Phylogeny of the family Podoctidae (Arachnida: Opiliones): evolution of sexual dimorphism and paternal care

• Grant number: 24/02905-5
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: April 01, 2025
• End date: March 31, 2028
• Field of knowledge: Biological Sciences - Zoology - Taxonomy of Recent Groups
• Principal Investigator: Glauco Machado
• Grantee: Miguel Angel Medrano Leal
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Podoctidae, the most diverse family in the superfamily Epedanoidea, is a Palaeotropical harvestmen group currently comprising 58 genera and 131 species. They exhibit high diversity in India, Sri Lanka, Southeast Asia, and the Philippines. Interestingly, the family contains the majority of endangered species within the order Opiliones, likely a consequence of high micro-endemism on small islands. The taxonomic history of podoctids is brief, and the definition of species and supraspecific taxa is poorly known. This taxonomic impediment has hindered significant progress, and even with the utilization of molecular data, where the only published phylogenetic analysis did not markedly improved our understanding of the family's systematics. Moreover, the proposed parental care by males carrying eggs on their hind legs has recently been questioned, with molecular data suggesting that these eggs belonged to spiders rather than the examined harvestmen. However, strong criticism to his result has emerged, keeping the debate open. This project aims to reconstruct the evolutionary history of podoctids by inferring a broader phylogeny of podoctids based on sequence capture phylogenomics (e.g. Ultraconserved Elements, UCEs) and morphological data. The project will explore diversity patterns within the family and evolution of sexually dimorphic characters. Additionally, behavioral observations and molecular paternity analyses will be carried out to determine the origin of the eggs carried by males. Through these efforts, the project will contribute to the knowledge of biodiversity in regions globally recognized as hotspots and provide valuable support for the conservation of threatened species occurring in locations facing rapid loss of natural habitats.