Between sand and salt: phylogeography of the Australian salt lake wolf spider Lycosa salifodina (Araneae: Lycosidae)

Abstract

Australian salt lakes are distinctive ecosystems that support specialized biota and provide opportunities to study evolutionary and biogeographic processes. Many salt lakes occur along ancient river channels (palaeodrainage systems), which form natural replicates for testing hypotheses of vicariance and dispersal among isolated habitats. We examined the phylogeography and genetic structure of the Australian wolf spider Lycosa salifodina McKay, 1976, a salt lake habitat specialist widespread across south-western Australia. We tested the hypothesis that genetic structure in L. salifodina primarily reflects long-term isolation among palaeodrainage systems, with reduced population structuring in more frequently inundated and interconnected lakes. Phylogenetic analyses of mitochondrial CO1 sequences from 26 specimens (collected 2023–2024) recovered three major clades (A–C) largely corresponding to discrete palaeodrainage systems. Clade A, occurring in north-western palaeodrainages (e.g. Lakes Barlee, Giles and Moore), showed >5% divergence from other clades. Clade B comprised populations from north-eastern inland palaeodrainages (Lakes Raeside, Ballard, Rebecca and Marmion), while Clade C included southern, near-coastal populations spanning multiple palaeodrainage systems. Genetic divergence within clades was low (1–3% pairwise divergence), with no haplotype sharing among localities. Molecular dating suggests that the L. salifodina complex originated approximately 15 million years ago during the Miocene, with divergence among the three major clades occurring within the last 4 million years, coinciding with increased salinization of palaeodrainage systems. Stronger genetic isolation in northern inland populations and weaker structuring in southern coastal lakes support the hypothesis that palaeodrainage history and hydrological connectivity jointly shape diversification in this species.

Heidenreich, T. O., Framenau, V. W., Do Prado, A. W., & Harms, D. (2026). Between sand and salt: Phylogeography of the Australian salt lake wolf spider Lycosa salifodina (Araneae: Lycosidae). Zoologischer Anzeiger. https://doi.org/10.1016/j.jcz.2026.07.007