Molecular phylogenetics reveals the evolutionary history of marine fishes (Actinopterygii) endemic to the subtropical islands of the Southwest Pacific

The origins of marine fishes endemic to subtropical islands of the Southwest Pacific

“…Our analyses were based on the time‐calibrated trees and sequence data presented in Samayoa et al (2022). Briefly, the authors defined marine fish taxa as endemic to the Southwest Pacific when they occurred in at least one of the subtropical islands of Lord Howe, Norfolk and Rangitāhua, without extending beyond mainland Aotearoa (New Zealand), New Caledonia and the East coast of Australia (Figure 1).…”

“…In total, 13 independent Bayesian time‐calibrated phylogenies were inferred across the tip of the actinopterygian tree using fossil calibrations (Bouckaert et al, 2019). In our study, we selected 17 of the 21 genera analysed in Samayoa et al (2022) to examine the historical biogeography of endemic taxa from the Southwest Pacific across the best‐sampled trees. We excluded two monotypic genera and two genera that only included around 50% of known congeners to minimize any inaccuracies introduced by missing taxa (Hodge & Bellwood, 2016).…”

“…Location of the Southwest Pacific (blue square), including East Australia, New Caledonia and Aotearoa New Zealand, as well as three subtropical oceanic islands (red crosses: Lord Howe—LH; Norfolk Island—N and Rangitāhua—R), following Samayoa et al (2022). Map projection: Mollweide.…”

“…For Nemadactylus , taxa are found in cold southern waters of the Atlantic and the Pacific, for which reason we allowed the connection between the Atlantic and temperate Australia to simulate the connectivity of these waters along the West Wind Drift (Waters, 2008). For Girella , given that the sole Atlantic member is closely related to congeners found in the Northwest Pacific (Beldade et al, 2021; Samayoa et al, 2022), we allowed connectivity among both areas. For Upeneus , the Atlantic and the Pacific were connected through the Indian Ocean where most taxa occur.…”

“…First, we determine the prevalence of vicariance and jump‐dispersal as biogeographical processes shaping endemism patterns in the region. Given the suggested role of the oceanic islands in generating biodiversity (Samayoa et al, 2022), we hypothesized that founder‐event speciation models would be favoured. Second, we examine the influence of geographical proximity of source locations and their climate on dispersal probabilities.…”