he papers in which are part of this theses describe the global diversity and conservation status of damselflies and dragonflies, contain a moleculair revision of the damselflies and discuss the... Show morehe papers in which are part of this theses describe the global diversity and conservation status of damselflies and dragonflies, contain a moleculair revision of the damselflies and discuss the biogeography of damselflies and dragonflies in the Australasian region. Show less
Forest damselflies (family Platystictidae) are widespread in southeast Asia from Sri Lanka to New Guinea, and are also known from Central America and the northern part of South America. The larvae... Show moreForest damselflies (family Platystictidae) are widespread in southeast Asia from Sri Lanka to New Guinea, and are also known from Central America and the northern part of South America. The larvae of most species live in small streams or seepages under forest canopy. Adults are found hanging from the tips of leaves or twigs along streams. The family is thought to have evolved more than 100 million years ago. Only 213 species are known worldwide, of which the author described 46 as new to science. Although most species are remarkably similar in general appearance, they show significant variation in structural details such as wing venation, pronotum, and secondary genitalia of the male. The group is ideal for biogeographical studies, since most species have small distributional ranges. A reconstruction of the phylogeny shows that several ancient lineages occur along the margin of the Indian Plate. Although Platystictidae are not known from Africa, it is hypothesized that the family evolved on that continent. The ancestors of the subfamilies Platystictinae and Sinostictinae drifted with India to Asia between 100 and 45 Ma. A scenario of the historical biogeography of the Platystictinae is described in relation to the palaeogeography of southeast Asia since the Eocene. The subfamily Palaemnematinae most likely dispersed from Africa to the New World via Europe and the ‘North Atlantic Land Bridge’. Show less
Africa has a large and almost uninterrupted land surface that is isolated from surrounding continents. In the last 20 million years Africa had a variable and increasingly dry climate. As a result... Show moreAfrica has a large and almost uninterrupted land surface that is isolated from surrounding continents. In the last 20 million years Africa had a variable and increasingly dry climate. As a result the Afrotropics have only half as many odonate species as tropical America or Asia. __Relict__ families are scarce and concentrated in five isolated, climatically stable areas: (1) the Cameroon highlands, (2) locally in East Africa, (3) the Cape region, (4) the granitic Seychelles, and especially (5) Madagascar. Most African odonate species, about two-fifths, are restricted to the Central and West African forests. The remainder is found, in three fairly equal parts, in (1) the highlands from Arabia to the Cape, (2) Madagascar and surrounding archipelagos, and (3) open habitats throughout the region. Most mainland species appear related to the relatively diverse fauna of tropical Asia, but have few relatives on Madagascar, suggesting that the modern continental fauna mostly diversified after the arrival of Asian ancestors. Being best adapted to change, Coenagrionidae and Libellulidae are the largest odonate families on Earth. Only in temperate regions, impacted strongly by the ice ages, is their dominance comparable to that in changeable Africa. The climatic influence is further seen in forest species __stranded__ in highlands by forest reduction, savanna species __trapped__ by forest expansion, and overseas colonisation of East Africa by island species. Traditional theory is that speciation took place in habitat fragments created by climatic change, especially in forest refuges, but such refuges seem to conserve old species rather than generate new ones. Abrupt habitat gradients in heterogeneous landscapes may be more important in speciation, especially close to areas where potential ancestors are conserved. The habitat mosaic on the Congo-Zambezi watershed is the best modern example of such an area. Phylogenetic research of various African plants and animals indicate that environmental and dispersal barriers are easily straddled, with savanna species radiating from a forest ancestors and vice versa. Species were eliminated with climatic change, but new ecological space was also constantly created. Such processes must also have lead to the __demise__ of most of Africa__s old odonate diversity and the __rise__ of a rich new fauna. Show less
