Family tree of fish yields surprises

Family tree of fish yields surprises

July 17, 2013 — The mighty tuna is more closely related to the dainty seahorse than to a marlin or sailfish. That is one of the surprises from the first comprehensive family tree, or phylogeny, of the "spiny-rayed fish," a group that includes about a third of all living vertebrate species.

---

Share This:

The work is published July 15 in the journal Proceedings of the National Academy of Sciences.

The spiny-rayed fish are an incredibly diverse group, including tuna and billfish, tiny gobies and seahorses, and oddities such as pufferfish and anglerfish. The fish occupy every aquatic environment from coral reefs and open oceans to lakes and ponds. It includes all the major commercially fished species -- all of which are threatened. But until now, no one has had any idea exactly how more than 18,000 species in 650 families are related to each other, said Peter Wainwright, professor and chair of evolution and ecology at the University of California, Davis and senior author on the paper.

"There has been a 'bush' at the top of the family tree leading to the rest of the vertebrates," Wainwright said. "Now we have this beautiful phylogeny of one-third of all vertebrates."

The study also shows that after roaring along for their first 100 million years, the pace of evolution of the spiny-rayed fish downshifted about 50 million years ago.

Some groups of fish have gone along steadily for millennia; others have gone through bursts of rapid evolution. Overall, the researchers found that the rate at which new species formed was fairly constant across the group from their origin to about 50 million years ago, then dropped about five-fold and has remained at that level since.

That might mean that these fish have essentially filled the available spaces, Wainwright said.

"It's not uncommon in evolution to see a rapid diversification followed by a slowdown, but it's never been seen on such a scale before," he said.

Wainwright's laboratory worked with the lab of Tom Near, a former postdoctoral scholar at UC Davis now at Yale University, and colleagues at the University of Tennessee, The Field Museum in Chicago, Florida Atlantic University and CUNY Staten Island to construct the family tree. Matt Friedman, a paleontologist at the University of Oxford, England, added fossils that helped set dates for branches of the tree.

The researchers looked at 10 genes in more than 500 fish species representing most of the families of spiny-rayed fish. They used the genetic data to construct a tree, grouping related families together. They also looked at the pace of evolution -- the rate at which new species formed -- in different branches, and across the group as a whole.

The spiny-rayed fish originated about 150 million years ago, separating from more primitive fish, such as lampreys, sharks and sturgeon, and from the ancestors of salmon and trout. Since then, they have spread into every aquatic habitat on Earth.

The tree shows some interesting relationships. For example, tuna are more closely related to seahorses than to swordfish or barracuda. The oddly shaped pufferfishes are related to anglerfish, the only fishes whose bodies are wider than they are deep.

Cichlids, a family that includes about 2,000 species of freshwater fish known for brooding their young in their mouths and a favorite for studies of evolution, are related to the engineer gobies, an obscure family of just two species that live on coral reefs and raise their young in a nest.

Wainwright's special interest is in the evolution of fish jaws. Fish have two sets of jawbones, an outer jaw and "pharyngeal jaws" in the throat that adapted to different functions. In some fish, the lower pharyngeal jaw is fused into a single solid bone that can be used to crush prey such as shellfish.

Biologists had assumed that this fused jaw had evolved once and then spread into different groups of fish. Instead, the new tree shows that this structure evolved at least six times in different groups of fish.

Additional collaborators on the project were: Samantha Price at UC Davis; Alex Dornburg, Ron Eytan and Kristen Kuhn at Yale University; Leo Smith at the Field Museum; Jon Moore, Florida Atlantic University; and Frank Burbrink, College of Staten Island/CUNY, Staten Island. Funding was provided by the National Science Foundation.

Welcome to SUV System Ltd!

SUV System Ltd is ISO 90012008 Certified electronics distributor with 10 years of experiences.

We have built up long term business relationship with about many companies which are stockers and authorized agents. we have a steady and reliable supply to meet customer's demands to the greatest extent .Confidently, we are able to lower your cost and support your business with our years of professional service.

SUV System Ltd is Electronic Components Distributor Supplies,Find Quality Electronic Components Supplies Products IC(Integrated Circuits),Connectors,Capacitor,Resistors,Diodes,Transistors,LED at Suvsystem.com. Sourcing Other Energy, Environment, Excess Inventory Products from Manufacturers and Suppliers at Suvsystem.com

Electronic Components distributor:http://www.suvsystem.com

Connectors Distributor:http://www.suvsystem.com/l/Connectors-1.html

IC Distributor:http://www.suvsystem.com/l/IC(Integrated-Circuits)-1.html

LED Distributor:http://www.suvsystem.com/l/LED-1.html

Capacitor Distributor:http://www.suvsystem.com/l/Capacitor-1.html

Transistor Distributor:http://www.suvsystem.com/l/Transistors-1.html

Resistor Distributor:http://www.suvsystem.com/l/Resistors-1.html

Diode Distributor:http://www.suvsystem.com/l/Diodes-1.html

SUV System Ltd insists on the managing faith ofsincereness,speciality,foresight, win-win,so we build up stable-relationship customers located all over the world, including the States, Europe, Argentina, UAE, Malaysia, Australia,and India etc

we are focus on the following fields,and hope we can help you.

INTERSIL IC Schottky Diodes High Precision Resistors ON Transistors Vishay resistors IR transistor Fast Recovery Diodes INFLNEON Diodes DIODES Transistors ALTERA IC MURATA IC IC(Integrated Circuits) MAXIM IC PANASONIC Low Ohmic Resistors LINEAR IC TDK IC VISHAY IC NXP Transistors HARRIS IC IR Diodes LED ROHM Resistors Capacitor Switching Diodes Current Sensors Resistors LITTELFUSE Diodes Thick Film Resistors TI IC LED part Switches Digital Transistors Industrial IC Renesas parts IC Texas Instruments(TI) IC Diodes Inc Voltage Regulators Transistors FAIRCHILD diodes Infineon Technologies Transistors Transistors Freescale
http://www.suvsystem.com/a/4008.aspx