* Astronomy

Members Login
Post Info TOPIC: Shark


L

Posts: 130085
Date:
Pucapampella Shark
Permalink  
 


Remains of prehistoric shark found near Peru's Lake Titicaca

Students from the State University of Puno, in southern Peru, have discovered the remains of a prehistoric shark near Lake Titicaca, said the Ministry of Culture on Friday.
Called "Pucapampella Shark," it is believed to be the 400- million-year-old precursor to today's vertebrae.
The fossil was unearthed at the paleontological site of Imarrucos, northwest of Titicaca, the world's highest navigable lake, said the ministry.

Read more



__________________


L

Posts: 130085
Date:
Chimaeroids
Permalink  
 


280 million-year-old fossil reveals evolutionary origins of shark-like fishes

High-definition CT scans of the fossilized skull of a 280 million-year-old fish reveal the origin of chimaeras, a group of cartilaginous fish related to sharks. Analysis of the brain case of Dwykaselachus oosthuizeni, a shark-like fossil from South Africa, shows telltale structures of the brain, major cranial nerves, nostrils and inner ear belonging to modern-day chimaeras.
This discovery, published early online in Nature on Jan. 4, allows scientists to firmly anchor chimaeroids - the last major surviving vertebrate group to be properly situated on the tree of life - in evolutionary history, and sheds light on the early development of these fish as they diverged from their deep, shared ancestry with sharks.

Read more



__________________


L

Posts: 130085
Date:
RE: Shark
Permalink  
 


Last Ice Age has shaped sharks across Europe

Shark populations in the Mediterranean are highly divided, an international team of scientists, led by Dr Andrew Griffiths of the University of Bristol, has shown.
Many previous studies on sharks suggest they move over large distances. But catsharks in the Mediterranean Sea appear to move and migrate much less, as revealed by this study. This could have important implications for conserving and managing sharks more widely, suggesting they may be more vulnerable to over-fishing than previously thought.

Read more



__________________


L

Posts: 130085
Date:
Permalink  
 

First ban on shark and manta ray trade comes into force

Read more



__________________


L

Posts: 130085
Date:
Ancient sharks
Permalink  
 


Ancient shark teeth give clues to future of Arctic climate change

A new study of sharks that lived in warm Arctic waters millions of years ago suggests that some shark species could handle the falling Arctic salinity that may come with rising temperatures.
The Arctic today is best known for its tundra and polar bear population, but roughly 38 to 53 million years ago during the Eocene epoch, the Arctic was like a huge temperate forest with brackish water, home to a variety of animal life, including ancestors of tapirs, hippo-like creatures, crocodiles and giant tortoises. Much of what is known about the region during this period comes from well-documented terrestrial deposits. Marine records have been harder to come by.

Read more



__________________


L

Posts: 130085
Date:
RE: Shark
Permalink  
 


Artefacts offer Pacific shark species absence clues

Nineteenth Century tools made from sharks' teeth suggest that two species of shark used to populate the Central Pacific but are no longer present.
Using artefacts from museums, a team of US researchers found that spot-tail and dusky sharks used to inhabit the reefs surrounding the Gilbert Islands.

Read more



__________________


L

Posts: 130085
Date:
Permalink  
 

Shark-tooth weapons reveal lost biodiversity

For centuries, the people of the Gilbert Islands in the central Pacific Ocean have crafted weapons from shark teeth. Joshua Drew, a conservation biologist at Columbia University in New York, has used these teeth to show that the waters around the islands - part of the Republic of Kiribati -were once home to three species of shark that no longer live in the area.
Read more



__________________


L

Posts: 130085
Date:
Permalink  
 

Scientists have confirmed the second-ever case of a "virgin birth" in a shark, indicating once again that female sharks can reproduce without mating and raising the possibility that many female sharks have this incredible capacity. This compelling new study will be published today in the latest issue of the Journal of Fish Biology, a leading international journal.
Lead author Dr. Demian Chapman, shark scientist with the Institute for Ocean Conservation Science at Stony Brook University, Beth Firchau, Curator of Fishes for the Virginia Aquarium & Marine Science Center, and Dr. Mahmood Shivji, Director of the Guy Harvey Research Institute and Professor at Nova Southeastern University in Florida, have proven through DNA testing that the offspring of a female blacktip shark named Tidbit contained no genetic material from a father. Tidbit had lived at the Virginia Aquarium in the Norfolk Canyon Aquarium for eight years since shortly after her birth in the wild.

Stony Brook University

__________________
Page 1 of 1  sorted by
Quick Reply

Please log in to post quick replies.



Create your own FREE Forum
Report Abuse
Powered by ActiveBoard