Giomar Helena Borrero-Pérez

Southern Caribbean azooxanthellate coral communities off Colombia

As a result of the explorations carried out by the Colombian Marine and Coastal Research Institute (INVEMAR) between 1998–2002 along the Colombian Caribbean continental shelf and upper slope, the occurrence of azooxanthellate coral banks was suspected at three sites (from the northern to southern Colombian Caribbean coast): off La Guajira Peninsula, at a water depth of 70 m; off Santa Marta, at 200 m, and nearby the San Bernardo Archipelago, at 150 m). Each site exhibited particular bottom features (relief and substrate), suggestive of reef structures. The analysis of the fauna collected by bottom trawling at these sites showed that many of the fishes, mollusks, echinoderms, crustaceans, antipatharians, soft corals and bryozoans collected are characteristic dwellers of hard substrates or reef bottoms. At the first site (Guajira) the hard coral Cladocora debilis, was the most abundant; a total of 156 species of invertebrates and fishes were identified among the material collected at this site. At the second site (Santa Marta), 13 scleractinian species were collected, but Madracis myriaster, was the dominant species; another 102 species of invertebrates and fishes were also found. At the third site (San Bernardo) 19 scleractinian species were found, M. myriaster being the dominant. A total of 135 species of invertebrates and fishes were collected at this site. It is presumed that deep-sea coral banks have developed in these three settings, since many of the collected species are known to be hard or reef bottom dwellers.

A new record of Holothuria arguinensis colonizing the Mediterranean Sea

Holothuria arguinensis is reported for the first time on the south-eastern Spanish coast. One specimen of this species was identified in El Mojon (Alicante, Spain, 37°50′54.17″N 0°45′39.90″W). This finding widens the geographical range of H. arguinensis and demonstrates that its environmental requirements are changing. Future genetic studies in this species would allow us to improve our understanding of its colonization from the Atlantic Ocean to the Mediterranean Sea.

Molecular systematics of the genus Holothuria in the Mediterranean and Northeastern Atlantic and a molecular clock for the diversification of the Holothuriidae (Echinodermata: Holothuroidea)

This work investigates the systematics of the genus Holothuria in the Mediterranean Sea and Northeastern Atlantic in the light of a wider molecular phylogenetic hypothesis of Holothuriidae, and it also provides a time-scale for the family diversification using mitochondrial markers and the molecular clock hypothesis. The subgenera Holothuria and Roweothuria are retrieved as paraphyletic. At least four separate lineages, with quite different time frameworks were identified. There are at least three species with an apparent long evolutionary history, H. forskali, H. sanctori and H. impatiens and six species belonging to Holothuria, Roweothuria and Vaneyothuria, which have diverged relatively recently.

Echinoderms of Colombia

Colombia is recognized as a megadiverse country based primarily on terrestrial biodiversity. However, it has a coastline on the Caribbean Sea and Pacific Ocean, home to many marine ecosystems, which in many cases have not been investigated. As expected, the Caribbean and Pacific coasts of Colombia exhibit different geological, oceanographic, climatic, and social characteristics. This in turn gives rise to major differences in their biota, as well as the development of marine research on each coast. For this reason, this chapter separates the information for the Caribbean and the Colombian Pacific. It uses the ecological sectors of each coast proposed by INVEMAR in 2000. There are 388 species of echinoderms known from Colombia, 264 are in the Colombian Caribbean (22 crinoids, 67 asteroids, 80 ophiuroids, 51 echinoids, 44 holothurians) and 124 are in the Colombian Pacific (34 asteroids, 30 ophiuroids, 28 echinoids and 32 holothurians). For the Colombian Caribbean Sea, although there are information about echinoderms from intertidal and shallow water ecosystems such as rocky shores, coral reefs, sandy beaches, mangrove areas, seagrass beds, and soft bottoms, currently the most complete information is from deep sea ecosystems; specifically from soft bottoms and deep azooxanthellate coral communities, where echinoderms appear to be one of the most diverse and abundant megafaunal group together with cnidarians, mollusks, crustaceans and fishes. For Pacific echinoderms only, shallow ecosystems are described, including cliffs and rocky shores, coral reefs, sandy beaches, mangrove areas, and submerged rocky and sandy substrates. Rocky shores and coral reefs are the richest in species. In general, research in Colombia has focused on taxonomy and some ecological aspects. It is necessary to continue with these kinds of studies and to delve into issues such as structure of assemblages of species distribution, population densities, and relate them to environmental and oceanographic conditions in the area. All this information is important as a baseline for decisions on conservation in the current context of growing interest in oil exploration in the seabed and coastal development. With regard to fisheries and conservation, unlike the Colombian Pacific where no information is available, in the Caribbean Sea there are fishery records of some species of sea cucumbers. It is necessary to begin the study population dynamics and reproductive cycles of these fishery species. Some species, such as Ophiothrix synoecina, Diadema antillarum and Oreaster reticulatus, have been included in conservation initiatives such as the red book of marine invertebrates of Colombia. There are many issues about Colombian echinoderms to investigate, especially for the Colombian Pacific, about which knowledge is still very incomplete compared to the Colombian Caribbean. Thus it is important to continue with the study of both basic and applied issues and to start taking advantage of new tools such as molecular techniques to investigate cryptic speciation, population connectivity, species adaptation and conservation biology, considering that Colombia is a country with a privileged location to answer questions about the evolution of species in the Americas and has many resources to conserve and use sustainably.