Publication
Prolonged morphological expansion of spiny-rayed fishes following the end-Cretaceous
Publisher:
Cold Spring Harbor Laboratory
Date:
13-07-2021
DOI:
10.1101/2021.07.12.452083
Abstract: Spiny-rayed fishes (Acanthomorpha) dominate modern marine habitats and comprise more than a quarter of all living vertebrate species 1–3 . It is believed that this dominance resulted from explosive lineage and phenotypic ersification coincident with the Cretaceous-Paleogene (K-Pg) mass-extinction event 4 . It remains unclear, however, if living acanthomorph ersity is the result of a punctuated burst or gradual accumulation of ersity following the K-Pg. We assess these hypotheses with a time-calibrated phylogeny inferred using ultraconserved elements from a s ling of species that represent over 91% of all acanthomorph families, as well as an extensive body shape dataset of extant species. Our results indicate that several million years after the end-Cretaceous, acanthomorphs underwent a prolonged and significant expansion of morphological disparity primarily driven by changes in body elongation, and that acanthomorph lineages containing the bulk of the living species ersity originated throughout the Cenozoic. These acanthomorph lineages radiated into distinct regions of morphospace and retained their iconic phenotypes, including a large group of laterally compressed reef fishes, fast-swimming open-ocean predators, bottom-dwelling flatfishes, seahorses, and pufferfishes. The evolutionary success of spiny-rayed fishes is the culmination of a post K-Pg adaptive radiation in which rates of lineage ersification were decoupled from periods of high phenotypic disparity.