (1984a, 1984b,1993, (Fig.1, see list of stations in appendix). Most 1995, 1996, 2000, 2003), Goodbody and Cole of the locations surveyed were very shal- (1987) and Hernandez-Zanuy (1990). low (< 3 m) and sampled while snorkeling, In August 2003, the Smithsonian Tropical while others were sampled in deeper wa- Research Institute hosted a workshop to ters using SCUBA equipment. Animals study the Bocas del Toro region, western were collected with their substrate (usually Panama. This region has a surprisingly rich bivalve shells on mangrove roots and small ascidian fauna and several new species pieces of dead coral on coral reefs) to insure were discovered, which will be described better anesthesia. Upon collection, samples elsewhere. Here we report the species were relaxed with menthol crystals after 600 ASCIDIAN BIODIVERSITY 601 FIG. 1. Bocas del Toro region showing diving sites (1-26). which they were fixed and preserved in same effort but each location was surveyed 10% seawater formalin. for a minimum of one hour and most sam- Most species were photographed prior to pling locations had few species (1-4). A sampling with a Canon Powershot 45 digi- quadratic regression of the species accumu- tal camera with underwater housing (See lation curve, based on the number of sites Photographic Identification Guide in this sampled, resulted in a significant model (R2 issue). = 0.97, p < 0.05). This model predicts that with 26 sites the curve reaches its asymp- RESULTS tote, and suggests that of the sites sampled, the ascidian community comprises ap- Forty-four known species and another 14 proximately 58 species (Fig. 2). new species were found during the survey. The most species-rich genera were Pyura Locations were not all surveyed with the (7 species) and Ascidia (6 species, Table 1). 602 R. M. ROCHA ET AL. depth, cover of algae and other inverte- brates. DISCUSSION At least for shallow-water ascidian com- munities in both mangroves and coral en- FIG. 2. The cumulative number of species across vironments, this survey found more species diving sites. The number of each site according to in Bocas than has been recorded in any Table 1 and Fig. 1. other site in the Caribbean other than Guadeloupe. Some identifications in Table 1 are tentative because SEM photographs of The most species-rich site was Crawl Key the spicules are not yet available and these Canal (18 species, 9°15.050’N, 82°07.631’W) are important for species’ identification. between Bastimentos and Popa islands We also believe that collecting in deeper (Table 1). This channel is subject to tidal environments will further increase the currents and links the more protected bay number of ascidians in the area, e.g., with the open sea. Here, sampling took Clavelina sp. and Ecteinascidia turbinata were place on the coral reef that extends over a only found on deeper sites. The didemnids large part of the canal, including shallow to also need further study in Bocas del Toro deep locations. The second richest site, with since most colonies did not contain mature 14 species, was Solarte Island (9°17.929’N, gonads or larvae needed for identification. 82°11.672’W), a well conserved mangrove A comprehensive literature survey of the site situated inside a Conservation Unit. last 50 years showed that ascidians have Other rich sites were Wild Cane Key been recorded from 31 locations in the Car- (9°20Ј40ЈN, 82°10Ј 20ЈW, 10 species), Isla ibbean and Bermuda (Table 2, we included Pastores (9°14.332’N, 82°19.968’W, 9 spe- Bermuda since that ascidian fauna is simi- cies), the bay at the STRI Lab (9°21Ј 4.3Ј N, lar to that of the Caribbean). Most of the 82°15Ј 25.6Ј W, 10 species), and the entrance localities were not intensively surveyed of Bocatorito Bay (9°13.375’N, 82°12.555’W, and very few ascidians are known from 10 species). The most commonly found spe- them. A hundred thirty-eight species are cies were Microcosmus exasperatus (found in reported, which is a low figure compared 8 dive sites), Eudistoma sp., Rhopalaea ab- with the survey of the Iberic Mediterranean dominalis and Phallusia nigra (in 5 dive sites, with 101 species (Ramos-Esplá 1988), or the Table 1). monographs by Kott from Australia with Some species were exclusively found hundreds of species (Kott 1985, 1990, 1992, on mangroves, on corals or on Thalassia 2001). leaves (Table 1), suggesting a relationship In spite of the statement by Goodbody between diversity of environments and (1984) that “the ascidian fauna of the Car- high species diversity. Even the same type ibbean is well known” it appears that of environment was not uniform in the many new species of Caribbean ascidians whole area. Coral reefs, for instance, at are still to be described when more detailed times were comprised of mostly Porites and sampling is performed in different islands. other times Millepora or Acropora. Coral It emerges that the most diverse locations reefs in different locations, such as inside are Guadeloupe, Belize, Jamaica and Ber- the bay in very protected areas (Pastores muda which were surveyed more than island) or in channels close to the open sea once and/or by specialists using diving to (Crawl Key Canal), had very different as- collect animals (Van Name 1945; Monniot cidian communities. This was also true for C. 1972, 1983a, b, c; Monniot F. 1972, 1983a, b, mangrove communities and was appar- c, 1984; Monniot and Monniot 1984, Good- ently influenced by the age of the roots, body 2000, 2003). Most of the surveys made location relative to water currents, water before these depended on low tide or were TABLE 1. Distribution of ascidian species at the diving sites surveyed in Bocas del Toro, Panamá (for a description of the sites see Collin this issue and Fig. 1). Diving site number # § 1 2 3 4 5 6 7 8 91011121314151617181920212223242526 Number of species 3 6 10 0 0 2 18 2 3 54234400914010051051 APLOUSOBRANCHIA Polyclinidae Polyclinum sp. M 1 X Euherdmania sp. 1 C 1 X Euherdmania sp. 2 C 1 X Didemnidae Didemnum conchyliatum ? (Sluiter, 1898) M 1 X D. granulatum ? Tokioka, 1954 C,T 3 X X X ASCIDIAN BIODIVERSITY 603 D. ligulum ? Monniot, 1983a C 1 X D. psammathodes (Sluiter, 1895) M 1 X D. speciosum ? (Herdman, 1886) C 1 X Trididemnum orbiculatum (Van Name, 1902) M 1 X T. savignyi (Herdman, 1886) C 1 X T. maragogi Rocha, 2002 T 1 X Lissoclinum verrilli (Van Name, 1902) C 1 X Diplosoma listerianum (Milne-Edwards, 1841) C 3 X X X Clavelinidae Clavelina sp. C 2 X X Holozoidae Distaplia bermudensis Van Name, 1902 1 X D. corolla Monniot, 1974 C 1 X Polycitoridae Cystodytes dellechiajei (Della Valle, 1877) C 3 X X X Cystodytes sp. 1 C 1 X Cystodytes cf. roseolus C1 X Eudistoma carolinense Van Name, 1945 C 2 X X E.