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 species 1-3 . It is believed that this dominance resulted from explosive lineage and phenotypic diversification coincident with the Cretaceous-Paleogene (K-Pg) mass-extinction event 4 . 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. MainThe Cretaceous-Paleogene (K-Pg) mass extinction fundamentally affected the evolutionary trajectory of terrestrial vertebrates, laying the foundation for spectacular radiations Main references1 Near, T. J. et al. Phylogeny and tempo of diversification in the superradiation of spinyrayed fishes.

A novel cis-regulatory element drives early expression of Nkx3.2 in the gnathostome primary jaw joint

“…Using a combination of mVISTA alignments and genome-wide BLASTN searches using the spotted gar and bichir as query sequences, we were able to identify JRS1 in all teleost species with the exception of most members of the clade Percomorpha: toadfish, mudskipper, soldierfish, seahorse, tilapia, amazon molly, stickleback, and pufferfish ( Figure 3 ). The only percomorph species in which we could identify an element with both sequence and syntenic homology to JRS1 was the cusk-eel, a member of the earliest branching order of percomorphs: Ophidiiformes ( Ghezelayagh et al, 2022 ; Figure 3 ). The sister order to the Percomorpha is Beryciformes, which includes the alfonsino and soldierfish.…”

“… Phylogenetic tree based on Hughes et al, 2018 and Ghezelayagh et al, 2022 . Pointed boxes represent gene orientation with gene names indicated on top.…”

“…JRS1 appears to be absent in all analysed percomorph (PERC) teleost fish with the exception of the cusk-eel, and only a small conserved sequence fragment is present in the cusk-eel, alfonsino, and soldierfish – acanthopterygian fish from the orders Ophidiiformes (O) and Beryciformes (B) that narrowly post- and pre-date the phylogenetic origin of percomorph fish, respectively ( Ghezelayagh et al, 2022 ). This suggests that while JRS1 may have been lost in the last common ancestor of all percomorphs with the exception of ophidiiforms (PERC-O), a process of loss or adaptive sequence divergence may have begun earlier, in a common ancestor of both beryciforms and percomorphs (PERC+B).…”

Alternating regimes of shallow and deep-sea diversification explain a species-richness paradox in marine fishes

“…( 113 ) to test if genome size increased with ocean depth, and the UCE phylogeny of Acanthomorpha by Ghezelayagh et al. ( 48 ).…”

A chromosome level genome assembly of longnose gar,Lepisosteus osseus

“…Teleost fishes represent over half of all living vertebrates and have successfully radiated in nearly all of the planet’s aquatic habitats (Ghezelayagh et al 2022; Near et al 2013). Teleosts are of vital ecological importance, form the basis of several multi-billion dollar industries (Lamberth & Turpie 2003; Sumaila et al 2012; Mitcheson et al 2013), and act as important model species (e.g.…”