Mitonuclear discordance, the incongruence between mitochondrial DNA (mtDNA) and nuclear DNA (nuDNA), is a well‐documented phenomenon with various potential explanations. One emerging hypothesis, ghost introgression, refers to the genetic contribution of an ancient, extinct or unsampled lineage and can now be tested using modern genomic data and demographic models. In this study, we investigated the evolutionary history of the...

Allopatric speciation is a widely accepted hypothesis for species distributed across geographic barriers. Meanwhile, niche conservatism, the tendency of species to retain their ancestral ecological traits, helps reinforce genetic differentiation by stabilising species distributions over time and reducing the role of competition in shaping range boundaries. In contrast, hybridisation can occur at the edges of distribution after...

Specialization in narrow ecological niches may not only help species to survive in competitive or unique environments but also contribute to their extermination over evolutionary time. Although the “evolutionary dead end” hypothesis has long been debated, empirical evidence from species with detailed information on niche specialization and evolutionary history remains rare. Here we use a group of four closely related Cnemaspis...