Phylogeny and tempo of diversification in the superradiation of spiny-rayed fishes

Abstract

Spiny-rayed fishes, or acanthomorphs, comprise nearly one-third of all living vertebrates. Despite their dominant role in aquatic ecosystems, the evolutionary history and tempo of acanthomorph diversification is poorly understood. We investigate the pattern of lineage diversification in acanthomorphs by using a well-resolved time-calibrated phylogeny inferred from a nuclear gene supermatrix that includes 520 acanthomorph species and 37 fossil age constraints. This phylogeny provides resolution for what has been classically referred to as the "bush at the top" of the teleost tree, and indicates acanthomorphs originated in the Early Cretaceous. Paleontological evidence suggests acanthomorphs exhibit a pulse of morphological diversification following the end Cretaceous mass extinction; however, the role of this event on the accumulation of living acanthomorph diversity remains unclear. Lineage diversification rates through time exhibit no shifts associated with the end Cretaceous mass extinction, but there is a global decrease in lineage diversification rates 50 Ma that occurs during a period when morphological disparity among fossil acanthomorphs increases sharply. Analysis of clade-specific shifts in diversification rates reveal that the hyperdiversity of living acanthomorphs is highlighted by several rapidly radiating lineages including tunas, gobies, blennies, snailfishes, and Afro-American cichlids. These lineages with high diversification rates are not associated with a single habitat type, such as coral reefs, indicating there is no single explanation for the success of acanthomorphs, as exceptional bouts of diversification have occurred across a wide array of marine and freshwater habitats.

Ancestral duplications and highly dynamic opsin gene evolution in percomorph fishes

“…Using a phylogenetic representative sample of 97 fish species (Table S1) covering most of the currently recognized neoteleost lineages [Neoteleostei (19)], we first show that a duplication of SWS2 into SWS2A and SWS2B occurred around the appearance of the first neoteleosts 190-170 Mya (26,27), thereby shifting the previously described acanthomorph-specific origin of this duplication deeper into the teleost phylogeny (18,21) (Fig. 1).…”

“…Unlike in tetrapods, where this basic opsin setup remained relatively constant, teleost opsins have duplicated extensively, leading to an astonishing richness of opsin genes (18). Opsins are particularly diverse in spiny-rayed fishes [Acanthomorpha (18)]-with >18,000 species, it is the most species-rich taxon of vertebrates that also includes the highly diverse percomorphs (19).…”

How predation shaped fish: the impact of fin spines on body form evolution across teleosts

“…To take into account the possibility of families being non-monophyletic, we randomly sampled an exemplar species per family 100 times and ran all analyses across the resulting topologies. Traditionally built but less comprehensive phylogenies of teleost clades show some different family-level relationships [51,52]; to see if this was likely to change our results we also ran additional analyses on an alternative, albeit smaller topology [51] (see electronic supplementary material, table S2).…”

A new Oligocene relative of the Caproidae (Teleostei: Acanthopterygii) from the Outer Carpathians, Poland

“…A suprising difference is that Antigonia does not form a clade with Capros but, rather, is the sister-group to Zorzinichthys, Parahollardia, and zeiforms. Osteological studies (Rosen 1984, Tyler et al 2003, Tyler & Santini 2005 and some molecular analyses recognized Capros and Antigonia as sister groups, while other molecular analyses placed them far from each other (Li et al 2009, Near et al 2013. A zeiform clade (Protozeus, Cyttus, Oreosoma) is supported by eight synapomorphies.…”

“…Some molecular analyses, based on full mitochondrial genomes, or a combination of mitochondrial and nuclear genes, place zeiforms as the sistergroup to gadiforms as one of the most basal lineages of Acanthomorpha, while tetraodontiforms and caproids are fairly closely related to one another, or are even sistergroups within Percomorpha (Chen et al 2003, Miya et al 2003, Dettaï & Lecointre 2008, Li et al 2009, Grande et al 2013, Near et al 2013. Position of caproids within Percomorpha is still not clear in such analyses, neither in the morphological analyses (see Wiley & Johnson 2010).…”