Navigation Links
Family tree of fish yields surprises

The mighty tuna is more closely related to the delicate 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. 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.


Contact: Andy Fell
University of California - Davis

Related biology news :

1. Merkin Family Foundation to fund next generation of Broad Institute scientists
2. Family history of liver cancer increases risk of developing the disease
3. Starting a family does not encourage parents to eat healthier
4. Discovery of a new family of key mitochondrial proteins for the function and viability of the brain
5. Family values
6. FirstMark Exhibiting and Presenting at the San Diego Academy of Family Physicians 55th Annual Postgraduate Symposium
7. Parkinsons disease gene identified with help of Mennonite family: UBC-VCH research
8. Helping family is key for social birds
9. Millipede family added to Australian fauna
10. CEVA, Rubidium Partner to Deliver Speech Processing Solutions based on the CEVA-TeakLite Family of DSPs
11. Bloomberg School receives $28 million for family planning advocacy
Post Your Comments:
(Date:11/4/2015)... --> --> ... Transparency Market Research "Home Security Solutions Market - Global Industry ... 2022", the global home security solutions market is expected to reach ... market is estimated to expand at a CAGR of ... Rising security needs among customers at homes, the emergence ...
(Date:10/29/2015)...  The J. Craig Venter Institute (JCVI) policy group ... Biosecurity: Lessons Learned and Options for the Future," which ... Services guidance for synthetic biology providers has worked since ... --> --> Synthetic biology promises great ... pose unique biosecurity threats. It now is easier than ...
(Date:10/29/2015)... health pioneer, Joseph C. Kvedar , MD, describes ... wellness, and the business opportunities that arise from it ... Healthy Things . Long before health and wellness ... vice president, Connected Health, Partners HealthCare, was creating a ... the hospital or doctor,s office into the day-to-day lives ...
Breaking Biology News(10 mins):
(Date:11/25/2015)... Md. , Nov. 25, 2015  PharmAthene, Inc. ... Directors has adopted a stockholder rights plan (Rights Plan) ... net operating loss carryforwards (NOLs) under Section 382 of ... --> PharmAthene,s use of its NOLs ... "ownership change" as defined in Section 382 of the ...
(Date:11/25/2015)... Nov. 25, 2015  Neurocrine Biosciences, Inc. (Nasdaq: ... President and CEO of Neurocrine Biosciences, will be presenting ... New York . ... website approximately 5 minutes prior to the presentation to ... the presentation will be available on the website approximately ...
(Date:11/25/2015)... , November 25, 2015 ... Research Report is a professional and in-depth study ...      (Logo: ) , ... of the industry including definitions, classifications, applications and ... provided for the international markets including development trends, ...
(Date:11/24/2015)... Cepheid (NASDAQ: CPHD ) today announced ... conference, and invited investors to participate via webcast. ... December 1, 2015 at 11.00 a.m. Eastern Time ... December 1, 2015 at 11.00 a.m. Eastern Time ... York, NY      Tuesday, December 1, 2015 at ...
Breaking Biology Technology: