The largest genus within the Phyllanthaceae family is a group called Phyllanthus L. Recent studies have shown, that Phyllanthus is paraphyletic with the genera Glochidion, Breynia and Synostemon... Show moreThe largest genus within the Phyllanthaceae family is a group called Phyllanthus L. Recent studies have shown, that Phyllanthus is paraphyletic with the genera Glochidion, Breynia and Synostemon nested within it. In this thesis, I study the evolution and systematics of Phyllanthus and how to solve the apparent paraphyly. First we explore past morphological subgroups to come to a subdivision, which was tested using molecular phylogenetics. Several species of Phyllanthus are also used in traditional medicine and by utilizing the living collections of the Hortus botanicus Leiden, we tested for antibacterial and antifungal bioactivity. The phylogeny resulting from this study is used to study the historical biogeography and diversification of the tribe and to propose a new classification where Phyllanthus is separated into several smaller genera. Show less
In this thesis, I targeted the orchid genus Lepanthes, one of the six genera of angiosperms that surpasses 1,000 species in the Neotropics, as a study model to investigate the evolutionary... Show moreIn this thesis, I targeted the orchid genus Lepanthes, one of the six genera of angiosperms that surpasses 1,000 species in the Neotropics, as a study model to investigate the evolutionary processes that promoted species diversifications. To investigate this, we improved the taxonomy of the group integrating a solid phylogenetic framework with morphological evolution, assessing inter-specific relationships in species complexes with hundreds of DNA markers using anchored hybrid enrichment approach, and describing new species. In addition, we addressed the pollination of Trichosalpinx through the study of floral anatomy, pollinator behavior, and floral traits. Trichosalpinx flowers are pollinated exclusively by female biting midges that are attracted by the small quantities of proteins secreted on the flowers. Finally, we inferred the biogeographical history and diversification dynamics of the two largest Neotropical orchid groups (Cymbidieae and Pleurothallidinae), using densely sampled phylogenies coupled with geological datasets and discussed the impact of biogeographical events and orogeny on the species richness of Lepanthes. Species diversification is correlated with Andean orogeny, and multiple migrations and recolonizations across the Andes indicate that mountains do not constrain orchid dispersal over long timescales. This thesis provides new insights into the complex evolution of one of the most species-rich angiosperm. Show less
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
Gall crabs (Crustacea : Cryptochiridae) are small, coral-dwelling crabs that live in obligate association with their host corals (Scleractinia), on which they rely for food and shelter. They have... Show moreGall crabs (Crustacea : Cryptochiridae) are small, coral-dwelling crabs that live in obligate association with their host corals (Scleractinia), on which they rely for food and shelter. They have been recorded from shallow and deeper waters (over 500 m), but the majority of the species live in reef corals in the photic zone. The highest number of species is recorded from the Indo-West Pacific, where coral diversity is highest. This PhD thesis deals with various aspects of their evolution and diversification; four species are described as new to science, and the host specificity, biogeography, distribution and reproductive morphology of gall crabs are studied. In addition, the close association between gall crabs and corals allowed for studies on (cryptic) speciation and possible coevolution. Results show that the observed coevolutionary events should most probably be ascribed to sequential evolution, which indicates that the phylogeny of the gall crabs has been directed by the evolution of the corals. Show less
This thesis presented eight studies in the field of systematic botany, with a focus on the molecular phylogenetics, taxonomy, and pollen morphology of the tribe Miliuseae (formerly known as the... Show moreThis thesis presented eight studies in the field of systematic botany, with a focus on the molecular phylogenetics, taxonomy, and pollen morphology of the tribe Miliuseae (formerly known as the miliusoid clade) of the pantropical flowering plant family Annonaceae. The general aims were: (1) to investigate intertribal relationships of the tribe Miliuseae, (2) to clarify generic delimitations by investigating the intergeneric relationships within the tribe Miliuseae, and (3) to understand patterns of character evolution within the tribe Miliuseae. To achieve these aims, a molecular phylogeny of a subclade of the subfamily Malmeoideae consisting of the tribes Maasieae, Malmeeae, Fenerivieae, Dendroking- stonieae (sampled for the first time), Monocarpieae, and Miliuseae was reconstructed using a much expanded taxon and chloroplast DNA marker sampling in comparison to previous studies. In addition, detailed taxonomic and/or palynological studies of the monogeneric tribes Dendrokingstonieae and Monocarpieae, and several genera in Miliuseae have been presented. The evolution of selected macromorphological and palynological characters was investigated using ancestral character-state reconstructions. Generic delimitations within Miliuseae, in light of the results of the molecular phylogenetic studies, were discussed, and two new genera, Hubera and Winitia, have been characterized based on macromorphology and pollen morphology. Show less
The northwest corner of South America harbours a region of spectacular and mysterious landscapes called Pantepui. Due to its ancient age and fragmented topography Pantepui has been assumed to be an... Show moreThe northwest corner of South America harbours a region of spectacular and mysterious landscapes called Pantepui. Due to its ancient age and fragmented topography Pantepui has been assumed to be an ideal nursery of speciation, and tepuis (table mountains) have been seen as potential inland counterparts to oceanic islands. Tepuis are often called __islands in the sky__ and their summits seem indeed ideal candidates to harbour relict species, isolated from the rest of the world for millions of years. However our knowledge about the origin and diversification of the Pantepui biota is at least as fragmentary as the tepui physiography itself. This led some authors to consider the origin of local biodiversity and endemism a still-unresolved evolutionary enigma. This work aims to (1) better understand the species diversity, the evolutionary history, the dynamics of biotic interchanges between tepui summits, and the patterns of endemism of the fauna in the Pantepui region, using morphological analyses and molecular phylogenies of six amphibian and reptile taxa; (2) provide new insights in the timing of the geomorphological evolution of the tepuis in the light of amphibian and reptile species diversification inferred from molecular phylogeny reconstructions and estimates of divergence time. Show less
