A team of researchers from the University of Bristol studying the "living fossil" tuatara or Sphenodon, has found a new way to measure the evolutionary rate of these enigmatic creatures giving credence to Darwin's theory of living fossils. The discovery is a very important phase for the theory.
According to Science Daily, tuatara is a large lizard-like animal that once lived in the mainland's of New Zealand but has been pushed to smaller offshore islands by human activities. Tuataras are not actually lizards but they share a common ancestor from about 240 million years ago and have survived as an independent evolutionary line for all that time.
Charles Darwin invented the term "Living fossil" in the year 1859. At that time of deriving the theory, the reference was made to the living species that look just similar to their ancestors million years ago. In a study, researchers measured jaw bones of all the fossil relatives of the living tuatara and compared the evidence of dietary adaptation.
According to Long Room, the study of evolution confirms that tuatara has shown a very slow evolution as expected and most importantly its anatomy is very conservative. "The relative fossil of tuatara included aquatic forms and plant eaters which were very much diverse than today. It was also found that living tuatara shares in common with its oldest relatives from Triassic," as per a lead author, PhD student, Jorge Herrera Flores.
The term living "living fossil" seems amorphous according to many biologists. However, a clear computational way has been found to measure the evolutionary rate. The most important discovery about living tuatara is that its adaptation is central among all its fossils relatives.
Thus one can say that tuatara is conservative just like its relatives from 200 million years ago. With the theory of Darwin, one can numerically test what is and what not is a living fossil. And most importantly these tests can be done on other classic species also.
