Two sets of fossils discovered more than 40 years apart suggest that small mammals that lived during the Middle Jurassic period had longer “childhood” periods and longer life spans than their modern-day counterparts, according to a new study published Wednesday in the journal Nature. Nature Examine the fossilized remains Cruxatodon kiltlingtonensisIt was a mouse-like creature that lived on the Isle of Skye in Scotland about 166 million years ago and became extinct long ago. The New York Times The prehistoric animal was described as “resembling a small possum and weighing less than a hockey puck.”
What makes the fossils particularly interesting is that one set of remains unearthed in the 1970s was of an adult animal, while a second set discovered in 2016 was of a juvenile. “That meant we could ask questions that we never dreamed of with just one specimen,” says paleontologist Elsa Panciroli, a co-author of the study. New ScientistUsing X-ray imaging to examine the specimen’s teeth, the researchers found that the adult animal was about seven years old at the time of its death, “which is old compared to modern mammals of its size,” they said. TimesThe juveniles, on the other hand, were between 7 months and 2 years old – a surprise since the specimens had baby teeth, which led the researchers to believe they were younger.
“We expect teething to occur within the next few weeks to months,” Panciroli said. New Scientist“So we quickly realized that it must have grown very differently. [than modern species]The researchers: K. Quiltrington Dr. Panchroli and his team are not sure what caused this evolutionary change, but they speculate that it may have something to do with environmental or metabolic changes. (Read more) discovery story.
