Biogeography of the globally distributed raft spiders (Pisauridae: Dolomedes)

Yu, Kuang-Ping (author), Kuntner, Matjaž (mentor)

The fishing spiders, genus Dolomedes, are globally distributed freshwater-associated invertebrates. Although several Dolomedes species are popular model organisms in many study fields, their biogeographic history remains largely unknown. Therefore, my dissertation aims to detect and bridge the knowledge gaps that hamper such studies and reconstruct the global biogeographic history of Dolomedes. By reviewing the vast literature, these knowledge gaps are ambiguous species boundaries, the conflicting familial affiliation, and the unknown species-level phylogeny. My dissertation develops an integrative taxonomic model to test the species boundaries among closely related Dolomedes from Madagascar and La Réunion. The model suggests that valid species with robust boundaries should be morphologically, phylogenetically, and ecological diagnosable. Through the proposed species boundaries, my dissertation gathers and delimits an extensive taxon set of 53 out of the total 105 Dolomedes species, spanning the genus range, with relevant outgroups to reconstruct a species-level UCE phylogeny. The results necessitate removal of Dolomedes and its Oceanian relatives from Pisauridae and erecting a separate family, Dolomedidae. The divergence time estimations reconstruct a late Miocene origin of Dolomedes, between 9 and 16 Ma. By integrating all the above results, my dissertation reconstructs the ancestral area of Dolomedes in the Australasian + Oriental realm. My original BioGeoBEARS pipeline, correcting physical distances among realms by historic climate data, suggests that the late Cenozoic plate tectonics and climate oscillations combined shaped the Dolomedes diversity pattern. However, the analyses detect no significant influence of morphological, behavioural, and ecological traits on the biogeographic history of Dolomedes. My dissertation largely closes the knowledge gaps in Dolomedes research. It provides new pipelines for testing species boundaries and for statistically testing the effects of climate change in historical biogeographic studies. The fact that Dolomedes is sensitive to historical climate oscillation also sheds light on understanding how global changes will impact freshwater-associated invertebrates and their habitats in the future.

• Language: Slovenian
• Keywords: Biogeography, taxonomy, systematics, phylogenetics, Dolomedidae
• Work type: Doctoral dissertation
• Typology: 2.08 - Doctoral Dissertation
• Organization: BF - Biotechnical Faculty
• Publisher: [K.-P. Yu]
• Year: 2025
• PID: 20.500.12556/RUL-176721
• UDC: 574.9:595.441(043.3)
• COBISS.SI-ID: 261110019
• Publication date in RUL: 10.12.2025

Secondary language

• Language: English
• Title: Biogeografija globalno razširjenih pajkov splavarjev (Pisauridae: Dolomedes)

Abstract

Pajki splavarji (rod Dolomedes) so globalno razširjeni nevretenčarji, vezani na sladkovodne habitate. Kljub temu, da so splavarji priljubljen modelni organizem številnih področij biologije, ostaja njihova biogeografska zgodovina neznana. Cilj moje disertacije je zapolniti vrzeli v znanju o pajkih splavarjih, ki omejujejo tovrstne študije, in nato prvič rekonstruirati njihovo biogeografsko zgodovino. Najprej predlagam integrativen taksonomski model za razmejevanje med tesno sorodnimi vrstami pajkov splavarjev z Madagaskarja in Réuniona. Po tem modelu mora biti vsaka veljavna, robustno razmejena vrsta morfološko, filogenetsko in ekološko opredeljiva. Z upoštevanjem predlaganih načel razmejitve vrst v disertaciji zberem in razmejim 53 od skupno 105 vrst pajkov splavarjev s celotnega območja rodu, ter jih, z ustreznimi zunanjimi skupinami, uporabim za rekonstrukcijo vrstne filogenije z genetskimi podatki UCE. Na podlagi rezultatov rod Dolomedes in sorodne rodove iz Oceanije izvzamem iz družine Pisauridae in jih uvrstim v novo taksonomsko družino, Dolomedidae. Časovne ocene evolucije rodu Dolomedes kažejo na izvor v poznem miocenu, pred 9 do 16 milijoni let. Z integracijo vseh zgornjih rezultatov kot izvorno geografsko območje rodu Dolomedes rekonstruiram avstralazijsko in orientalsko biogeografsko regijo. Moj izvirni protokol za analize biogeografske zgodovine z BioGeoBEARS, ki pri ocenah zgodovinskih fizičnih razdalj med biogeografskimi regijami upošteva zgodovinske podnebne podatke, kaže, da sta biološko raznolikost pajkov splavarjev oblikovala predvsem tektonika plošč v poznem kenozoiku ter podnebna nihanja. Analize po drugi strani zavračajo pomemben vpliv morfoloških, vedenjskih in ekoloških lastnosti samih organizmov na njihovo biogeografsko zgodovino. Moja disertacija tako v veliki meri zapolnjuje identificirane vrzeli v znanju o pajkih splavarjih ter vpeljuje nove protokole za vrstne razmejitve in testiranje učinkov podnebnih sprememb na biogeografsko zgodovino organizmov. Moja ugotovitev, da so na razširjenost pajkov splavarjev pomembno vplivala pretekla podnebna nihanja, pa pripomore k razumevanju vpliva prihodnjih globalnih sprememb na sladkovodne nevretenčarje in njihove habitate.

• Keywords: Biogeografija, taksonomija, sistematika, filogenetika, Dolomedidae