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The Arachnida subfamily Gasteracanthinae, commonly known as thorn or kite spiders due to their prominent abdominal spines, is mainly Pan-Tropical in distribution. Little has been published about the relationships and classification of the genera and there is still considerable taxonomic confusion about the status of some of the species in this subfamily; in particular, within the biggest genus: Gasteracantha Sundevall, 1833. This thesis represents the largest work on Gasteracantha since the studies by Dahl (1914) and Emerit (1974). By using both molecular and morphological cladistic analyses, the most comprehensive phylogeny to date of Gasteracantha, and the related genera, is inferred. By supplementing specimens from worldwide institutional collections this thesis highlights the need for both molecular and morphological data to classify these species’ relationships and why a taxonomic knowledge of the genera is critical for understanding and interpreting these relationships. Additionally, a geometric morphometric analysis is conducted to quantify and examine the evolution of the abdominal shapes of taxa within the subfamily. With a phylogeny constructed, a biogeographical distribution analysis is conducted. This is followed by an analysis of the extreme sexual size dimorphism (eSSD) between Gasteracanthinae males and females, along with an examination of the evolution of several sexually dimorphic characters. Finally, taxonomic changes are proposed, suggestions around improving molecular and morphological work along with future areas of ecological study are made, and a novel approach to gathering images for future morphometric analysis is trialled. This thesis provides a resource that will help arachnologists worldwide on the future understanding of Gasteracantha and the rest of the subfamily taxa. |
