From flounders to seahorses: Evolutionary success of spiny-rayed fishes detailed

Jul 17, 2013
From flounders to seahorses: Evolutionary success of spiny-rayed fishes detailed
Credit: Patrick Lynch

(Phys.org) —Even as the dinosaurs were becoming extinct 66 million years ago, the ancient ancestor of spiny-rayed fishes flourished, eventually giving rise to tens of thousands of species that can now be found in home aquariums or on dinner plates. Using modern genetic tools and information from the fossil record, a team led by researchers at Yale University, University of Oxford, and University of California-Davis have constructed a detailed evolutionary history of the 18,000 species of spiny-rayed fishes existing today, a diverse group that includes basses, pufferfishes, and cichlids, and that comprises a large portion of the vertebrate tree of life.

The findings published the week of July 15 in the Proceedings of the National Academy of Sciences show surprisingly close between lineages of such as tunas and seahorses, and suggest some fish lineages—like cichlids, the tiny gobies, and little-studied snailfishes—are experiencing high rates of new species origination.

"In classifying fishes, scientists used to put tunas and the swordfish in the same taxonomic group or 'bucket'," said Thomas Near, associate professor of ecology and and lead author of the paper. "This new molecular work allows us to refine our buckets and shows, for instance, that swordfish are actually more closely related to flounders and other flatfishes than to tunas."

The ancestor of all spiny-rayed fishes, or acanthomorphs, arose 140 million years ago, and emerging lineages spread to almost all oceans and freshwater habits. Acanthomorphs include almost a third of all vertebrate species, and their body plans are as diverse as flatfishes, deep sea anglerfishes, and several lineages that resemble eels.

"They account for almost every fish we eat today in the United States, with the exception of anchovies, catfish, trout, herrings, and salmon," Near said.

To understand the history of the acanthomorph's evolutionary success, the team studied 10 genes with a known mutation rate in 520 different fish species and cross-checked results with fossils of known ages. In addition to discovering surprising genetic relationships, they also discovered that some families of fish—such as snailfish and cichlids—seem to have high rates of speciation, meaning the extraordinary species richness of spiny-rayed fishes continues to be generated in a wide variety of habitats.

"Their success does not seemed to be tied to a single habitat like coral reefs as some have thought, but to their versatility," Near said.

Explore further: New research reveals clock ticking for fruit flies

Related Stories

Fossil shows fish had sucker on its back

Jul 17, 2013

(Phys.org) —A 30-million-year-old fossil has revealed how remoras – also called sharksuckers – evolved the sucker that enables them to stick to other fish and 'hitch a ride'.

Mystery of the flatfish head solved

Jun 25, 2012

Those delicious flatfishes, like halibut and sole, are also evolutionary puzzles. Their profoundly asymmetrical heads have one of the most unusual body plans among all backboned animals (vertebrates) but the ...

Recommended for you

New research reveals clock ticking for fruit flies

1 hour ago

The army of pesky Queensland fruit flies that annually inflict many millions of dollars-worth of damage on the nation's horticultural industry may be about to see their numbers take a significant dive thanks ...

The ABC's of animal speech: Not so random after all

3 hours ago

The calls of many animals, from whales to wolves, might contain more language-like structure than previously thought, according to study that raises new questions about the evolutionary origins of human language.

User comments : 0