Historical Biogeography of Spiny Lobsters in the Genus Panulirus (Achelata: Palinuridae)

Aim Panulirus is the spiny lobster genus with the most living species, containing 22 recognised species split into two lineages distinguished by habitat preference. Diversification has been proposed to occur due to geographic events affecting the distribution of adults and the dispersal potential of long‐lived larvae by oceanic currents. Previously, the most thorough biogeographic inference for Panulirus described diversification influenced by vicariance events resulting from plate tectonics and oceanic currents from the Palaeocene to the Pleistocene. We present updated comprehensive phylogenetic hypotheses and historical biogeography reconstruction models for the spiny lobster genus Panulirus . Location Tropical and subtropical oceanic regions, especially the Indo‐West Pacific. Taxon The spiny lobster genus Panulirus (White 1847); infraorder Achelata, fam. Palinuridae. Methods We assembled a dataset of 250 sequences representing mitochondrial (COI and 16S) and nuclear (18S, 28S and H3) gene fragments for 59 members of the Achelata, including 22 living Panulirus species and 4 subspecies. Phylogenetic relationships were reconstructed from all concatenated gene fragments and time‐calibrated using fossils. Ancestral distributions across deep time were modelled, and informed historical biogeographic inferences were made. Results The Achelata and the Palinuridae emerged in the Tethys during the Triassic epoch (~231 and ~225 Mya, accordingly). After the ancestor of Panulirus diverged during the late Jurassic (~164 Mya), Panulirus L1 and L2 originated in the Western and Indo‐Pacific during the early (~135 Mya) and late (~87 Mya) Cretaceous, respectively. The genus Panulirus experienced the most diversification during the Eocene (~52 Mya), then continued to diversify until the Pliocene (~3 Mya), with the greatest concentration of ancestral species inhabiting the Indo‐West Pacific. Main Conclusions Divergence within the Achelata has been primarily driven by shifts in plate tectonics and oceanic current patterns. Dispersal and, secondarily, vicariance were supported as the main driving forces behind Panulirus diversification. Geographic events likely significantly impacted the dispersal and settlement of long‐lived phyllosoma larvae, thus altering gene flow patterns.