Date:11/19/2012

entina. Wible is known for his work on the origins and evolutionary relationships among the three modern mammal groups: placentals (live-bearing mammals such as humans), marsupials (pouched mammals such as opossums), and egg-laying mammals (such as platypuses). Despite being excellently preserved, the mysterious fossils moved from institution to institution and researcher to researcher, the classification of Necrolestes changing with each new move. As recently as a few years ago, Necrolestes still could not be definitively classified in a mammal group. A CAT scan of the ear region in 2008 led to another research teams hypothesis that Necrolestes was a marsupial. This classification intrigued Wibles co-author on the paper, Guillermo Rougier from the University of Louisville, Kentucky. As a specialist in South American mammals, Rougier was not convinced that the marsupial identification was accurate, and he embarked on his own attempt to make a classification. This project was a little daunting, because we had to contradict 100 years of interpretation, admits Rougier. During the process of preparing the fossil for further study, Rougier uncovered characteristics of the skull anatomy that had previously gone unnoted. Based on these newly revealed features, the research team came to the groundbreaking realization that Necrolestes belonged to neither the marsupial nor placental lineages to which it had historically been linked. Rather, Necrolestes actually belonged in a completely unexpected branch of the evolutionary tree which was thought to have died out 45 million years earlier than the time of Necrolestes.

Confusing anatomy

Part of the riddle of Necrolestes has always been its seemingly mismatched anatomical features, which never seemed to fit any single classification. Based on its decidedly upturned snout, sturdy body structure, and short, wide leg bones, researchers had always agreed that
'/>"/>

Contact: Leigh Kish KishL@carnegiemnh.org 412-622-3361 Carnegie Museum of Natural History Source:Eurekalert

0 GOOD

Page: 1 2 3 4 5
Related biology news :

1. 1 year after Fukushima
2. AGU: Venice hasnt stopped sinking after all
3. Black flies may have a purpose after all
4. Estrogen hormone reveals protective ability after traumatic brain injury
5. Obstructive sleep apneas damage evident after 1 month
6. Scientists read the ash from the Icelandic volcano 2 years after its eruption
7. Microbial communities shifted dramatically after Deepwater Horizon spill
8. Regenerated cells may restore vision after corneal dysfunction
9. Cinega de Santa Clara unchanged after pilot run of Yuma Desalting Plant
10. Promiscuous squid fatigued after mating
11. Ethylene of no effect - why peppers do not mature after picking