(Press-News.org) VIDEO:
This is the CT image of the skull of the holotype of Eodelphis kabatensis.
Click here for more information.
Dolphins are the most diverse family of living marine mammals and include species such as the bottlenose dolphin and the killer whale. However, their early evolution and fossil record has been steeped in mystery due to lack of good specimens. A new paper published in latest issue of the Journal of Vertebrate Paleontology re-describes the oldest species of dolphin with a new name: Eodelphis kabatensis. Although the partial skull was previously described in the 1970s the scientific community largely overlooked it. The new re-description has important implications for the evolutionary history of dolphins.
The skull of Eodelphis kabatensis was originally collected from a small tributary of the Oshirarika River in Hakkaido, Japan from an outcrop of the Mashike Formation. Researchers working on the specimen have narrowed its age to the late Miocene (13.0-8.5 million years ago), making it the earliest true dolphin species described. "The early evolution of true dolphins is still covered in mystery. Eodelphis kabatensis informs us about the morphology of early dolphins", said lead author Mizuki Murakami.
Eodelphis is an important link in the evolutionary history of dolphins. Prior to this study, there was inconsistency between the fossil record of the dolphins and molecular-based studies. The oldest true dolphin fossils found were less than 6 million years old, while molecular studies suggested they originated and started to diversity between 9-12 million years ago. "Eodelphis kabatensis, being discovered from sediments that were deposited 8-13 million years ago, has largely resolved this discrepancy and provides the best glimpse yet of what the skull of the first dolphins may have looked like", said Jonathan Geisler, a marine mammal paleontologist at the New York Institute of Technology College of Osteopathic Medicine.
In addition to its importance as the earliest true dolphin, this new study also incorporates the most comprehensive analysis of the relationships within the Delphinoidea, the group that encompasses toothed whales. By including Eodelphis in the analysis, the authors were able to get a much clearer picture of the evolution of the toothed whales. Furthermore, the presence of Eodelphis in the Pacific Ocean during the late Miocene has implications for the geographic history of dolphins. While more specimens need to be discovered, this study suggests that dolphins might have had their origins in the Pacific.
INFORMATION:
About the Society of Vertebrate Paleontology
Founded in 1940 by thirty-four paleontologists, the Society now has more than 2,300 members representing professionals, students, artists, preparators, and others interested in VP. It is organized exclusively for educational and scientific purposes, with the object of advancing the science of vertebrate paleontology.
Journal of Vertebrate Paleontology
The Journal of Vertebrate Paleontology (JVP) is the leading journal of professional vertebrate paleontology and the flagship publication of the Society. It was founded in 1980 by Dr. Jiri Zidek and publishes contributions on all aspects of vertebrate paleontology.
For complimentary access to the full article, visit: http://www.tandfonline.com/toc/ujvp20/current
The article appears in the Journal of Vertebrate Paleontology 34(3), published by Taylor and Francis
Citation: Murakami, M., C. Shimada, Y. Hikida, Y. Soeda, and H. Hirano. 2014. Eodelphis kabatensis, A New Name for the Oldest True Dolphin Stenella kabatensis Horikawa, 1977 (Cetacea, Odontoceti, Delphinidae), from the Upper Miocene of Japan, and the Phylogeny and Paleobiogeography of Delphinoidea. Journal of Vertebrate Paleontology 34(3):1-21.
Journal Web site: http://www.tandfonline.com/toc/ujvp20/current
Society of Vertebrate Paleontology: http://www.vertpaleo.org
AUTHOR CONTACT INFORMATION
Lead author:
Mizuki Murakami
Waseda University
Nishiwaseda 1-6-1
Shinjuku, Tokyo, Japan 169-8050
mizuki-m@aoni.waseda.jp
Other authors:
Chieko Shimada
c-shimada@aist.go.jp
Yoshinori Hikida
nmhikida@coral.ocn.ne.jp
Yuhji Soeda
Soeda.yuuji@pref.hokkaido.lg.jp
Hiromichi Hirano
hhirano@waseda.jp
OTHER EXPERTS NOT DIRECTLY INVOLVED WITH THE STUDY
Jonathan Geisler
Associate Professor of Anatomy
Department of Anatomy
New York Institute of Technology
College of Osteopathic Medicine
Phone: (516) 686-7552
Email: jgeisler@nyit.edu
Anthony Friscia
Department of Integrative Biology and Physiology
University of California – Los Angeles
Phone: (310) 206-6011
Email: tonyf@ucla.edu
Redescription of the oldest-known dolphin skull sheds light on their origins and evolution
2014-05-06
[Attachments] See images for this press release:
ELSE PRESS RELEASES FROM THIS DATE:
One step closer to cell reprogramming
2014-05-06
In 2012, John B. Gurdon and Shinya Yamakana were awarded the Nobel Prize in medicine for discovering that adult cells can be reprogrammed into pluripotent ones (iPS); the cells obtained are capable of behaving in a similar way to embryonic stem cells, and hence have enormous potential for regenerative medicine.
However, although there are many research groups around the world studying this process, it is still not completely understood, it is not totally efficient, and it is not safe enough to be used as the basis for a new cell therapy.
Now, researchers at the Centre ...
Can you tell a person's gender by their video game avatar?
2014-05-06
This news release is available in French.
Montreal, May 6, 2014 — A sexy wood elf with pointy ears. A hulking ogre with blue skin. An intimidating heroine with a buxom breastplate. When it comes to computer games, players can choose to be anyone or anything. But gamers don't always mask their true identities with online avatars.
According to a new study by researchers at Concordia University, Colorado State University, Syracuse University, Hofstra University and the University of Toronto, a male gamer who chooses to play as a female character will still display ...
The Red Sea -- an ocean like all others, after all
2014-05-06
Pacific, Atlantic and Indian Ocean, with the land masses of the Americas, Europe, Asia, Africa and Australia in between – that's how we know our earth. From a geologist's point of view, however, this is only a snapshot. Over the course of the earth's history, many different continents have formed and split again. In between oceans were created, new seafloor was formed and disappeared again: Plate tectonics is the generic term for these processes.
The Red Sea, where currently the Arabian Peninsula separates from Africa, is one of the few places on earth where the splitting ...
Protein molecule may improve survival in deadly lung disease
2014-05-06
Researchers at the University of Illinois at Chicago College of Medicine have discovered a protein molecule that seems to slow the progression of pulmonary fibrosis, a progressive lung disease that is often fatal three to five years after diagnosis.
The finding is reported in the American Journal of Respiratory and Critical Care Medicine.
Nearly five million people worldwide are affected by pulmonary fibrosis, which causes the lungs to become covered in fibrous scar tissue and leads to shortness of breath that gets more severe as the disease progresses.
Chronic inflammatory ...
Two-lock box delivers cancer therapy
2014-05-06
Rice University scientists have designed a tunable virus that works like a safe deposit box. It takes two keys to open it and release its therapeutic cargo.
The Rice lab of bioengineer Junghae Suh has developed an adeno-associated virus (AAV) that unlocks only in the presence of two selected proteases, enzymes that cut up other proteins for disposal. Because certain proteases are elevated at tumor sites, the viruses can be designed to target and destroy the cancer cells.
The work appears online this week in the American Chemical Society journal ACS Nano.
AAVs are ...
Donor livers preserved and improved with room-temperature perfusion system
2014-05-06
A system developed by investigators at the Massachusetts General Hospital (MGH) Center for Engineering in Medicine (CEM) and the MGH Transplant Center has the potential to increase both the supply and the quality of donor organs for liver transplantation. In their report, which has been published online in the American Journal of Transplantation, the research team describes how use of a machine perfusion system delivering a supply of nutrients and oxygen though an organ's circulation at room temperature preserved and improved the metabolic function of donor livers in a ...
Study: Concussion rate in high-school athletes more than doubled in 7-year period
2014-05-06
COLUMBUS, Ohio – Concussion rates in U.S. high-school athletes more than doubled between 2005 and 2012, according to a new national study using data on nine team sports.
Overall, the rate increased from .23 to .51 concussions per 1,000 athlete exposures. An athlete exposure is defined as one athlete participating in one competition or practice.
The increase might appear to sound an alarm about sports safety, but the researchers suspect the upward trend in reported concussions reflects increased awareness – especially because the rates went up the most after the 2008-09 ...
Childhood obesity trends -- not time to celebrate, yet
2014-05-06
New Rochelle, NY, May 6, 2014—Despite reports in the media that the obesity rate among young children has declined dramatically during the past 10 years, that is not the conclusion reached by recent studies published in the medical literature. Those studies did, however, reveal some potentially encouraging findings, which are detailed in the Editorial "Childhood Obesity Trends: Time for Champagne?" published in Childhood Obesity, a peer-reviewed journal from Mary Ann Liebert, Inc., publishers. The article is available free on the Childhood Obesity website at http://www.liebertpub.com/chi.
"The ...
Ban cigarette filters to save the environment, suggest researchers
2014-05-06
Ban cigarette filters. Start a deposit-return scheme for used butts. Hold manufacturers responsible for clean-ups. Place warnings on packets about the impact of simply flicking one's used cigarettes away. These are among the policy measures that Thomas Novotny of the San Diego State University in the US and Elli Slaughter advocate to curb the environmental harm done through the large-scale littering of cigarette butts, packaging and matches. The suggestions are part of a review article in Springer's journal Current Environmental Health Reports.
Cigarette butts and other ...
Neutron star magnetic fields: Not so turbulent, after all?
2014-05-06
Neutron stars, the extraordinarily dense stellar bodies created when massive stars collapse, are known to host the strongest magnetic fields in the universe -- as much as a billion times more powerful than any man-made electromagnet. But some neutron stars are much more strongly magnetized than others, and this disparity has long puzzled astrophysicists.
Now, a study by McGill University physicists Konstantinos Gourgouliatos and Andrew Cumming sheds new light on the expected geometry of the magnetic field in neutron stars. The findings, published online April 29 in Physical ...