Octocorallia (primarily soft corals and gorgonians) occur in cold-water environments as well as in tropical seas and can form a major component of reef communities. Because of their... Show more Octocorallia (primarily soft corals and gorgonians) occur in cold-water environments as well as in tropical seas and can form a major component of reef communities. Because of their abundance and three-dimensional structure octocorals are an important habitat for symbiotic species such as crustaceans, worms, fishes and molluscs. Among the latter group are snails of the family Ovulidae, obligate associates of octocorals. Ovulid snails have adapted their morphological appearance to avoid predation. They can either be perfectly camouflaged or ambiguously coloured to advertise their toxic properties. It was therefore expected that these morphological adaptations would have an evolutionary background, which would corresponds with that of their octocoral hosts. In this thesis the evolutionary history of the Ovulidae and Octocorallia are examined within and between both taxa by using a multifaceted approach, consisting of (calibrated) phylogenetic and co-evolutionary analyses, taxonomic revisions and coral bioactivity research. The results show that snails and octocorals did not coevolve, but that the evolutionary history between both groups is best described as sequential evolution in which the host affects the symbiont but not vice versa. Show less
This thesis reviews the available coral studies in the Persian Gulf at a large scale, discusses the environmental challenges for corals in the context of climate change, and expands our... Show more This thesis reviews the available coral studies in the Persian Gulf at a large scale, discusses the environmental challenges for corals in the context of climate change, and expands our knowledge of coral biodiversity and biogeography of the region, highlights the remaining gaps in our knowledge and goes on to provide recommendations for further research. This is of special importance given recent international interest in the region as a harbinger of coral adaptation to climate change as the impacts to the global environment, human society and the economy unfold. Show less
The current classification of the Nephtheidae (Cnidaria, Octocorallia) is still based on colony morphology. In this family the Indo-Pacific genera Litophyton, Nephthea, Dendronephthya and... Show moreThe current classification of the Nephtheidae (Cnidaria, Octocorallia) is still based on colony morphology. In this family the Indo-Pacific genera Litophyton, Nephthea, Dendronephthya and Stereonephthya, and the Atlantic genus Neospongodes form a complex mix of closely related, poorly described species, which cannot be recognized using only colony morphology. Attempts with the more modern approach of comparing skeleton composition (sclerites) resulted in describing the genus Chromonephthea Ofwegen, 2005, introduced for several species previously assigned to Dendronephthya, Nephthea and Stereonephthya. In Chromonephthea 53 species were included, 34 of which were new to science. However, the true generic status of the majority of the nominal nephtheid species remained unresolved. In an attempt to clarify the phylogenetic relationships fourteen specimens have been used in molecular analyses. Two clades were supported, which were related to the shape of the sclerites present in the polyp stalks. One clade contained the specimens with characters for Stereonephthya along with a Chromonephthea specimen as a sister group. The other clade had a __true__ Nephthea and Litophyton together with the specimens that could not be placed in any particular genus using the old classification criteria. The consequences of these results for nephtheid classification are discussed. Show less
