Prolonged morphological expansion of spiny-rayed fishes following the end-Cretaceous

Abstract

Spiny-rayed fishes (Acanthomorpha) dominate modern marine habitats and comprise more than a quarter of all living vertebrate species1-3. It is believed that this dominance resulted from explosive lineage and phenotypic diversification coincident with the Cretaceous-Paleogene (K-Pg) mass-extinction event4. It remains unclear, however, if living acanthomorph diversity is the result of a punctuated burst or gradual accumulation of diversity following the K-Pg. We assess these hypotheses with a time-calibrated phylogeny inferred using ultraconserved elements from a sampling 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 diversity 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 diversification were decoupled from periods of high phenotypic disparity.

The rise of biting during the Cenozoic fueled reef fish body shape diversification

“…Thus, ecological shifts toward grazing-resilient structures in response to invertebrate grazers may have made reef conditions increasingly favorable for biters and able to support larger communities of high-efficiency attached prey feeders ( 55 ), such that when fishes began to use biting and evolved functional features adapted for benthic feeding, like shortened jaws and flexible teeth ( 28 , 38 , 39 , 59 ), they were extremely successful and were able to diversify within this broad adaptive zone. This pattern could contribute to the previously observed increase in morphological and species diversification of acanthomorph fishes in the Early to Mid-Cenozoic ( 60 ). A similar ecological mechanism may explain the dramatic rise of dedicated biting in the last 30 My ( Fig.…”

Chromosome-Level Genome Assembly of the Bioluminescent Cardinalfish Siphamia tubifer: An Emerging Model for Symbiosis Research

“…2 a ). The maximum likelihood phylogeny based on the whole mitochondrial genome (excluding the CR) confirms that S. tubifer is divergent from the rest of the Apogonidae family but is a member of the Apogonoidei clade, which is sister to the Gobioidei ( Ghezelayagh et al 2021 ) ( fig. 2 c ; fig.…”

Reproductive innovation enabled radiation in the deep sea during an ecological crisis

“…Phylogenetic relationships among the major lineages of anglerfishes have evaded resolution even in the era of widespread genome sequencing 13,[27][28][29][30][31] . We inferred a timecalibrated phylogenomic tree of anglerfishes using a dataset of 975 ultraconserved element (UCE) loci sequenced for 244 individuals, including 222 specimens of anglerfishes (Lophioidei) and 20 species of their sister lineage, the pufferfishes, ocean sunfishes, and triggerfishes (Tetraodontoidei).…”