Free Newsletters - Space - Defense - Environment - Energy - Solar - Nuclear
..
. 24/7 Space News .




EARLY EARTH
100 million-year-old coelacanth discovered in Texas is new fish species from Cretaceous
by Margaret Allen
Dallas TX (SPX) Oct 26, 2012


The SMU specimen demonstrates there was greater diversity among coelacanths during the Cretaceous than previously known.

A new species of coelacanth fish has been discovered in Texas. Pieces of tiny fossil skull found in Fort Worth have been identified as 100 million-year-old coelacanth bones, according to paleontologist John F. Graf, Southern Methodist University, Dallas. The coelacanth has one of the longest lineages - 400 million years - of any animal. It is the fish most closely related to vertebrates, including humans.

The SMU specimen is the first coelacanth in Texas from the Cretaceous, said Graf, who identified the fossil. The Cretaceous geologic period extended from 146 million years ago to 66 million years ago.

Graf named the new coelacanth species Reidus hilli.

Coelacanths have been found on nearly every continent
Reidus hilli is now the youngest coelacanth identified in the Lone Star State.

Previously the youngest was a 200 million-year-old coelacanth from the Triassic. Reidus hilli is the first coelacanth ever identified from the Dallas-Fort Worth area.

Coelacanth fossils have been found on every continent except Antarctica. Few have been found in Texas, Graf said.

The coelacanth fish has eluded extinction for 400 million years. Scientists estimate the coelacanth reached its maximum diversity during the Triassic.

The coelacanth was thought to have gone extinct about 70 million years ago. That changed, however, when the fish rose to fame in 1938 after live specimens were caught off the coast of Africa. Today coelacanths can be found swimming in the depths of the Indian Ocean.

"These animals have one of the longest lineages of any vertebrates that we know," Graf said.

The SMU specimen demonstrates there was greater diversity among coelacanths during the Cretaceous than previously known.

"What makes the coelacanth interesting is that they are literally the closest living fish to all the vertebrates that are living on land," he said. "They share the most recent common ancestor with all of terrestrial vertebrates."

Coelacanths have boney support in their fins, which is the predecessor to true limbs.

"Boney support in the fins allows a marine vertebrate to lift itself upright off the sea floor," Graf said, "which would eventually lead to animals being able to come up on land."

Texas coelacanth, Reidus hilli, represents a new species and a new family
Graf identified Reidus hilli from a partial skull, including gular plates, which are bones that line the underside of the jaw.

"Coelacanths are not the only fish that have gular plates, but they are one of the few that do," Graf said. "In fact, the lenticular shape of these gular plates is unique to coelacanths. That was the first indicator that we had a fossil coelacanth."

Reidus hilli was an adult fish of average size for the time in which it lived, said Graf. While modern coelacanths can grow as large as 3 meters, Reidus hilli was probably no longer than 40 centimeters. Its tiny skull is 45 millimeters long by 26 millimeters wide, or about 1.75 inches long by 1 inch wide.

Reidus hilli's total body size is typical of the new family of coelacanths, Dipluridae, which Graf describes and names. He chose the name for the least primitive coelacanth in the family, Diplurus, which lived during the Triassic.

"Reidus hilli helped me tie a group of coelacanths together into what I identify as a new family of coelacanths," he said. "This family represents a transition between the two large groups of youngest living coelacanths from the fossil record, Mawsoniidae and Latimeriidae."

Diplurid coelacanths are typically smaller than the two families with which they are most closely associated, Mawsoniidae and Latimeriidae. Mawsoniidae and Latimeriidae both have late Cretaceous members reaching large body sizes, ranging from 1 meter to 3 meters in total body length, Graf said.

Reidus hilli provides clues to missing coelacanth history
Reidus hilli is named, in part, for the amateur collector who discovered the fish, Robert R. Reid.

A Fort Worth resident, Reid has collected fossils for decades. He found the fossil specimen while walking some land that had been prepared for construction of new homes. Reid noticed the fossil lying loose on the ground in a washed out gully created by run-off.

Following Graf's analysis, Reid was surprised to learn he'd collected a coelacanth - and a new species.

"When I found it, I could tell it was a bone but I didn't think it was anything special," said Reid, recalling the discovery. "I certainly didn't think it was a coelacanth."

At the time, SMU paleontologist Louis L. Jacobs recommended to Reid that he donate the fossil and have it scientifically identified. Reid gave the fossil to SMU's Shuler Museum of Paleontology in the Roy M. Huffington Department of Earth Sciences.

"It is astounding what can be learned from the discoveries that people like Rob Reid make in their own backyards," said Jacobs, an SMU professor of earth sciences and president of SMU's Institute for the Study of Earth and Man.

"The discovery of living coelacanths in the Indian Ocean after being presumed extinct for 70 million years highlights one of the great mysteries of ocean life. Where were they all that time? The new fossil from Texas is a step toward understanding this fascinating history."

Reidus hilli is the latest of many fossils Reid has discovered. Others also have been named for him.

Reidus hilli discovered in Duck Creek Formation of North Texas
Reidus hilli came from the fossil-rich Duck Creek Formation, which is a layer-cake band of limestone and shale about 40 feet thick.

The fossil was found in marine sediments, Graf said. It is one of many marine fossils found in the North Texas area, which 100 million years ago was covered by the Western Interior Seaway that divided North America from the Gulf of Mexico to the Arctic Ocean.

"That is unique to younger coelacanths," Graf said. "The oldest coelacanths were usually found in freshwater deposits and it wasn't until the Cretaceous that we start seeing this transition into a more marine environment."

Fossil also named for Robert T. Hill, "Father of Texas Geology" Graf also named the fossil for Robert T. Hill, a geologist with the U.S. Geological Survey who led surveys of Texas during the 1800s. Hill described much of the geology of Texas, including the Duck Creek Formation. Hill is acclaimed as the "Father of Texas Geology."

Identification of Reidus hilli brings the number of coelacanth species worldwide to 81, including two that are alive today. Sources report that 229 living coelacanths have been caught since 1938.

Graf reported his findings in "A new Early Cretaceous coelacanth from Texas," published in Historical Biology: An International Journal of Paleobiology. Graf is a paleontology graduate student in SMU's Huffington Department of Earth Sciences.

.


Related Links
Southern Methodist University
Explore The Early Earth at TerraDaily.com






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





EARLY EARTH
Study: Heat prolonged ancient extinctions
Leeds, England (UPI) Oct 19, 2012
European scientists say they've discovered why a "dead zone" following the worst extinction of all time lasted so long - it was simply too hot to survive. Researchers have studied what happened after a mass extinction around 250 million years ago in the pre-dinosaur era wiped out nearly all the world's species. Such mass extinctions are usually followed by a "dead zone" - durin ... read more


EARLY EARTH
NASA's LADEE Spacecraft Gets Final Science Instrument Installed

Astrium presents results of its study into automatic landing near the Moon's south pole

European mission to search for moon water

Model reconciles Lunar Earth composition with giant impact theory

EARLY EARTH
Opportunity Undertakes Survey Drives Of Local Area

Assessing Drop-Off to Mars Rover's Observation Tray

Valles Marineris - the largest canyon in the Solar System

Curiosity Rover Collects Fourth Scoop of Martian Soil

EARLY EARTH
Space daredevil Baumgartner is 'officially retired'

NASA must reinvest in nanotechnology research, according to new Rice University paper

Austrian space diver no stranger to danger

Baumgartner feat boosts hopes for imperilled astronauts

EARLY EARTH
China to launch 11 meteorological satellites by 2020

China makes progress in spaceflight research

Patience for Tiangong

China launches civilian technology satellites

EARLY EARTH
New crew docks with ISS: Russia

ISS Crew Gets Ready for New Expedition 33 Trio

New ISS Crew Confirmed

Russia launches three astronauts to ISS

EARLY EARTH
Pleiades 1B joins its launcher at the Spaceport for Arianespace's Soyuz mission in November

S. Korea readies third bid to join global space club

Brazil eyes closer space cooperation with Ukraine

S. Korea plans third rocket launch bid Friday

EARLY EARTH
New Study Brings a Doubted Exoplanet 'Back from the Dead'

New small satellite will study super-Earths for ESA

Most Planetary Systems are 'Flatter than Pancakes'

Glitch could end NASA planet search

EARLY EARTH
A new take on the Midas touch - changing the colour of gold

Northrop Grumman Matures Laser Threat Terminator Technology to Address Emerging Threats

US DoE's Ames Laboratory improving process to recycle rare-earth materials

Droplet response to electric voltage in solids exposed




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement