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Nueva Esparta, Venezuela, e-mail: Although ascidians form a conspicuous part of sessile assemblages in the Caribbean, no specialized inventories have been asciddiacea in Venezuela, except for a list of 15 species reported from Margarita Island La Restinga National park was surveyed and we found 29 species belonging to 19 genera and 10 families. The ascidiaca abundant colonial species were Clavelina oblongaAplidium accarensePolyclinum constellatumDistaplia bermudensisSymplegma rubraS.
Among the solitary ascidians Phallusia nigra, Ascidia curvata, Microcosmus exasperatus, Styela canopus, Styela sp.
The ascidian diversity in this lagoon is one of the highest for similar habitats in the Caribbean and seven species are new registers for Venezuela Ascidia curvata, Ecteinascidia styeloides, Aplidium accarense, Distaplia stylifera, Trididemnum orbiculatum, Symplegma rubra, and S.
Class point of concern for the conservation of la Restinga National Park is the presence of possible introduced species, and some management procedures are suggested. Urochordata, taxonomy, South Caribbean, mangrove, coastal lagoon, conservation, bioinvasion.
Ascidians are one of the most conspicuous invertebrate groups in coastal benthic assemblages. In Venezuela, however, no specialized inventories have been developed except for the list of 15 species presented by Goodbody b for Margarita Island. However, a few studies described the vlase fauna and only 15 species have been reported Ascidiacra b, Orihuela et al.
Although a few lagoons have ascidiiacea studied in the Caribbean, ascidiacwa better known usually contain between species of ascidians ToffartGoodbody Our survey increased the registers of ascidians in the mangrove complex La Restinga to at least 29 species. La Restinga is a coastal hypersaline lagoon located in the central part of Margarita Island, Venezuela.
The lagoon has an area of 30 km 2maximum depth of 6 m and is formed by a complex system of channels and ponds bordered by mangrove habitats. This survey was performed in four sites inside La Restinga: The movement of fishing and leisure boats is intense, increasing both the water hydrodynamics and the potential for species transport.
The survey was performed on 20 th and 21 st of Aprilwith ascidiacew effort of 1 hour snorkeling in each site by 14 divers. Specimens were photographed before collection for color and shape assessment of living animals. We found 29 species belonging to 19 genera and 10 families Table 1. Colonial species were abundant, usually covering solitary animals.
The most abundant species were Clavelina oblonga, Aplidium accarense, Polyclinum constellatum, Distaplia bermudensis, Symplegma rubra, S. Five species were not identified either because of the lack of enough taxonomic characters or because they did not match with ascdiacea Atlantic species: The colony contains a thin layer clas more or less dense spicules sometimes almost none on the surface and the preserved zooids are very opaque with brown pigment and orange stigmata.
The tunic is soft and extensively adheres to the zooids, at least in freshly fixed animals, which made it very difficult to pull out zooids in good condition for identification. Reproductive structures were not available for examination.
Clase ascidiacea pdf
Larvae present three adhesive papillae and four pairs of finger-like ampullae. Figure 4h presents a uniform orange colony with long linear systems. Neither gonads or larvae were available for identification. In both species the body is elongate with a variable number of gonads in each side: The structure of the gonads is also very similar with long tubular ovaries surrounded by orange elongate male follicles, not very dense or ramified, positioned vertically with only the proximal end attached to the body wall.
The follicles of Styela sp. The Entrance was the most diverse site with 28 species, and La Tortuga was the least rich with 14 species Table 1. The list of sampled species with a visual estimate of abundance is presented in Table 1 and photos of the species in the field are presented in Figures Although the survey presented here was short and covered only four sites in the lagoon, we sampled 29 species of ascidians, a relatively high richness when compared to other Caribbean lagoons with mangrove habitats: Two previous studies reported 15 species for La Restinga Goodbody b, Orihuela et al.
Among the species reported by Goodbody b and Orihuela et al. The first two are common Caribbean species and new surveys can reveal their presence in the area. Symplegma viride could be easily confounded with S. Styela plicata is an introduced species in the Atlantic Barros et al. Considering the list of known species for Venezuela, 30 species have been previously reported Table 2.
Ascidia curvata, Ecteinascidia styeloides, Aplidium accarense, Distaplia stylifera, Trididemnum orbiculatum, Symplegma rubra, and S.
Aplidium accarense, though, was first described for Ghana, Africa Millar and is also known from south Brazil where it is suspected to be introduced Rocha et al.
Molecular data would be helpful to better understand the genetic structure between the populations of Ascidkacea. Distaplia stylifera is considered by Van Name as a synonymy of D. Both are very similar indeed because the description of D. In the Caribbean it was reported from the west coast of Florida, Jamaica and Colombia Van Namebut recent studies did not list the species in Jamaica Goodbody, Guadeloupe Monniot, F c or Belize Goodbody In Bocas del Toro, Panama, it occurs in the marina of the ascdiacea, but only on artificial substrata RMR, unpublished data.
All this evidence also suggests that D. The Entrance was the richest site in species. Among the sampled species, only Didemnum duplicatum was not registered in The Entrance, but many white didemnids were observed but not collected because this was the last site visited and we were trying to not re-collect similar asciviacea.
White didemnids, though, can not be certainly identified by pictures and it is possible that we will find not only D. At La Tortuga the high salinity seems to be strongly selecting against the survival of some species and only half of the species encountered during this study was registered at La Tortuga. Polyclinum constellatum was especially abundant at this site as ball-shaped colonies filled with a gelatinous tunic with the zooids located only around the outer edge like the ones observed in Port Royal, Jamaica Goodbody Given the fact that it is a cold water species, its identification is doubtful.
Ascidians have been recognized as frequent invaders of new areas in recent years Lambertcausing major fouling problems for the bivalve aquaculture industry Carver et al. In natural environments they have the potential to displace native species causing reduction of biodiversity.
In La Restinga we detected some species that are already widespread in the Caribbean and probably represent historical introductions such as Microcosmus exasperatus and Styela canopus.
The presence of Ascidia sydneiensis was only guessed by photos and should be confirmed as well as Styela plicata. If present, these species are still not abundant and manual eradication could be tried.
If Aplidium accarense and Distaplia stylifera prove to be introduced they represent a real threat to the diversity of the region, since they grow in large, massive colonies that could smother and displace other species.
The movement of recreational and fishing boats has already been shown to be an important vector for intraregional spread of invaders both in freshwater and marine environments Johnson et al. Frequent cleaning of the hulls and anchors, and control of water discharge, oyster shells and other shellfish refuse, are important management procedures toward the prevention of species dispersal.
Furthermore, artificial substrates are also known as important habitats used by introduced species for first establishment Glasby et al. The avoidance of construction of piers or other structures inside the lagoon which would add artificial substrate for colonization of sessile animals and frequent less than two months cleaning of existing structures are other prevention measures that should be followed. Managers should also promote periodic monitoring to increase the chances of early detection and possible eradication of introduced species.
Old photos of mangrove roots by CL and AP showed the presence of a few species not collected in this survey, including Clavelina pictaAscidia sydneiensis and a colony with round systems which resembles Distaplia corolla.
Other cryptic species such as Corella minutaPerophora spp. It is also important to consider that the only two studied Caribbean lagoons that presented a richer community of ascidians ascidiacfa “La Restinga” are those in Belize that were studied for years and include temporary ascisiacea rare species Goodbody Thus the list here presented is far from complete and we expect to have ascidian species in La Restinga lagoon, which would make this mangrove system among the ones with the highest biodiversity in the Caribbean.
Special thanks to Prof. Monzerrat Esteves and Prof.
Clase ascidiacea pdf
We also extend our gratitude to Lic. Establecimiento, desarrollo y mantenimiento de una comunidad epibentonica tropical. Human-mediated global dispersion of Styela plicata Tunicata, Ascidiacea. Ascidians of the Bermudas.
Recent non-indigenous ascidians in the Mediterranean Sea – Semantic Scholar
Sexual differentiation and size at first maturity of the invasive mussel Perna viridis Linnaeus, Mollusca: Abbreviated larval development of Tunicotheres moseri Rathbun, Decapoda: Pinnotheridaea rare case of parental care among brachyuran crabs. Strategies to mitigate the impact of Ciona intestinalis L. In Biodiversidad en Venezuela M. Marine boating habits and the potential for spread of invasive species in the Gulf of St. Estimating the species number and cover of a mangrove-root community: Scale-dependent spatial and temporal variability in biogeography of mangrove root epibiont communities.
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Ascidians from Caribbean shallow water localities. The ascidian fauna of a Jamaican lagoon: The tropical Western Atlantic Perophoridae Ascidiacea: Diversity and distribution of ascidians Tunicata in the Pelican Cays, Belize. The ascidian fauna of Port Royal, Jamaica. Harbor and mangrove dwelling species. Diversity and distribution of ascidians Tunicata at Twin Cays, Belize.
A new species of Perophora Ascidiacea from the Western Atlantic, including observations on muscle action in related species. The tropical western Atlantic Perophoridae Ascidiacea ii. Overland dispersal of aquatic invasive species: Ecology and natural history of the protochordates.