Science Current Events | Science News | Brightsurf.com
 
Email a Friend Send to a friend
Printer Friendly Print Emory Researcher Finds Crayfish Fossils Provide Missing Evolutionary Link

Emory Researcher Finds Crayfish Fossils Provide Missing Evolutionary Link

February 07, 2008

Crayfish body fossils and burrows discovered in Victoria, Australia, have provided the first physical evidence that crayfish existed on the continent as far back as the Mesozoic Era, says Emory University paleontologist Anthony Martin, who headed up a study on the finds.

"Studying the fossil burrows gives us a glimpse into the ecology of southern Australia about 115 million years ago, when the continent was still attached to Antarctica," says Martin, a senior lecturer in environmental studies at Emory and an honorary research associate at Monash University in Melbourne. During that era, diverse plants grew in what is today Antarctica and dinosaurs roamed in prolonged polar darkness along southern Australia river plains. The period is of particular interest to scientists since it is believed to be the last time the Earth experienced pronounced global warming, with an average temperature of 68 degrees Fahrenheit - just 10 degrees warmer than today.




On Feb. 2, the earth science journal Gondwana Research published online the results of the crayfish study, which was conducted by Martin and a consortium of Australian scientists, including Thomas Rich and Gary Poore of the Museum of Victoria; Mark Schultz and Christopher Austin of Charles Darwin University; and Lesley Kool and Patricia Vickers-Rich of Monash.

The crayfish body fossils consist of an abdomen and two claws, and the fossil burrows are nearly identical to those made by modern crayfish in southeastern Australia. "Comparing these fossil burrows to those made by modern crayfish in Australia shows us that their behavior hasn't changed that much," says Martin, who specializes in trace fossils.

Biologists have long been fascinated by crayfish, due to their wide range - the freshwater decapods are found on almost every continent and have adapted to extremely diverse environments. Thomas Huxley, a colleague of Charles Darwin, was the first scientist to ponder how crayfish, which cannot survive in saltwater, could have spread to so many continents, according to Martin. Such studies helped lay the groundwork for plate tectonics, which revolutionized the earth sciences in the 1960s through the theory that the continents were once connected. More recently, molecular biologists have theorized that all Southern Hemisphere crayfish originated in southeastern Australia.

"The evolution of Southern Hemisphere crayfish has challenged researchers since the 1870s," Martin says. "Only now, 140 years later, are we starting to put together the physical evidence for this evolution through the discovery of fossils."

Emory University



Related Crayfish Current Events and Crayfish News Articles Crayfish Current Events and Crayfish News RSS Crayfish Current Events and Crayfish News RSS
Climate change triggered dwarfism in soil-dwelling creatures of the past
Ancient soil-inhabiting creatures decreased in body size by nearly half in response to a period of boosted carbon dioxide levels and higher temperatures, scientists have discovered.

Biologists discover 'death stench' is a universal ancient warning signal
The smell of recent death or injury that repels living relatives of insects has been identified as a truly ancient signal that functions to avoid disease or predators, biologists have discovered.

Dinosaur Burrow Find Gives Climate Change Clues
On the heels of his discovery in Montana of the first trace fossil of a dinosaur burrow, Emory University paleontologist Anthony Martin has found evidence of more dinosaur burrows - this time on the other side of the world, in Victoria, Australia.

Resilin springs simplify the control of crustacean limb movements
Animals can simplify the brain control of their limb movements by moving a joint with just one muscle that operates against a spring made of the almost perfect elastic substance called resilin.

Biological invasions increasing due to freshwater impoundments, says CU-Boulder study
The growing number of dams and other impoundments is increasing the number of invasive species and the speed at which they spread, putting natural lakes at risk, says a study led by the University of Colorado at Boulder.

Study: DNA barcoding in danger of 'ringing up' wrong species
DNA barcoding is a movement to catalog all life on earth by a simple standardized genetic tag, similar to stores labeling products with unique barcodes. The effort promises foolproof food inspection, improved border security, and better defenses against disease-causing insects, among many other applications.

480-million-year-old fossil sheds light on 150-year-old paleontological mystery
Discovery of an exceptional fossil specimen in southeastern Morocco that preserves evidence of the animal's soft tissues has solved a paleontological puzzle about the origins of an extinct group of bizarre slug-like animals with rows of mineralized armor plates on their backs, according to a paper in Nature.

New map outlines risk of zebra mussel invasion
The spread of two invasive alien freshwater mussel species - the zebra mussel and the quagga mussel - appears to be controlled in part by calcium levels in streams and lakes and a new risk assessment based on water chemistry suggests the Great Plains and American Southwest could be next in line for invasion.

What gives us sunburn protects crayfish against bacteria
The production of melanin gives us sunburns, but it also helps invertebrate animals to encapsulate attacking fungi and parasites.

Ritualized submission and pseudo-copulation reduce aggression among male crayfish
Pseudo-copulation-an interaction that mimics sexual copulation-is a behavior known in mammalian communities that reduces aggression and signifies social dominance, particularly among males.
More Crayfish Current Events and Crayfish News Articles
The Life Cycle of a Crayfish

The Life Cycle of a Crayfish
by Bobbie Kalman (Author), Rebecca Sjonger (Author)

Ages 6 to 12 years. The Life Cycle of a Crayfish provides children with a wealth of information about this interesting animal, such as where it lives and how it reproduces. Topics include different species, stages of their lives, how mothers care for their young, and how crayfish find food.

Small Scale Crayfish Farming

Small Scale Crayfish Farming
by Don Wilson (Author)



Pinching Crayfish (Pull Ahead Books)

Pinching Crayfish (Pull Ahead Books)
by Janet Piehl (Author)



RED CLAW! Raising the Giant Australian Freshwater Crayfish

RED CLAW! Raising the Giant Australian Freshwater Crayfish
by Don R. Wilson (Author)

The Red Claw crayfish is a new and very promising aquaculture species. The Red Claw is very similar to the native American species, except that it grows to a HUGE size--almost to that of a lobster! There are several other notable differences, such as year-round breeding, awesome fecundity... often over 700 eggs per breeder! They also have a non-aggressive nature, which allows many more Red Claw crayfish to live happily in a given space than would the native American crayfish.

This book is one of the few sources for complete information on all aspects of the culture of this lobster sized freshwater crayfish. Compiled from leading edge research direct from Australia as well as individual and University findings from all over the U.S.,this book dispels the hype and furnishes the facts...

3 lbs. Crawfish

3 lbs. Crawfish
by Charleston Seafood



Crayfish (Early Bird Nature Books)

Crayfish (Early Bird Nature Books)
by Phyllis W. Grimm (Author), Jerry Boucher (Author), Jerry Boucher (Photographer)



Storm Original Wiggle Wart 05 Fishing Lures (Naturistic Brown Crayfish, Size- 2)

Storm Original Wiggle Wart 05 Fishing Lures (Naturistic Brown Crayfish, Size- 2)
by Storm

Storm's Original Wiggle Wart is a strike-triggering crankbait that works when nothing else will! The Wiggle Wart's tough molded body and irresistible wide, side-to-side searching action has made the Original Wiggle Wart a mainstay in many top pro anglers' tackle box. Outfitted with all the original components, a cadence-style rattle, integrated lip design and super strong hooks. Body length: 2''.

Freshwater Crayfish Aquaculture in North America, Europe, and Australia: Families Astacidae, Cambaridae, and Parastacidae

Freshwater Crayfish Aquaculture in North America, Europe, and Australia: Families Astacidae, Cambaridae, and Parastacidae
by Jay Huner (Author)

Freshwater Crayfish Aquaculture in North America, Europe, and Australia is the first text to summarize the methods of culture for the eight most important crayfish species in the world. Methods developed to culture crayfishes around the world differ significantly, and this book enables readers to develop workable strategies for cultivating different crayfish species in specific environments.

Huner and associate authors cover the following topics in detail: methods of crayfish culture crayfish diseases crayfish processing economics of crayfish culture

Each of the the three major crayfish industries are well-represented in this new book and special attention is given to the specific needs and accomplishments of each area, which is beneficial to producers in other...

Crayfish Fishing Sea Fisherman French Print 1865

Crayfish Fishing Sea Fisherman French Print 1865
by old-print

Old Antique Historical Victorian Prints Maps and Historic Fine Art----------. Crayfish Fishing Sea Fisherman French Print 1865 Part Page From An Issue 1859 L'Univers Illustre Published In France Prorata Of Full Page Size 15 X 11

Crayfish Model Activity Set; Keyed Model (18.4 x 24.4 in.); Transparencies

Crayfish Model Activity Set; Keyed Model (18.4 x 24.4 in.); Transparencies
by American Educational Products

Models, anatomical and cellular; Crayfish; Activity set; 18.4 x 24.4 in. (46 x 61cm) keyed model of crayfish; With inset diagram detailing gill structure; Includes instructional materials, full-color overhead transparency; blackline master

© 2009 BrightSurf.com