• A fossilised skull of a small critter found in Utah underneath a dinosaur foot bone is providing insight into one of the most primitive mammalian groups and has scientists rethinking the timing of the break-up of Earth’s bygone supercontinent Pangaea.
  • Scientists described the cranium of a small primitive Cretaceous Period mammal called Cifelliodon wahkarmoosuch, about the size of a small hare, that lived 130 million years ago, boasting traits suggesting it possessed a keen sense of smell and may have been nocturnal.
  • The three-inch skull was well preserved and nearly complete, unlike the usual scrappy fossils of the group to which Cifelliodon belonged, called
  • The earliest primitive mammals evolved during the Triassic Period, when dinosaurs also first appeared, from creatures that combined reptilian and mammalian characteristics.

What about the Haramiyidans?

  • Haramiyidans appeared close to the dawn of the mammalian lineage, with the earliest-known representative living about 208 million years ago and the last-known member perhaps about 70 million years ago.
  • The skull was unwittingly excavated at a site north of Arches National Park in eastern Utah.
  • It may be the best-preserved skull of any haramiyidan, offering a new understanding of the group.
  • Before a geological process called plate tectonics rendered them separate land masses, the Americas, Eurasia, Africa, Antarctica, Australia and India all were part of a huge, single continent called Pangaea.
  • The timing for Pangaea’s breakup, initially into two major land masses, has been a matter of scientific debate.
  • The researchers said the discovery of Cifelliodon, which had a close contemporaneous relative in Africa, suggests there were still connections between the northern hemisphere continents and those in the southern hemisphere 15 million years later than previously believed.